1
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Söll A, Lopriore E, Ottesen A, Luxa J, Pasquale G, Sturala J, Hájek F, Jarý V, Sedmidubský D, Mosina K, Sokolović I, Rasouli S, Grasser T, Diebold U, Kis A, Sofer Z. High-κ Wide-Gap Layered Dielectric for Two-Dimensional van der Waals Heterostructures. ACS Nano 2024; 18:10397-10406. [PMID: 38557003 PMCID: PMC11025129 DOI: 10.1021/acsnano.3c10411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/13/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
van der Waals heterostructures of two-dimensional materials have unveiled frontiers in condensed matter physics, unlocking unexplored possibilities in electronic and photonic device applications. However, the investigation of wide-gap, high-κ layered dielectrics for devices based on van der Waals structures has been relatively limited. In this work, we demonstrate an easily reproducible synthesis method for the rare-earth oxyhalide LaOBr, and we exfoliate it as a 2D layered material with a measured static dielectric constant of 9 and a wide bandgap of 5.3 eV. Furthermore, our research demonstrates that LaOBr can be used as a high-κ dielectric in van der Waals field-effect transistors with high performance and low interface defect concentrations. Additionally, it proves to be an attractive choice for electrical gating in excitonic devices based on 2D materials. Our work demonstrates the versatile realization and functionality of 2D systems with wide-gap and high-κ van der Waals dielectric environments.
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Affiliation(s)
- Aljoscha Söll
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
| | - Edoardo Lopriore
- Institute
of Electrical and Microengineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Asmund Ottesen
- Institute
of Electrical and Microengineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jan Luxa
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
| | - Gabriele Pasquale
- Institute
of Electrical and Microengineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jiri Sturala
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
| | - František Hájek
- Institute
of Physics of the Czech Academy of Sciences, v.v.i., Cukrovarnická 10, 162 00, Prague 6, Czech Republic
| | - Vítězslav Jarý
- Institute
of Physics of the Czech Academy of Sciences, v.v.i., Cukrovarnická 10, 162 00, Prague 6, Czech Republic
| | - David Sedmidubský
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
| | - Kseniia Mosina
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
| | - Igor Sokolović
- Institute
of Microelectronics, TU Wien, Gußhausstraße 27−29, 1040 Vienna, Austria
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8−10, 1040 Vienna, Austria
| | - Saeed Rasouli
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8−10, 1040 Vienna, Austria
| | - Tibor Grasser
- Institute
of Microelectronics, TU Wien, Gußhausstraße 27−29, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8−10, 1040 Vienna, Austria
| | - Andras Kis
- Institute
of Electrical and Microengineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Zdeněk Sofer
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technicka 5, 166 28, Prague 6, Czech Republic
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2
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Wang C, Sombut P, Puntscher L, Jakub Z, Meier M, Pavelec J, Bliem R, Schmid M, Diebold U, Franchini C, Parkinson GS. CO-Induced Dimer Decay Responsible for Gem-Dicarbonyl Formation on a Model Single-Atom Catalyst. Angew Chem Int Ed Engl 2024; 63:e202317347. [PMID: 38294119 DOI: 10.1002/anie.202317347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 02/01/2024]
Abstract
The ability to coordinate multiple reactants at the same active site is important for the wide-spread applicability of single-atom catalysis. Model catalysts are ideal to investigate the link between active site geometry and reactant binding, because the structure of single-crystal surfaces can be precisely determined, the adsorbates imaged by scanning tunneling microscopy (STM), and direct comparisons made to density functional theory. In this study, we follow the evolution of Rh1 adatoms and minority Rh2 dimers on Fe3O4(001) during exposure to CO using time-lapse STM at room temperature. CO adsorption at Rh1 sites results exclusively in stable Rh1CO monocarbonyls, because the Rh atom adapts its coordination to create a stable pseudo-square planar environment. Rh1(CO)2 gem-dicarbonyl species are also observed, but these form exclusively through the breakup of Rh2 dimers via an unstable Rh2(CO)3 intermediate. Overall, our results illustrate how minority species invisible to area-averaging spectra can play an important role in catalytic systems, and show that the decomposition of dimers or small clusters can be an avenue to produce reactive, metastable configurations in single-atom catalysis.
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Affiliation(s)
- Chunlei Wang
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Panukorn Sombut
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Lena Puntscher
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Zdenek Jakub
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
- Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, 612 00, Czechia
| | - Matthias Meier
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
- Faculty of Physics, Center for Computational Materials Science, University of Vienna, Vienna, 1090, Austria
| | - Jiri Pavelec
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Roland Bliem
- Advanced Research Center for Nanolithography, 1098XG, Amsterdam, Netherlands
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Vienna, 1040, Austria
| | - Cesare Franchini
- Faculty of Physics, Center for Computational Materials Science, University of Vienna, Vienna, 1090, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, 40127, Italy
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3
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Advincula XR, Backus EHG, Bonn M, Cox SJ, Diebold U, Fellows A, Finney AR, Goel G, Hedley J, Jiang Y, Jin D, Kapil V, Kavokine N, Klein J, Laage D, Mohandas N, Morgenstern K, Mukherjee T, Olvera de la Cruz M, Orlikowska-Rzeznik H, Perkin S, Piaggi PM, Rodellar CG, Ryan P, Sayer T, Seyffertitz M, Shepelenko M, Sosso GC, Thämer M, Vilangottunjalil A, Walker-Gibbons R, Wang Y, Willard AP, Zhang P. Electrified/charged aqueous interfaces: general discussion. Faraday Discuss 2024; 249:381-407. [PMID: 38170868 DOI: 10.1039/d3fd90065g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
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4
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Advincula XR, Blow KE, Bonn M, Bui AT, Cheng Y, Cox SJ, Della Pia F, Diebold U, Fumagalli L, Goel G, Hayton JA, Jiang Y, Kapil V, Kavokine N, Koga K, Laage D, Lahav M, Miao S, Michaelides A, Montero de Hijes P, Morgenstern K, Mukherjee T, O'Neill N, Pan D, Piaggi PM, Rempe SLB, Salvalaglio M, Salzmann CG, Sayer T, Shepelenko M, Sosso GC, Wang S, Webber B, Willard AP, Yao Y. Dynamics and nano-rheology of interfacial water: general discussion. Faraday Discuss 2024; 249:243-266. [PMID: 38174388 DOI: 10.1039/d3fd90064a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
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5
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Advincula XR, Backus EHG, Bartels-Rausch T, Benaglia S, Ben Ari G, Blow KE, Bonn M, Bui AT, Cox SJ, Della Pia F, Diebold U, Finney AR, Franceschi G, Fumagalli L, Goel G, Hayton JA, Holdship C, Jiang Y, Jin D, Kapil V, Kavokine N, Koga K, Laage D, Lahav M, Miao S, Michaelides A, Mohandas N, Morgenstern K, Mukherjee T, Nagata Y, Olvera de la Cruz M, Pan D, Piaggi PM, Rempe SLB, Ryan P, Salzmann CG, Sayer T, Saykally RJ, Shepelenko M, Sosso GC, Whale TF, White JJ, Willard AP, Zhang P. Ice interfaces: general discussion. Faraday Discuss 2024; 249:133-161. [PMID: 38174608 DOI: 10.1039/d3fd90063k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
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6
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Franceschi G, Brandstetter S, Balajka J, Sokolović I, Pavelec J, Setvín M, Schmid M, Diebold U. Interaction of surface cations of cleaved mica with water in vapor and liquid forms. Faraday Discuss 2024; 249:84-97. [PMID: 37791454 PMCID: PMC10845011 DOI: 10.1039/d3fd00093a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/08/2023] [Indexed: 10/05/2023]
Abstract
Natural minerals contain ions that become hydrated when they come into contact with water in vapor and liquid forms. Muscovite mica - a common phyllosilicate with perfect cleavage planes - is an ideal system to investigate the details of ion hydration. The cleaved mica surface is decorated by an array of K+ ions that can be easily exchanged with other ions or protons when immersed in an aqueous solution. Despite the vast interest in the atomic-scale hydration processes of these K+ ions, experimental data under controlled conditions have remained elusive. Here, atomically resolved non-contact atomic force microscopy (nc-AFM) is combined with X-ray photoelectron spectroscopy (XPS) to investigate the cation hydration upon dosing water vapor at 100 K in ultra-high vacuum (UHV). The cleaved surface is further exposed to ultra-clean liquid water at room temperature, which promotes ion mobility and partial ion-to-proton substitution. The results offer the first direct experimental views of the interaction of water with muscovite mica under UHV. The findings are in line with previous theoretical predictions.
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Affiliation(s)
- Giada Franceschi
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Sebastian Brandstetter
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Jan Balajka
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Igor Sokolović
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Jiří Pavelec
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Martin Setvín
- Department of Surface and Plasma Science, Charles University in Prague, V Holesovickach 2, 180 00 Praha, Czech Republic
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria.
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7
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Franceschi G, Conti A, Lezuo L, Abart R, Mittendorfer F, Schmid M, Diebold U. How Water Binds to Microcline Feldspar (001). J Phys Chem Lett 2024; 15:15-22. [PMID: 38156776 PMCID: PMC10788961 DOI: 10.1021/acs.jpclett.3c03235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 01/03/2024]
Abstract
Microcline feldspar (KAlSi3O8) is a common mineral with important roles in Earth's ecological balance. It participates in carbon, potassium, and water cycles, contributing to CO2 sequestration, soil formation, and atmospheric ice nucleation. To understand the fundamentals of these processes, it is essential to establish microcline's surface atomic structure and its interaction with the omnipresent water molecules. This work presents atomic-scale results on microcline's lowest-energy surface and its interaction with water, combining ultrahigh vacuum investigations by noncontact atomic force microscopy and X-ray photoelectron spectroscopy with density functional theory calculations. An ordered array of hydroxyls bonded to silicon or aluminum readily forms on the cleaved surface at room temperature. The distinct proton affinities of these hydroxyls influence the arrangement and orientation of the first water molecules binding to the surface, holding potential implications for the subsequent condensation of water.
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Affiliation(s)
| | - Andrea Conti
- Institute
of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Luca Lezuo
- Institute
of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Rainer Abart
- Department
of Lithospheric Research, Universität
Wien, 1090 Vienna, Austria
| | | | - Michael Schmid
- Institute
of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, 1040 Vienna, Austria
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8
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Franceschi G, Heller R, Schmid M, Diebold U, Riva M. Evolution of the surface atomic structure of multielement oxide films: curse or blessing? Nanoscale Adv 2023; 5:7009-7017. [PMID: 38059015 PMCID: PMC10696924 DOI: 10.1039/d3na00847a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/02/2023] [Indexed: 12/08/2023]
Abstract
Atomically resolved scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) are used to gain atomic-scale insights into the heteroepitaxy of lanthanum-strontium manganite (LSMO, La1-xSrxMnO3-δ, x ≈ 0.2) on SrTiO3(110). LSMO is a perovskite oxide characterized by several composition-dependent surface reconstructions. The flexibility of the surface allows it to incorporate nonstoichiometries during growth, which causes the structure of the surface to evolve accordingly. This happens up to a critical point, where phase separation occurs, clusters rich in the excess cations form at the surface, and films show a rough morphology. To limit the nonstoichiometry introduced by non-optimal growth conditions, it proves useful to monitor the changes in surface atomic structures as a function of the PLD parameters and tune the latter accordingly.
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Affiliation(s)
- Giada Franceschi
- Institute of Applied Physics, TU Wien Wiedner Hauptstraβe 8-10/E134 1040 Vienna Austria
| | - Renè Heller
- Institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400 01328 Dresden Germany
| | - Michael Schmid
- Institute of Applied Physics, TU Wien Wiedner Hauptstraβe 8-10/E134 1040 Vienna Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien Wiedner Hauptstraβe 8-10/E134 1040 Vienna Austria
| | - Michele Riva
- Institute of Applied Physics, TU Wien Wiedner Hauptstraβe 8-10/E134 1040 Vienna Austria
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9
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Gericke SM, Kauppinen MM, Wagner M, Riva M, Franceschi G, Posada-Borbón A, Rämisch L, Pfaff S, Rheinfrank E, Imre AM, Preobrajenski AB, Appelfeller S, Blomberg S, Merte LR, Zetterberg J, Diebold U, Grönbeck H, Lundgren E. Effect of Different In 2O 3(111) Surface Terminations on CO 2 Adsorption. ACS Appl Mater Interfaces 2023; 15:45367-45377. [PMID: 37704018 PMCID: PMC10540140 DOI: 10.1021/acsami.3c07166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/07/2023] [Indexed: 09/15/2023]
Abstract
In2O3-based catalysts have shown high activity and selectivity for CO2 hydrogenation to methanol; however, the origin of the high performance of In2O3 is still unclear. To elucidate the initial steps of CO2 hydrogenation over In2O3, we have combined X-ray photoelectron spectroscopy and density functional theory calculations to study the adsorption of CO2 on the In2O3(111) crystalline surface with different terminations, namely, the stoichiometric, reduced, and hydroxylated surface. The combined approach confirms that the reduction of the surface results in the formation of In adatoms and that water dissociates on the surface at room temperature. A comparison of the experimental spectra and the computed core-level shifts (using methanol and formic acid as benchmark molecules) suggests that CO2 adsorbs as a carbonate on all three surface terminations. We find that the adsorption of CO2 is hindered by hydroxyl groups on the hydroxylated surface.
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Affiliation(s)
| | - Minttu M. Kauppinen
- Department
of Physics and Competence Centre for Catalysis, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Margareta Wagner
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | - Michele Riva
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | - Giada Franceschi
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | - Alvaro Posada-Borbón
- Department
of Physics and Competence Centre for Catalysis, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Lisa Rämisch
- Division
of Combustion Physics, Lund University, 22100 Lund, Sweden
| | - Sebastian Pfaff
- Division
of Combustion Physics, Lund University, 22100 Lund, Sweden
| | - Erik Rheinfrank
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | - Alexander M. Imre
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | | | | | - Sara Blomberg
- Department
of Chemical Engineering, Lund University, 22100 Lund, Sweden
| | - Lindsay R. Merte
- Department
of Materials Science and Applied Mathematics, Malmö University, 20506 Malmö, Sweden
| | - Johan Zetterberg
- Division
of Combustion Physics, Lund University, 22100 Lund, Sweden
| | - Ulrike Diebold
- Institute
of Applied Physics, Technische Universität
Wien, 1040 Vienna, Austria
| | - Henrik Grönbeck
- Department
of Physics and Competence Centre for Catalysis, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Edvin Lundgren
- Division
of Synchrotron Radiation Research, Lund
University, 22100 Lund, Sweden
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10
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Puntscher L, Sombut P, Wang C, Ulreich M, Pavelec J, Rafsanjani-Abbasi A, Meier M, Lagin A, Setvin M, Diebold U, Franchini C, Schmid M, Parkinson GS. A Multitechnique Study of C 2H 4 Adsorption on Fe 3O 4(001). J Phys Chem C Nanomater Interfaces 2023; 127:18378-18388. [PMID: 37752903 PMCID: PMC10518864 DOI: 10.1021/acs.jpcc.3c03684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/12/2023] [Indexed: 09/28/2023]
Abstract
The adsorption/desorption of ethene (C2H4), also commonly known as ethylene, on Fe3O4(001) was studied under ultrahigh vacuum conditions using temperature-programmed desorption (TPD), scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT)-based computations. To interpret the TPD data, we have employed a new analysis method based on equilibrium thermodynamics. C2H4 adsorbs intact at all coverages and interacts most strongly with surface defects such as antiphase domain boundaries and Fe adatoms. On the regular surface, C2H4 binds atop surface Fe sites up to a coverage of 2 molecules per (√2 × √2)R45° unit cell, with every second Fe occupied. A desorption energy of 0.36 eV is determined by analysis of the TPD spectra at this coverage, which is approximately 0.1-0.2 eV lower than the value calculated by DFT + U with van der Waals corrections. Additional molecules are accommodated in between the Fe rows. These are stabilized by attractive interactions with the molecules adsorbed at Fe sites. The total capacity of the surface for C2H4 adsorption is found to be close to 4 molecules per (√2 × √2)R45° unit cell.
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Affiliation(s)
- Lena Puntscher
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | | | - Chunlei Wang
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | - Manuel Ulreich
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | - Jiri Pavelec
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | | | - Matthias Meier
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
- Faculty
of Physics, Center for Computational Materials Science, University of Vienna, Vienna 1090, Austria
| | - Adam Lagin
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | - Martin Setvin
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
- Department
of Surface and Plasma Science, Faculty of
Mathematics and Physics, Charles University, Prague 180 00, Czech Republic
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
| | - Cesare Franchini
- Faculty
of Physics, Center for Computational Materials Science, University of Vienna, Vienna 1090, Austria
- Dipartimento
di Fisica e Astronomia, Università
di Bologna, Bologna 40126, Italy
| | - Michael Schmid
- Institute
of Applied Physics, TU Wien, Vienna 1040, Austria
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11
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Schmid M, Rath D, Diebold U. Correction to "Why and How Savitzky-Golay Filters Should Be Replaced". ACS Meas Sci Au 2023; 3:236. [PMID: 37360036 PMCID: PMC10288600 DOI: 10.1021/acsmeasuresciau.3c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Indexed: 06/28/2023]
Abstract
[This corrects the article DOI: 10.1021/acsmeasuresciau.1c00054.].
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12
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Kraushofer F, Meier M, Jakub Z, Hütner J, Balajka J, Hulva J, Schmid M, Franchini C, Diebold U, Parkinson GS. Oxygen-Terminated (1 × 1) Reconstruction of Reduced Magnetite Fe 3O 4(111). J Phys Chem Lett 2023; 14:3258-3265. [PMID: 36976170 PMCID: PMC10084462 DOI: 10.1021/acs.jpclett.3c00281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
The (111) facet of magnetite (Fe3O4) has been studied extensively by experimental and theoretical methods, but controversy remains regarding the structure of its low-energy surface terminations. Using density functional theory (DFT) computations, we demonstrate three reconstructions that are more favorable than the accepted Feoct2 termination under reducing conditions. All three structures change the coordination of iron in the kagome Feoct1 layer to be tetrahedral. With atomically resolved microscopy techniques, we show that the termination that coexists with the Fetet1 termination consists of tetrahedral iron capped by 3-fold coordinated oxygen atoms. This structure explains the inert nature of the reduced patches.
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Affiliation(s)
- Florian Kraushofer
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Matthias Meier
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
- University
of Vienna, Faculty of Physics and Center
for Computational Materials Science, 1090 Wien, Austria
| | - Zdeněk Jakub
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Johanna Hütner
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Jan Balajka
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Jan Hulva
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Michael Schmid
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Cesare Franchini
- University
of Vienna, Faculty of Physics and Center
for Computational Materials Science, 1090 Wien, Austria
- Alma
Mater Studiorum, Università di Bologna, 40127 Bologna, Italy
| | - Ulrike Diebold
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Gareth S. Parkinson
- Institute
of Applied Physics, Technische Universität
Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
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13
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Puntscher L, Daninger K, Schmid M, Diebold U, Parkinson GS. A study of Pt, Rh, Ni and Ir dispersion on anatase TiO2(101) and the role of water. Electrochim Acta 2023. [DOI: 10.1016/j.electacta.2023.142190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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14
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Corrias M, Papa L, Sokolović I, Birschitzky V, Gorfer A, Setvin M, Schmid M, Diebold U, Reticcioli M, Franchini C. Automated Real-Space Lattice Extraction for Atomic Force Microscopy Images. Mach Learn : Sci Technol 2023. [DOI: 10.1088/2632-2153/acb5e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Abstract
Analyzing atomically resolved images is a time-consuming process requiring solid experience and substantial human intervention. In addition, the acquired images contain a large amount of information such as crystal structure, presence and distribution of defects, and formation of domains, which need to be resolved to understand a material's surface structure. Therefore, machine learning techniques have been applied in scanning probe and electron microscopies during the last years, aiming for automatized and efficient image analysis. This work introduces a free and open source tool (AiSurf: Automated Identification of Surface Images) developed to inspect atomically resolved images via Scale-Invariant Feature Transform (SIFT) and Clustering Algorithms (CA). AiSurf extracts primitive lattice vectors, unit cells, and structural distortions from the original image, with no pre-assumption on the lattice and minimal user intervention. The method is applied to various atomically resolved non-contact atomic force microscopy (AFM) images of selected surfaces with different levels of complexity: anatase TiO2(101), oxygen deficient rutile TiO2(110) with and without CO adsorbates, SrTiO3(001) with Sr vacancies and graphene with C vacancies. The code delivers excellent results and is tested against atom misclassification and artifacts, thereby facilitating the interpretation of scanning probe microscopy images.
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15
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Franceschi G, Kocán P, Conti A, Brandstetter S, Balajka J, Sokolović I, Valtiner M, Mittendorfer F, Schmid M, Setvín M, Diebold U. Resolving the intrinsic short-range ordering of K + ions on cleaved muscovite mica. Nat Commun 2023; 14:208. [PMID: 36639388 PMCID: PMC9839703 DOI: 10.1038/s41467-023-35872-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
Muscovite mica, KAl2(Si3Al)O10(OH)2, is a common layered phyllosilicate with perfect cleavage planes. The atomically flat surfaces obtained through cleaving lend themselves to scanning probe techniques with atomic resolution and are ideal to model minerals and clays. Despite the importance of the cleaved mica surfaces, several questions remain unresolved. It is established that K+ ions decorate the cleaved surface, but their intrinsic ordering - unaffected by the interaction with the environment - is not known. This work presents clear images of the K+ distribution of cleaved mica obtained with low-temperature non-contact atomic force microscopy (AFM) under ultra-high vacuum (UHV) conditions. The data unveil the presence of short-range ordering, contrasting previous assumptions of random or fully ordered distributions. Density functional theory (DFT) calculations and Monte Carlo simulations show that the substitutional subsurface Al3+ ions have an important role for the surface K+ ion arrangement.
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Affiliation(s)
- Giada Franceschi
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Pavel Kocán
- grid.4491.80000 0004 1937 116XDepartment of Surface and Plasma Science, Charles University, V Holesovickach 2, 180 00 Prague, Czech Republic
| | - Andrea Conti
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Sebastian Brandstetter
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Jan Balajka
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Igor Sokolović
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Markus Valtiner
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Florian Mittendorfer
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Michael Schmid
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
| | - Martin Setvín
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria ,grid.4491.80000 0004 1937 116XDepartment of Surface and Plasma Science, Charles University, V Holesovickach 2, 180 00 Prague, Czech Republic
| | - Ulrike Diebold
- grid.5329.d0000 0001 2348 4034Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Vienna, Austria
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16
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Chen H, Blatnik MA, Ritterhoff CL, Sokolović I, Mirabella F, Franceschi G, Riva M, Schmid M, Čechal J, Meyer B, Diebold U, Wagner M. Water Structures Reveal Local Hydrophobicity on the In 2O 3(111) Surface. ACS Nano 2022; 16:21163-21173. [PMID: 36449748 PMCID: PMC9798908 DOI: 10.1021/acsnano.2c09115] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Clean oxide surfaces are generally hydrophilic. Water molecules anchor at undercoordinated surface metal atoms that act as Lewis acid sites, and they are stabilized by H bonds to undercoordinated surface oxygens. The large unit cell of In2O3(111) provides surface atoms in various configurations, which leads to chemical heterogeneity and a local deviation from this general rule. Experiments (TPD, XPS, nc-AFM) agree quantitatively with DFT calculations and show a series of distinct phases. The first three water molecules dissociate at one specific area of the unit cell and desorb above room temperature. The next three adsorb as molecules in the adjacent region. Three more water molecules rearrange this structure and an additional nine pile up above the OH groups. Despite offering undercoordinated In and O sites, the rest of the unit cell is unfavorable for adsorption and remains water-free. The first water layer thus shows ordering into nanoscopic 3D water clusters separated by hydrophobic pockets.
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Affiliation(s)
- Hao Chen
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
- State
Key Laboratory of Catalysis, Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China
- University
of the Chinese Academy of Sciences, Beijing100049, China
| | - Matthias A. Blatnik
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
- Central
European Institute of Technology (CEITEC), Brno University of Technology, 61200Brno, Czech
Republic
| | - Christian L. Ritterhoff
- Interdisciplinary
Center for Molecular Materials (ICMM) and Computer Chemistry Center
(CCC), Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), 91052Erlangen, Germany
| | - Igor Sokolović
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
| | | | | | - Michele Riva
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
| | - Michael Schmid
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
| | - Jan Čechal
- Central
European Institute of Technology (CEITEC), Brno University of Technology, 61200Brno, Czech
Republic
| | - Bernd Meyer
- Interdisciplinary
Center for Molecular Materials (ICMM) and Computer Chemistry Center
(CCC), Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), 91052Erlangen, Germany
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
| | - Margareta Wagner
- Institute
of Applied Physics, TU Wien, 1040Vienna, Austria
- Central
European Institute of Technology (CEITEC), Brno University of Technology, 61200Brno, Czech
Republic
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17
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Schmid M, Parkinson GS, Diebold U. Analysis of Temperature-Programmed Desorption via Equilibrium Thermodynamics. ACS Phys Chem Au 2022; 3:44-62. [PMID: 36718262 PMCID: PMC9881163 DOI: 10.1021/acsphyschemau.2c00031] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/16/2022]
Abstract
Temperature-programmed desorption (TPD) experiments in surface science are usually analyzed using the Polanyi-Wigner equation and/or transition-state theory. These methods are far from straightforward, and the determination of the pre-exponential factor is often problematic. We present a different method based on equilibrium thermodynamics, which builds on an approach previously used for TPD by Kreuzer et al. (Surf. Sci. 1988). Equations for the desorption rate are presented for three different types of surface-adsorbate interactions: (i) a 2D ideal hard-sphere gas with a negligible diffusion barrier, (ii) an ideal lattice gas, that is, fixed adsorption sites without interaction between the adsorbates, and (iii) a lattice gas with a distribution of (site-dependent) adsorption energies. We show that the coverage dependence of the sticking coefficient for adsorption at the desorption temperature determines whether the desorption process can be described by first- or second-order kinetics. The sticking coefficient at the desorption temperature must also be known for a quantitative determination of the adsorption energy, but it has a rather weak influence (like the pre-exponential factor in a traditional TPD analysis). Quantitative analysis is also influenced by the vibrational contributions to the energy and entropy. For the case of a single adsorption energy, we provide equations to directly convert peak temperatures into adsorption energies. These equations also provide an approximation of the desorption energy in cases that cannot be described by a fixed pre-exponential factor. For the case of a distribution of adsorption energies, the desorption spectra cannot be considered a superposition of desorption spectra corresponding to the different energies. Nevertheless, we present a method to extract the distribution of adsorption energies from TPD spectra, and we rationalize the energy resolution of TPD experiments. The analytical results are complemented by a program for simulation and analysis of TPD data.
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18
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Wang Z, Reticcioli M, Jakub Z, Sokolović I, Meier M, Boatner LA, Schmid M, Parkinson GS, Diebold U, Franchini C, Setvin M. Surface chemistry on a polarizable surface: Coupling of CO with KTaO 3(001). Sci Adv 2022; 8:eabq1433. [PMID: 35984882 PMCID: PMC9390988 DOI: 10.1126/sciadv.abq1433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Polarizable materials attract attention in catalysis because they have a free parameter for tuning chemical reactivity. Their surfaces entangle the dielectric polarization with surface polarity, excess charge, and orbital hybridization. How this affects individual adsorbed molecules is shown for the incipient ferroelectric perovskite KTaO3. This intrinsically polar material cleaves along (001) into KO- and TaO2-terminated surface domains. At TaO2 terraces, the polarity-compensating excess electrons form a two-dimensional electron gas and can also localize by coupling to ferroelectric distortions. TaO2 terraces host two distinct types of CO molecules, adsorbed at equivalent lattice sites but charged differently as seen in atomic force microscopy/scanning tunneling microscopy. Temperature-programmed desorption shows substantially stronger binding of the charged CO; in density functional theory calculations, the excess charge favors a bipolaronic configuration coupled to the CO. These results pinpoint how adsorption states couple to ferroelectric polarization.
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Affiliation(s)
- Zhichang Wang
- Institute of Applied Physics, TU Wien, Vienna, Austria
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Michele Reticcioli
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, Vienna, Austria
| | - Zdenek Jakub
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | | | - Lynn A. Boatner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | | | | | - Cesare Franchini
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, Vienna, Austria
- Dipartimento di Fisica e Astronomia, Universita di Bologna, 40127 Bologna, Italy
| | - Martin Setvin
- Institute of Applied Physics, TU Wien, Vienna, Austria
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8, Czech Republic
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19
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Reticcioli M, Wang Z, Schmid M, Wrana D, Boatner LA, Diebold U, Setvin M, Franchini C. Competing electronic states emerging on polar surfaces. Nat Commun 2022; 13:4311. [PMID: 35879300 PMCID: PMC9314351 DOI: 10.1038/s41467-022-31953-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 07/07/2022] [Indexed: 11/28/2022] Open
Abstract
Excess charge on polar surfaces of ionic compounds is commonly described by the two-dimensional electron gas (2DEG) model, a homogeneous distribution of charge, spatially-confined in a few atomic layers. Here, by combining scanning probe microscopy with density functional theory calculations, we show that excess charge on the polar TaO2 termination of KTaO3(001) forms more complex electronic states with different degrees of spatial and electronic localization: charge density waves (CDW) coexist with strongly-localized electron polarons and bipolarons. These surface electronic reconstructions, originating from the combined action of electron-lattice interaction and electronic correlation, are energetically more favorable than the 2DEG solution. They exhibit distinct spectroscopy signals and impact on the surface properties, as manifested by a local suppression of ferroelectric distortions. Defect-free surfaces with excess charge are typically described as a homogeneous 2D electron gas. Here, in contrast, the authors find that the KTaO3(001) surface hosts a charge density wave coexisting with a pattern of electron polarons, highly localized states of excess electrons bound to a lattice distortion.
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Affiliation(s)
- Michele Reticcioli
- University of Vienna, Faculty of Physics, Center for Computational Materials Science, Vienna, Austria.,Institute of Applied Physics, Technische Universität Wien, Vienna, Austria
| | - Zhichang Wang
- Institute of Applied Physics, Technische Universität Wien, Vienna, Austria.,State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, Vienna, Austria
| | - Dominik Wrana
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00, Prague 8, Czech Republic
| | - Lynn A Boatner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, Vienna, Austria
| | - Martin Setvin
- Institute of Applied Physics, Technische Universität Wien, Vienna, Austria. .,Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00, Prague 8, Czech Republic.
| | - Cesare Franchini
- University of Vienna, Faculty of Physics, Center for Computational Materials Science, Vienna, Austria. .,Dipartimento di Fisica e Astronomia, Università di Bologna, 40127, Bologna, Italy.
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20
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Merte LR, Bisbo MK, Sokolović I, Setvín M, Hagman B, Shipilin M, Schmid M, Diebold U, Lundgren E, Hammer B. Structure of an Ultrathin Oxide on Pt 3 Sn(111) Solved by Machine Learning Enhanced Global Optimization. Angew Chem Int Ed Engl 2022; 61:e202204244. [PMID: 35384213 PMCID: PMC9320988 DOI: 10.1002/anie.202204244] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 11/07/2022]
Abstract
Determination of the atomic structure of solid surfaces typically depends on comparison of measured properties with simulations based on hypothesized structural models. For simple structures, the models may be guessed, but for more complex structures there is a need for reliable theory-based search algorithms. So far, such methods have been limited by the combinatorial complexity and computational expense of sufficiently accurate energy estimation for surfaces. However, the introduction of machine learning methods has the potential to change this radically. Here, we demonstrate how an evolutionary algorithm, utilizing machine learning for accelerated energy estimation and diverse population generation, can be used to solve an unknown surface structure-the (4×4) surface oxide on Pt3 Sn(111)-based on limited experimental input. The algorithm is efficient and robust, and should be broadly applicable in surface studies, where it can replace manual, intuition based model generation.
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Affiliation(s)
- Lindsay R Merte
- Materials Science and Applied Mathematics, Malmö University, 20506, Malmö, Sweden
| | - Malthe Kjaer Bisbo
- Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, 8000, Aarhus, Denmark
| | - Igor Sokolović
- Institute of Applied Physics, TU Wien, 1040, Vienna, Austria
| | - Martin Setvín
- Institute of Applied Physics, TU Wien, 1040, Vienna, Austria.,Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00, Prague 8, Czech Republic
| | - Benjamin Hagman
- Div. of Synchrotron Radiation Research, Lund University, 22100, Lund, Sweden
| | - Mikhail Shipilin
- Div. of Synchrotron Radiation Research, Lund University, 22100, Lund, Sweden
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, 1040, Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, 1040, Vienna, Austria
| | - Edvin Lundgren
- Div. of Synchrotron Radiation Research, Lund University, 22100, Lund, Sweden
| | - Bjørk Hammer
- Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, 8000, Aarhus, Denmark
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21
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Merte LR, Bisbo MK, Sokolović I, Setvín M, Hagman B, Shipilin M, Schmid M, Diebold U, Lundgren E, Hammer B. Structure of an Ultrathin Oxide on Pt 3Sn(111) Solved by Machine Learning Enhanced Global Optimization. Angew Chem Weinheim Bergstr Ger 2022; 134:e202204244. [PMID: 38505419 PMCID: PMC10946564 DOI: 10.1002/ange.202204244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 11/09/2022]
Abstract
Determination of the atomic structure of solid surfaces typically depends on comparison of measured properties with simulations based on hypothesized structural models. For simple structures, the models may be guessed, but for more complex structures there is a need for reliable theory-based search algorithms. So far, such methods have been limited by the combinatorial complexity and computational expense of sufficiently accurate energy estimation for surfaces. However, the introduction of machine learning methods has the potential to change this radically. Here, we demonstrate how an evolutionary algorithm, utilizing machine learning for accelerated energy estimation and diverse population generation, can be used to solve an unknown surface structure-the (4×4) surface oxide on Pt3Sn(111)-based on limited experimental input. The algorithm is efficient and robust, and should be broadly applicable in surface studies, where it can replace manual, intuition based model generation.
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Affiliation(s)
- Lindsay R. Merte
- Materials Science and Applied MathematicsMalmö University20506MalmöSweden
| | - Malthe Kjær Bisbo
- Center for Interstellar CatalysisDepartment of Physics and AstronomyAarhus University8000AarhusDenmark
| | | | - Martin Setvín
- Institute of Applied PhysicsTU Wien1040ViennaAustria
- Department of Surface and Plasma ScienceFaculty of Mathematics and PhysicsCharles University180 00Prague 8Czech Republic
| | - Benjamin Hagman
- Div. of Synchrotron Radiation ResearchLund University22100LundSweden
| | - Mikhail Shipilin
- Div. of Synchrotron Radiation ResearchLund University22100LundSweden
| | | | | | - Edvin Lundgren
- Div. of Synchrotron Radiation ResearchLund University22100LundSweden
| | - Bjørk Hammer
- Center for Interstellar CatalysisDepartment of Physics and AstronomyAarhus University8000AarhusDenmark
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22
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Schmid M, Rath D, Diebold U. Why and How Savitzky-Golay Filters Should Be Replaced. ACS Meas Sci Au 2022; 2:185-196. [PMID: 35479103 PMCID: PMC9026279 DOI: 10.1021/acsmeasuresciau.1c00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Savitzky-Golay (SG) filtering, based on local least-squares fitting of the data by polynomials, is a popular method for smoothing data and calculations of derivatives of noisy data. At frequencies above the cutoff, SG filters have poor noise suppression; this unnecessarily reduces the signal-to-noise ratio, especially when calculating derivatives of the data. In addition, SG filtering near the boundaries of the data range is prone to artifacts, which are especially strong when using SG filters for calculating derivatives of the data. We show how these disadvantages can be avoided while keeping the advantageous properties of SG filters. We present two classes of finite impulse response (FIR) filters with substantially improved frequency response: (i) SG filters with fitting weights in the shape of a window function and (ii) convolution kernels based on the sinc function with a Gaussian-like window function and additional corrections for improving the frequency response in the passband (modified sinc kernel). Compared with standard SG filters, the only price to pay for the improvement is a moderate increase in the kernel size. Smoothing at the boundaries of the data can be improved with a non-FIR method, the Whittaker-Henderson smoother, or by linear extrapolation of the data, followed by convolution with a modified sinc kernel, and we show that the latter is preferable in most cases. We provide computer programs and equations for the smoothing parameters of these smoothers when used as plug-in replacements for SG filters and describe how to choose smoothing parameters to preserve peak heights in spectra.
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23
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Meier M, Hulva J, Jakub Z, Kraushofer F, Bobić M, Bliem R, Setvin M, Schmid M, Diebold U, Franchini C, Parkinson GS. CO oxidation by Pt 2/Fe 3O 4: Metastable dimer and support configurations facilitate lattice oxygen extraction. Sci Adv 2022; 8:eabn4580. [PMID: 35363523 PMCID: PMC10938578 DOI: 10.1126/sciadv.abn4580] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Heterogeneous catalysts based on subnanometer metal clusters often exhibit strongly size-dependent properties, and the addition or removal of a single atom can make all the difference. Identifying the most active species and deciphering the reaction mechanism is extremely difficult, however, because it is often not clear how the catalyst evolves in operando. Here, we use a combination of atomically resolved scanning probe microscopies, spectroscopic techniques, and density functional theory (DFT)-based calculations to study CO oxidation by a model Pt/Fe3O4(001) "single-atom" catalyst. We demonstrate that (PtCO)2 dimers, formed dynamically through the agglomeration of mobile Pt-carbonyl species, catalyze a reaction involving the oxide support to form CO2. Pt2 dimers produce one CO2 molecule before falling apart into two adatoms, releasing the second CO. Olattice extraction only becomes facile when both the Pt-dimer and the Fe3O4 support can access metastable configurations, suggesting that substantial, concerted rearrangements of both cluster and support must be considered for reactions occurring at elevated temperature.
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Affiliation(s)
- Matthias Meier
- Institute of Applied Physics, TU Wien, Vienna, Austria
- Computational Materials Physics, University of Vienna, Vienna, Austria
| | - Jan Hulva
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Zdenek Jakub
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | - Mislav Bobić
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Roland Bliem
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Martin Setvin
- Institute of Applied Physics, TU Wien, Vienna, Austria
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | | | | | - Cesare Franchini
- Computational Materials Physics, University of Vienna, Vienna, Austria
- Alma Mater Studiorum – Università di Bologna, Bologna, Italy
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24
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Reticcioli M, Diebold U, Franchini C. Modeling polarons in density functional theory: lessons learned from TiO 2. J Phys Condens Matter 2022; 34:204006. [PMID: 35213845 DOI: 10.1088/1361-648x/ac58d7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Density functional theory (DFT) is nowadays one of the most broadly used and successful techniques to study the properties of polarons and their effects in materials. Here, we systematically analyze the aspects of the theoretical calculations that are crucial to obtain reliable predictions in agreement with the experimental observations. We focus on rutile TiO2, a prototypical polaronic compound, and compare the formation of polarons on the (110) surface and subsurface atomic layers. As expected, the parameterUused to correct the electronic correlation in the DFT +Uformalism affects the resulting charge localization, local structural distortions and electronic properties of polarons. Moreover, the polaron localization can be driven to different sites by strain: due to different local environments, surface and subsurface polarons show different responses to the applied strain, with impact on the relative energy stability. An accurate description of the properties of polarons is key to understand their impact on complex phenomena and applications: as an example, we show the effects of lattice strain on the interaction between polarons and CO adsorbates.
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Affiliation(s)
- Michele Reticcioli
- University of Vienna, Faculty of Physics, Center for Computational Materials Science, Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, Vienna, Austria
| | - Cesare Franchini
- University of Vienna, Faculty of Physics, Center for Computational Materials Science, Vienna, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
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25
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Kraushofer F, Haager L, Eder M, Rafsanjani-Abbasi A, Jakub Z, Franceschi G, Riva M, Meier M, Schmid M, Diebold U, Parkinson GS. Single Rh Adatoms Stabilized on α-Fe 2O 3(11̅02) by Coadsorbed Water. ACS Energy Lett 2022; 7:375-380. [PMID: 35059503 PMCID: PMC8762699 DOI: 10.1021/acsenergylett.1c02405] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Oxide-supported single-atom catalysts are commonly modeled as a metal atom substituting surface cation sites in a low-index surface. Adatoms with dangling bonds will inevitably coordinate molecules from the gas phase, and adsorbates such as water can affect both stability and catalytic activity. Herein, we use scanning tunneling microscopy (STM), noncontact atomic force microscopy (ncAFM), and X-ray photoelectron spectroscopy (XPS) to show that high densities of single Rh adatoms are stabilized on α-Fe2O3(11̅02) in the presence of 2 × 10-8 mbar of water at room temperature, in marked contrast to the rapid sintering observed under UHV conditions. Annealing to 50 °C in UHV desorbs all water from the substrate leaving only the OH groups coordinated to Rh, and high-resolution ncAFM images provide a direct view into the internal structure. We provide direct evidence of the importance of OH ligands in the stability of single atoms and argue that their presence should be assumed when modeling single-atom catalysis systems.
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Affiliation(s)
- Florian Kraushofer
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Lena Haager
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Moritz Eder
- Chair
of Physical Chemistry & Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Ali Rafsanjani-Abbasi
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Zdeněk Jakub
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Giada Franceschi
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Michele Riva
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Matthias Meier
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Michael Schmid
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Gareth S. Parkinson
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
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26
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Jakub Z, Meier M, Kraushofer F, Balajka J, Pavelec J, Schmid M, Franchini C, Diebold U, Parkinson GS. Rapid oxygen exchange between hematite and water vapor. Nat Commun 2021; 12:6488. [PMID: 34759277 PMCID: PMC8580966 DOI: 10.1038/s41467-021-26601-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 10/13/2021] [Indexed: 11/14/2022] Open
Abstract
Oxygen exchange at oxide/liquid and oxide/gas interfaces is important in technology and environmental studies, as it is closely linked to both catalytic activity and material degradation. The atomic-scale details are mostly unknown, however, and are often ascribed to poorly defined defects in the crystal lattice. Here we show that even thermodynamically stable, well-ordered surfaces can be surprisingly reactive. Specifically, we show that all the 3-fold coordinated lattice oxygen atoms on a defect-free single-crystalline "r-cut" ([Formula: see text]) surface of hematite (α-Fe2O3) are exchanged with oxygen from surrounding water vapor within minutes at temperatures below 70 °C, while the atomic-scale surface structure is unperturbed by the process. A similar behavior is observed after liquid-water exposure, but the experimental data clearly show most of the exchange happens during desorption of the final monolayer, not during immersion. Density functional theory computations show that the exchange can happen during on-surface diffusion, where the cost of the lattice oxygen extraction is compensated by the stability of an HO-HOH-OH complex. Such insights into lattice oxygen stability are highly relevant for many research fields ranging from catalysis and hydrogen production to geochemistry and paleoclimatology.
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Affiliation(s)
- Zdenek Jakub
- Institute of Applied Physics, TU Wien, Vienna, Austria
- Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, Czech Republic
| | - Matthias Meier
- Institute of Applied Physics, TU Wien, Vienna, Austria
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna, Austria
| | | | - Jan Balajka
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Jiri Pavelec
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | - Cesare Franchini
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna, Austria
- Alma Mater Studiorum-Università di Bologna, Bologna, Italy
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27
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Wagner M, Meyer B, Setvin M, Schmid M, Diebold U. Direct assessment of the acidity of individual surface hydroxyls. Nature 2021; 592:722-725. [PMID: 33911267 DOI: 10.1038/s41586-021-03432-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/08/2021] [Indexed: 11/10/2022]
Abstract
The state of deprotonation/protonation of surfaces has far-ranging implications in chemistry, from acid-base catalysis1 and the electrocatalytic and photocatalytic splitting of water2, to the behaviour of minerals3 and biochemistry4. An entity's acidity is described by its proton affinity and its acid dissociation constant pKa (the negative logarithm of the equilibrium constant of the proton transfer reaction in solution). The acidity of individual sites is difficult to assess for solids, compared with molecules. For mineral surfaces, the acidity is estimated by semi-empirical concepts, such as bond-order valence sums5, and increasingly modelled with first-principles molecular dynamics simulations6,7. At present, such predictions cannot be tested-experimental measures, such as the point of zero charge8, integrate over the whole surface or, in some cases, individual crystal facets9. Here we assess the acidity of individual hydroxyl groups on In2O3(111)-a model oxide with four different types of surface oxygen atom. We probe the strength of their hydrogen bonds with the tip of a non-contact atomic force microscope and find quantitative agreement with density functional theory calculations. By relating the results to known proton affinities of gas-phase molecules, we determine the proton affinity of the different surface sites of In2O3 with atomic precision. Measurements on hydroxylated titanium dioxide and zirconium oxide extend our method to other oxides.
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Affiliation(s)
- Margareta Wagner
- Institute of Applied Physics, TU Wien, Vienna, Austria.,Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, Czech Republic
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Computer Chemistry Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Martin Setvin
- Institute of Applied Physics, TU Wien, Vienna, Austria.,Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
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28
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Hulva J, Meier M, Bliem R, Jakub Z, Kraushofer F, Schmid M, Diebold U, Franchini C, Parkinson GS. Unraveling CO adsorption on model single-atom catalysts. Science 2021; 371:375-379. [PMID: 33479148 DOI: 10.1126/science.abe5757] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/09/2020] [Indexed: 12/16/2022]
Abstract
Understanding how the local environment of a "single-atom" catalyst affects stability and reactivity remains a challenge. We present an in-depth study of copper1, silver1, gold1, nickel1, palladium1, platinum1, rhodium1, and iridium1 species on Fe3O4(001), a model support in which all metals occupy the same twofold-coordinated adsorption site upon deposition at room temperature. Surface science techniques revealed that CO adsorption strength at single metal sites differs from the respective metal surfaces and supported clusters. Charge transfer into the support modifies the d-states of the metal atom and the strength of the metal-CO bond. These effects could strengthen the bond (as for Ag1-CO) or weaken it (as for Ni1-CO), but CO-induced structural distortions reduce adsorption energies from those expected on the basis of electronic structure alone. The extent of the relaxations depends on the local geometry and could be predicted by analogy to coordination chemistry.
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Affiliation(s)
- Jan Hulva
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Matthias Meier
- Institute of Applied Physics, TU Wien, Vienna, Austria.,Computational Materials Physics, University of Vienna, Vienna, Austria
| | - Roland Bliem
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | - Zdenek Jakub
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | | | | | - Cesare Franchini
- Computational Materials Physics, University of Vienna, Vienna, Austria.,Alma Mater Studiorum-Università di Bologna, Bologna, Italy
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29
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Grumelli D, Wiegmann T, Barja S, Reikowski F, Maroun F, Allongue P, Balajka J, Parkinson GS, Diebold U, Kern K, Magnussen OM. Electrochemical Stability of the Reconstructed Fe 3 O 4 (001) Surface. Angew Chem Int Ed Engl 2020; 59:21904-21908. [PMID: 32729209 DOI: 10.1002/anie.202008785] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/24/2020] [Indexed: 11/11/2022]
Abstract
Establishing the atomic-scale structure of metal-oxide surfaces during electrochemical reactions is a key step to modeling this important class of electrocatalysts. Here, we demonstrate that the characteristic (√2×√2)R45° surface reconstruction formed on (001)-oriented magnetite single crystals is maintained after immersion in 0.1 M NaOH at 0.20 V vs. Ag/AgCl and we investigate its dependence on the electrode potential. We follow the evolution of the surface using in situ and operando surface X-ray diffraction from the onset of hydrogen evolution, to potentials deep in the oxygen evolution reaction (OER) regime. The reconstruction remains stable for hours between -0.20 and 0.60 V and, surprisingly, is still present at anodic current densities of up to 10 mA cm-2 and strongly affects the OER kinetics. We attribute this to a stabilization of the Fe3 O4 bulk by the reconstructed surface. At more negative potentials, a gradual and largely irreversible lifting of the reconstruction is observed due to the onset of oxide reduction.
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Affiliation(s)
- Doris Grumelli
- Instituto Nacional de Investigaciones Fisicoquimcas Teoricas y Aplicadas, Universidad Nacional de La Plata, CONICET, La Plata, Argentine
| | | | - Sara Barja
- Departamento de Física de Materiales, Centro de Física de Materiales, University of the Basque Country (UPV/EHU-CSIC), Donostia-San Sebastián, Spain.,Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | | | - Fouad Maroun
- Laboratoire de Physique de la Matière Condensée, CNRS, IP Paris, 91128, Palaiseau, France
| | - Philippe Allongue
- Laboratoire de Physique de la Matière Condensée, CNRS, IP Paris, 91128, Palaiseau, France
| | - Jan Balajka
- Institute of Applied Physics, TU Wien, Vienna, Austria
| | | | | | - Klaus Kern
- Max Planck Institute for Solid State Research, Stuttgart, Germany.,Ecole Polytechnique Fédérale de Lausanne, Switzerland
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30
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Grumelli D, Wiegmann T, Barja S, Reikowski F, Maroun F, Allongue P, Balajka J, Parkinson GS, Diebold U, Kern K, Magnussen OM. Electrochemical Stability of the Reconstructed Fe
3
O
4
(001) Surface. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Doris Grumelli
- Instituto Nacional de Investigaciones Fisicoquimcas Teoricas y Aplicadas Universidad Nacional de La Plata, CONICET La Plata Argentine
| | | | - Sara Barja
- Departamento de Física de Materiales Centro de Física de Materiales University of the Basque Country (UPV/EHU-CSIC) Donostia-San Sebastián Spain
- Donostia International Physics Center (DIPC) Donostia-San Sebastián Spain
- IKERBASQUE Basque Foundation for Science Bilbao Spain
| | | | - Fouad Maroun
- Laboratoire de Physique de la Matière Condensée CNRS, IP Paris 91128 Palaiseau France
| | - Philippe Allongue
- Laboratoire de Physique de la Matière Condensée CNRS, IP Paris 91128 Palaiseau France
| | - Jan Balajka
- Institute of Applied Physics TU Wien Vienna Austria
| | | | | | - Klaus Kern
- Max Planck Institute for Solid State Research Stuttgart Germany
- Ecole Polytechnique Fédérale de Lausanne Switzerland
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31
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Timmermann J, Kraushofer F, Resch N, Li P, Wang Y, Mao Z, Riva M, Lee Y, Staacke C, Schmid M, Scheurer C, Parkinson GS, Diebold U, Reuter K. IrO_{2} Surface Complexions Identified through Machine Learning and Surface Investigations. Phys Rev Lett 2020; 125:206101. [PMID: 33258623 DOI: 10.1103/physrevlett.125.206101] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/22/2020] [Indexed: 06/12/2023]
Abstract
A Gaussian approximation potential was trained using density-functional theory data to enable a global geometry optimization of low-index rutile IrO_{2} facets through simulated annealing. Ab initio thermodynamics identifies (101) and (111) (1×1) terminations competitive with (110) in reducing environments. Experiments on single crystals find that (101) facets dominate and exhibit the theoretically predicted (1×1) periodicity and x-ray photoelectron spectroscopy core-level shifts. The obtained structures are analogous to the complexions discussed in the context of ceramic battery materials.
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Affiliation(s)
- Jakob Timmermann
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, D-85747 Garching, Germany
| | - Florian Kraushofer
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Nikolaus Resch
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Peigang Li
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA
| | - Yu Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Zhiqiang Mao
- Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Michele Riva
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Yonghyuk Lee
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, D-85747 Garching, Germany
| | - Carsten Staacke
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, D-85747 Garching, Germany
| | - Michael Schmid
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Christoph Scheurer
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, D-85747 Garching, Germany
| | - Gareth S Parkinson
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, Technical University of Vienna, Wiedner Hauptstrasse 8-10/134, A-1040 Vienna, Austria
| | - Karsten Reuter
- Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstrasse 4, D-85747 Garching, Germany
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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32
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Mirabella F, Balajka J, Pavelec J, Göbel M, Kraushofer F, Schmid M, Parkinson GS, Diebold U. Atomic-Scale Studies of Fe 3 O 4 (001) and TiO 2 (110) Surfaces Following Immersion in CO 2 -Acidified Water. Chemphyschem 2020; 21:1788-1796. [PMID: 32639106 PMCID: PMC7522689 DOI: 10.1002/cphc.202000471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/30/2020] [Indexed: 12/02/2022]
Abstract
Difficulties associated with the integration of liquids into a UHV environment make surface-science style studies of mineral dissolution particularly challenging. Recently, we developed a novel experimental setup for the UHV-compatible dosing of ultrapure liquid water and studied its interaction with TiO2 and Fe3 O4 surfaces. Herein, we describe a simple approach to vary the pH through the partial pressure of CO2 ( p C O 2 ) in the surrounding vacuum chamber and use this to study how these surfaces react to an acidic solution. The TiO2 (110) surface is unaffected by the acidic solution, except for a small amount of carbonaceous contamination. The Fe3 O4 (001)-( 2 × 2 )R45° surface begins to dissolve at a pH 4.0-3.9 ( p C O 2 =0.8-1 bar) and, although it is significantly roughened, the atomic-scale structure of the Fe3 O4 (001) surface layer remains visible in scanning tunneling microscopy (STM) images. X-ray photoelectron spectroscopy (XPS) reveals that the surface is chemically reduced and contains a significant accumulation of bicarbonate (HCO3 - ) species. These observations are consistent with Fe(II) being extracted by bicarbonate ions, leading to dissolved iron bicarbonate complexes (Fe(HCO3 )2 ), which precipitate onto the surface when the water evaporates.
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Affiliation(s)
| | - Jan Balajka
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
- Department of Chemistry and Chemical BiologyCornell UniversityIthacaNY14853USA
| | - Jiri Pavelec
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
| | - Markus Göbel
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
| | - Florian Kraushofer
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
| | - Michael Schmid
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
| | | | - Ulrike Diebold
- Institut für Angewandte PhysikTechnische Universität Wien1040WienAustria
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33
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Baker LR, Diebold U, Park JY, Selloni A. Oxide chemistry and catalysis. J Chem Phys 2020; 153:050401. [DOI: 10.1063/5.0021819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- L. Robert Baker
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43221, USA
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Jeong Young Park
- Department of Chemistry, KAIST, Daejeon 34141, South Korea
- Center for Nanomaterials and Chemical Reactions, Institute for Basic Science, Daejeon 34141, South Korea
| | - Annabella Selloni
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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34
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Štubian M, Bobek J, Setvin M, Diebold U, Schmid M. Fast low-noise transimpedance amplifier for scanning tunneling microscopy and beyond. Rev Sci Instrum 2020; 91:074701. [PMID: 32752833 DOI: 10.1063/5.0011097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
A transimpedance amplifier has been designed for scanning tunneling microscopy (STM). The amplifier features low noise (limited by the Johnson noise of the 1 GΩ feedback resistor at low input current and low frequencies), sufficient bandwidth for most STM applications (50 kHz at 35 pF input capacitance), a large dynamic range (0.1 pA-50 nA without range switching), and a low input voltage offset. The amplifier is also suited for placing its first stage into the cryostat of a low-temperature STM, minimizing the input capacitance and reducing the Johnson noise of the feedback resistor. The amplifier may also find applications for specimen current imaging and electron-beam-induced current measurements in scanning electron microscopy and as a photodiode amplifier with a large dynamic range. This paper also discusses the sources of noise including the often neglected effect of non-balanced input impedance of operational amplifiers and describes how to accurately measure and adjust the frequency response of low-current transimpedance amplifiers.
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Affiliation(s)
- Martin Štubian
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Juraj Bobek
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Martin Setvin
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
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35
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Sokolović I, Reticcioli M, Čalkovský M, Wagner M, Schmid M, Franchini C, Diebold U, Setvín M. Resolving the adsorption of molecular O 2 on the rutile TiO 2(110) surface by noncontact atomic force microscopy. Proc Natl Acad Sci U S A 2020; 117:14827-14837. [PMID: 32527857 PMCID: PMC7334520 DOI: 10.1073/pnas.1922452117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interaction of molecular oxygen with semiconducting oxide surfaces plays a key role in many technologies. The topic is difficult to approach both by experiment and in theory, mainly due to multiple stable charge states, adsorption configurations, and reaction channels of adsorbed oxygen species. Here we use a combination of noncontact atomic force microscopy (AFM) and density functional theory (DFT) to resolve [Formula: see text] adsorption on the rutile [Formula: see text](110) surface, which presents a longstanding challenge in the surface chemistry of metal oxides. We show that chemically inert AFM tips terminated by an oxygen adatom provide excellent resolution of both the adsorbed species and the oxygen sublattice of the substrate. Adsorbed [Formula: see text] molecules can accept either one or two electron polarons from the surface, forming superoxo or peroxo species. The peroxo state is energetically preferred under any conditions relevant for applications. The possibility of nonintrusive imaging allows us to explain behavior related to electron/hole injection from the tip, interaction with UV light, and the effect of thermal annealing.
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Affiliation(s)
- Igor Sokolović
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Michele Reticcioli
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Center for Computational Materials Science, University of Vienna, 1090 Vienna, Austria
| | - Martin Čalkovský
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Institute of Physical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic
| | - Margareta Wagner
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Central European Institute of Technology, Brno University of Technology, 612 00 Brno, Czech Republic
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Cesare Franchini
- Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- Center for Computational Materials Science, University of Vienna, 1090 Vienna, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Martin Setvín
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria;
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00 Prague 8, Czech Republic
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36
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Franceschi G, Schmid M, Diebold U, Riva M. Movable holder for a quartz crystal microbalance for exact growth rates in pulsed laser deposition. Rev Sci Instrum 2020; 91:065003. [PMID: 32611011 DOI: 10.1063/5.0007643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
Controlling the amount of material deposited by pulsed laser deposition (PLD) down to fractions of one atomic layer is crucial for nanoscale technologies based on thin-film heterostructures. Albeit unsurpassed for measuring growth rates with high accuracy, the quartz crystal microbalance (QCM) suffers from some limitations when applied to PLD. The strong directionality of the PLD plasma plume and its pronounced dependence on deposition parameters (e.g., background pressure and fluence) require that the QCM is placed at the same position as the substrate during growth. However, QCM sensors are commonly fixed off to one side of the substrate. This also entails fast degradation of the crystal, as it is constantly exposed to the ablated material. The design for a movable QCM holder discussed in this work overcomes these issues. The holder is compatible with standard transfer arms, enabling easy insertion and transfer between a PLD chamber and other adjoining vacuum chambers. The QCM can be placed at the same position as the substrate during PLD growth. Its resonance frequency is measured in vacuum at any location where it can be in contact with an electrical feedthrough, before and after deposition. We tested the design for the deposition of hematite (Fe2O3), comparing the rates derived from the QCM and from reflection high-energy electron diffraction oscillations during homoepitaxial growth.
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Affiliation(s)
- Giada Franceschi
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
| | - Michele Riva
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/E134, 1040 Wien, Austria
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37
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Franceschi G, Kraushofer F, Meier M, Parkinson GS, Schmid M, Diebold U, Riva M. A Model System for Photocatalysis: Ti-Doped α-Fe 2O 3(11̅02) Single-Crystalline Films. Chem Mater 2020; 32:3753-3764. [PMID: 32421058 PMCID: PMC7222102 DOI: 10.1021/acs.chemmater.9b04908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Hematite (α-Fe2O3) is one of the most investigated anode materials for photoelectrochemical water splitting. Its efficiency improves by doping with Ti, but the underlying mechanisms are not understood. One hurdle is separating the influence of doping on conductivity, surface states, and morphology, which all affect performance. To address this complexity, one needs well-defined model systems. We build such a model system by growing single-crystalline, atomically flat Ti-doped α-Fe2O3(11̅02) films by pulsed laser deposition (PLD). We characterize their surfaces, combining in situ scanning tunneling microscopy (STM) with density functional theory (DFT), and reveal how dilute Ti impurities modify the atomic-scale structure of the surface as a function of the oxygen chemical potential and Ti content. Ti preferentially substitutes subsurface Fe and causes a local restructuring of the topmost surface layers. Based on the experimental quantification of Ti-induced surface modifications and the structural model we have established, we propose a strategy that can be used to separate the effects of Ti-induced modifications to the surface atomic and electronic structures and bulk conductivity on the reactivity of Ti-doped hematite.
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Affiliation(s)
- Giada Franceschi
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
| | - Florian Kraushofer
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
| | - Matthias Meier
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
- Faculty
of Physics and Center for Computational Materials Science, University of Vienna, Sensengasse 8, 1090 Wien, Austria
| | - Gareth S. Parkinson
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
| | - Michael Schmid
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
| | - Ulrike Diebold
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
| | - Michele Riva
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040 Wien, Austria
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38
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Jakub Z, Hulva J, Ryan PTP, Duncan DA, Payne DJ, Bliem R, Ulreich M, Hofegger P, Kraushofer F, Meier M, Schmid M, Diebold U, Parkinson GS. Adsorbate-induced structural evolution changes the mechanism of CO oxidation on a Rh/Fe 3O 4(001) model catalyst. Nanoscale 2020; 12:5866-5875. [PMID: 32103229 DOI: 10.1039/c9nr10087c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The structure of a catalyst often changes in reactive environments, and following the structural evolution is crucial for the identification of the catalyst's active phase and reaction mechanism. Here we present an atomic-scale study of CO oxidation on a model Rh/Fe3O4(001) "single-atom" catalyst, which has a very different evolution depending on which of the two reactants, O2 or CO, is adsorbed first. Using temperature-programmed desorption (TPD) combined with scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), we show that O2 destabilizes Rh atoms, leading to the formation of RhxOy clusters; these catalyze CO oxidation via a Langmuir-Hinshelwood mechanism at temperatures as low as 200 K. If CO adsorbs first, the system is poisoned for direct interaction with O2, and CO oxidation is dominated by a Mars-van-Krevelen pathway at 480 K.
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Affiliation(s)
- Zdenek Jakub
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
| | - Jan Hulva
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
| | - Paul T P Ryan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK and Department of Materials, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - David A Duncan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - David J Payne
- Department of Materials, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Roland Bliem
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
| | - Manuel Ulreich
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
| | | | | | - Matthias Meier
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria. and University of Vienna, Faculty of Physics and Center for Computational Materials Science, 1090 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
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39
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Abstract
For most applications, zirconia (ZrO2) is doped with yttria. Doping leads to the stabilization of the tetragonal or cubic phase and increased oxygen ion conductivity. Most previous surface studies of yttria-doped zirconia were plagued by impurities, however. We have studied doping of pure, 5-monolayer ZrO2 films on Rh(111) by x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED). STM and LEED show that the tetragonal phase is stabilized by unexpectedly low dopant concentrations, 0.5 mol % Y2O3, even when the films are essentially fully oxidized (as evidenced by XPS core level shifts). XPS also shows Y segregation to the surface with an estimated segregation enthalpy of -23 ± 4 kJ/mol.
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Affiliation(s)
- Peter Lackner
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Amy J Brandt
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria
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40
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Kraushofer F, Mirabella F, Xu J, Pavelec J, Balajka J, Müllner M, Resch N, Jakub Z, Hulva J, Meier M, Schmid M, Diebold U, Parkinson GS. Self-limited growth of an oxyhydroxide phase at the Fe3O4(001) surface in liquid and ambient pressure water. J Chem Phys 2019; 151:154702. [DOI: 10.1063/1.5116652] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Florian Kraushofer
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Francesca Mirabella
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Jian Xu
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
- Department of Metallurgical Engineering, College of Materials Science and Engineering, Chongqing University, 174 Shazheng Street, Shapingba District, Chongqing 400044, China
| | - Jiří Pavelec
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Jan Balajka
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Matthias Müllner
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Nikolaus Resch
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Zdeněk Jakub
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Jan Hulva
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Matthias Meier
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Gareth S. Parkinson
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
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41
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Jakub Z, Hulva J, Meier M, Bliem R, Kraushofer F, Setvin M, Schmid M, Diebold U, Franchini C, Parkinson GS. Local Structure and Coordination Define Adsorption in a Model Ir 1 /Fe 3 O 4 Single-Atom Catalyst. Angew Chem Int Ed Engl 2019; 58:13961-13968. [PMID: 31339617 PMCID: PMC6790613 DOI: 10.1002/anie.201907536] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/18/2019] [Indexed: 11/24/2022]
Abstract
Single-atom catalysts (SACs) bridge homo- and heterogeneous catalysis because the active site is a metal atom coordinated to surface ligands. The local binding environment of the atom should thus strongly influence how reactants adsorb. Now, atomically resolved scanning-probe microscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption, and DFT are used to study how CO binds at different Ir1 sites on a precisely defined Fe3 O4 (001) support. The two- and five-fold-coordinated Ir adatoms bind CO more strongly than metallic Ir, and adopt structures consistent with square-planar IrI and octahedral IrIII complexes, respectively. Ir incorporates into the subsurface already at 450 K, becoming inactive for adsorption. Above 900 K, the Ir adatoms agglomerate to form nanoparticles encapsulated by iron oxide. These results demonstrate the link between SAC systems and coordination complexes, and that incorporation into the support is an important deactivation mechanism.
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Affiliation(s)
- Zdenek Jakub
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Jan Hulva
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Matthias Meier
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
- Center for Computational Materials ScienceFaculty of PhysicsUniversity of Vienna1090ViennaAustria
| | - Roland Bliem
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
- Current Address: Advanced Research Center for Nanolithography (ARCNL)1090 BAAmsterdamThe Netherlands
| | - Florian Kraushofer
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Martin Setvin
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Michael Schmid
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Ulrike Diebold
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
| | - Cesare Franchini
- Center for Computational Materials ScienceFaculty of PhysicsUniversity of Vienna1090ViennaAustria
| | - Gareth S. Parkinson
- Institute of Applied PhysicsTU WienWiedner Hauptstr. 8–10/1341040ViennaAustria
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42
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Jakub Z, Hulva J, Meier M, Bliem R, Kraushofer F, Setvin M, Schmid M, Diebold U, Franchini C, Parkinson GS. Local Structure and Coordination Define Adsorption in a Model Ir
1
/Fe
3
O
4
Single‐Atom Catalyst. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907536] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zdenek Jakub
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Jan Hulva
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Matthias Meier
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
- Center for Computational Materials ScienceFaculty of PhysicsUniversity of Vienna 1090 Vienna Austria
| | - Roland Bliem
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
- Current Address: Advanced Research Center for Nanolithography (ARCNL) 1090 BA Amsterdam The Netherlands
| | - Florian Kraushofer
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Martin Setvin
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Michael Schmid
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Ulrike Diebold
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
| | - Cesare Franchini
- Center for Computational Materials ScienceFaculty of PhysicsUniversity of Vienna 1090 Vienna Austria
| | - Gareth S. Parkinson
- Institute of Applied PhysicsTU Wien Wiedner Hauptstr. 8–10/134 1040 Vienna Austria
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43
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Riva M, Franceschi G, Schmid M, Diebold U. The surface phase diagram of La 0.8Sr 0.2MnO 3 in STM. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s205327331909226x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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44
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Lackner P, Zou Z, Mayr S, Diebold U, Schmid M. Using photoelectron spectroscopy to observe oxygen spillover to zirconia. Phys Chem Chem Phys 2019; 21:17613-17620. [PMID: 31386706 DOI: 10.1039/c9cp03322j] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
X-ray photoelectron spectroscopy (XPS) of five-monolayer-thick ZrO2 films reveals a core level binding energy difference of up to 1.8 eV between the tetragonal and monoclinic phase. This difference is explained by positively charged oxygen vacancies in the tetragonal films, which are slightly reduced. Due to the large band gap of zirconia (≈5-6 eV), these charges shift the electron levels, leading to higher binding energies of reduced tetragonal films w.r.t. fully oxidized monoclinic films. These core level shifts have the opposite direction than what is usually encountered for reduced transition metal oxides. The vacancies can be filled via oxygen spillover from a catalyst that enables O2 dissociation. This can be either a metal deposited on the film, or, if the film has holes, the metallic (in our case, Rh) substrate. Our study also confirms that tetragonal ZrO2 is stabilized via oxygen vacancies and shows that the XPS binding energy difference between O 1s and Zr 3d solely depends on the crystallographic phase.
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Affiliation(s)
- Peter Lackner
- Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
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45
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Reticcioli M, Sokolović I, Schmid M, Diebold U, Setvin M, Franchini C. Interplay between Adsorbates and Polarons: CO on Rutile TiO_{2}(110). Phys Rev Lett 2019; 122:016805. [PMID: 31012645 DOI: 10.1103/physrevlett.122.016805] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Polaron formation plays a major role in determining the structural, electrical, and chemical properties of ionic crystals. Using a combination of first-principles calculations, scanning tunneling microscopy, and atomic force microscopy, we analyze the interaction of polarons with CO molecules adsorbed on the reduced rutile TiO_{2}(110) surface. Adsorbed CO shows attractive coupling with polarons in the surface layer, and repulsive interaction with polarons in the subsurface layer. As a result, CO adsorption depends on the reduction state of the sample. For slightly reduced surfaces, many adsorption configurations with comparable adsorption energies exist and polarons reside in the subsurface layer. At strongly reduced surfaces, two adsorption configurations dominate: either inside an oxygen vacancy, or at surface Ti_{5c} sites, coupled with a surface polaron. Similar conclusions are predicted for TiO_{2}(110) surfaces containing near-surface Ti interstitials. These results show that polarons are of primary importance for understanding the performance of polar semiconductors and transition metal oxides in catalysis and energy-related applications.
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Affiliation(s)
- Michele Reticcioli
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna 1090, Austria
| | - Igor Sokolović
- Institute of Applied Physics, Technische Universität Wien, Vienna 1090, Austria
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, Vienna 1090, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, Vienna 1090, Austria
| | - Martin Setvin
- Institute of Applied Physics, Technische Universität Wien, Vienna 1090, Austria
| | - Cesare Franchini
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, Vienna 1090, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
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46
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Balajka J, Hines MA, DeBenedetti WJI, Komora M, Pavelec J, Schmid M, Diebold U. High-affinity adsorption leads to molecularly ordered interfaces on TiO 2 in air and solution. Science 2018; 361:786-789. [PMID: 30139869 DOI: 10.1126/science.aat6752] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 06/25/2018] [Indexed: 02/05/2023]
Abstract
Researchers around the world have observed the formation of molecularly ordered structures of unknown origin on the surface of titanium dioxide (TiO2) photocatalysts exposed to air and solution. Using a combination of atomic-scale microscopy and spectroscopy, we show that TiO2 selectively adsorbs atmospheric carboxylic acids that are typically present in parts-per-billion concentrations while effectively repelling other adsorbates, such as alcohols, that are present in much higher concentrations. The high affinity of the surface for carboxylic acids is attributed to their bidentate binding. These self-assembled monolayers have the unusual property of being both hydrophobic and highly water-soluble, which may contribute to the self-cleaning properties of TiO2 This finding is relevant to TiO2 photocatalysis, because the self-assembled carboxylate monolayers block the undercoordinated surface cation sites typically implicated in photocatalysis.
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Affiliation(s)
- Jan Balajka
- Institute of Applied Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Melissa A Hines
- Department of Chemistry, Cornell University, Ithaca, NY 14853, USA
| | | | - Mojmir Komora
- Institute of Applied Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria.,Central European Institute of Technology, Purkyňova 123, Brno 612 00, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2896/2, Brno 616 69, Czech Republic
| | - Jiri Pavelec
- Institute of Applied Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria.
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47
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Riva M, Kubicek M, Hao X, Franceschi G, Gerhold S, Schmid M, Hutter H, Fleig J, Franchini C, Yildiz B, Diebold U. Influence of surface atomic structure demonstrated on oxygen incorporation mechanism at a model perovskite oxide. Nat Commun 2018; 9:3710. [PMID: 30213926 PMCID: PMC6137039 DOI: 10.1038/s41467-018-05685-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/22/2018] [Indexed: 11/08/2022] Open
Abstract
Perovskite oxide surfaces catalyze oxygen exchange reactions that are crucial for fuel cells, electrolyzers, and thermochemical fuel synthesis. Here, by bridging the gap between surface analysis with atomic resolution and oxygen exchange kinetics measurements, we demonstrate how the exact surface atomic structure can determine the reactivity for oxygen exchange reactions on a model perovskite oxide. Two precisely controlled surface reconstructions with (4 × 1) and (2 × 5) symmetry on 0.5 wt.% Nb-doped SrTiO3(110) were subjected to isotopically labeled oxygen exchange at 450 °C. The oxygen incorporation rate is three times higher on the (4 × 1) surface phase compared to the (2 × 5). Common models of surface reactivity based on the availability of oxygen vacancies or on the ease of electron transfer cannot account for this difference. We propose a structure-driven oxygen exchange mechanism, relying on the flexibility of the surface coordination polyhedra that transform upon dissociation of oxygen molecules.
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Affiliation(s)
- Michele Riva
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria
| | - Markus Kubicek
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164EC, 1060, Wien, Austria
| | - Xianfeng Hao
- Key Laboratory of Applied Chemistry, Department of Chemical Engineering, Yanshan University, 066004, Qinhuangdao, China
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, Sensengasse 8/8, 1090, Vienna, Austria
| | - Giada Franceschi
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria
| | - Stefan Gerhold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria
| | - Herbert Hutter
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164EC, 1060, Wien, Austria
| | - Juergen Fleig
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164EC, 1060, Wien, Austria
| | - Cesare Franchini
- Faculty of Physics and Center for Computational Materials Science, University of Vienna, Sensengasse 8/8, 1090, Vienna, Austria
| | - Bilge Yildiz
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria.
- Laboratory for Electrochemical Interfaces, Departments of Nuclear Science and Engineering, and Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraβe 8-10/E134, 1040, Wien, Austria.
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48
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Balajka J, Pavelec J, Komora M, Schmid M, Diebold U. Apparatus for dosing liquid water in ultrahigh vacuum. Rev Sci Instrum 2018; 89:083906. [PMID: 30184714 DOI: 10.1063/1.5046846] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/11/2018] [Indexed: 06/08/2023]
Abstract
The structure of the solid-liquid interface often defines the function and performance of materials in applications. To study this interface at the atomic scale, we extended an ultrahigh vacuum (UHV) surface-science chamber with an apparatus that allows bringing a surface in contact with ultrapure liquid water without exposure to air. In this process, a sample, typically a single crystal prepared and characterized in UHV, is transferred into a separate, small chamber. This chamber already contains a volume of ultrapure water ice. The ice is at cryogenic temperature, which reduces its vapor pressure to the UHV range. Upon warming, the ice melts and forms a liquid droplet, which is deposited on the sample. In test experiments, a rutile TiO2(110) single crystal exposed to liquid water showed unprecedented surface purity, as established by X-ray photoelectron spectroscopy and scanning tunneling microscopy. These results enabled us to separate the effect of pure water from the effect of low-level impurities present in the air. Other possible uses of the setup are discussed.
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Affiliation(s)
- Jan Balajka
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Jiri Pavelec
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Mojmir Komora
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
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49
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Meier M, Hulva J, Jakub Z, Pavelec J, Setvin M, Bliem R, Schmid M, Diebold U, Franchini C, Parkinson GS. Water agglomerates on Fe 3O 4(001). Proc Natl Acad Sci U S A 2018; 115:E5642-E5650. [PMID: 29866854 PMCID: PMC6016784 DOI: 10.1073/pnas.1801661115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Determining the structure of water adsorbed on solid surfaces is a notoriously difficult task and pushes the limits of experimental and theoretical techniques. Here, we follow the evolution of water agglomerates on Fe3O4(001); a complex mineral surface relevant in both modern technology and the natural environment. Strong OH-H2O bonds drive the formation of partially dissociated water dimers at low coverage, but a surface reconstruction restricts the density of such species to one per unit cell. The dimers act as an anchor for further water molecules as the coverage increases, leading first to partially dissociated water trimers, and then to a ring-like, hydrogen-bonded network that covers the entire surface. Unraveling this complexity requires the concerted application of several state-of-the-art methods. Quantitative temperature-programmed desorption (TPD) reveals the coverage of stable structures, monochromatic X-ray photoelectron spectroscopy (XPS) shows the extent of partial dissociation, and noncontact atomic force microscopy (AFM) using a CO-functionalized tip provides a direct view of the agglomerate structure. Together, these data provide a stringent test of the minimum-energy configurations determined via a van der Waals density functional theory (DFT)-based genetic search.
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Affiliation(s)
- Matthias Meier
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
- Center for Computational Materials Science, Faculty of Physics, University of Vienna, 1090 Vienna, Austria
| | - Jan Hulva
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Zdeněk Jakub
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Jiří Pavelec
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Martin Setvin
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Roland Bliem
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Michael Schmid
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria
| | - Cesare Franchini
- Center for Computational Materials Science, Faculty of Physics, University of Vienna, 1090 Vienna, Austria
| | - Gareth S Parkinson
- Institute of Applied Physics, Technische Universität Wien, 1040 Vienna, Austria;
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Wagner M, Hofinger J, Setvín M, Boatner LA, Schmid M, Diebold U. Prototypical Organic-Oxide Interface: Intramolecular Resolution of Sexiphenyl on In 2O 3(111). ACS Appl Mater Interfaces 2018; 10:14175-14182. [PMID: 29589447 PMCID: PMC5940326 DOI: 10.1021/acsami.8b02177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/28/2018] [Indexed: 05/19/2023]
Abstract
The performance of an organic semiconductor device is critically determined by the geometric alignment, orientation, and ordering of the organic molecules. Although an organic multilayer eventually adopts the crystal structure of the organic material, the alignment and configuration at the interface with the substrate/electrode material are essential for charge injection into the organic layer. This work focuses on the prototypical organic semiconductor para-sexiphenyl (6P) adsorbed on In2O3(111), the thermodynamically most stable surface of the material that the most common transparent conducting oxide, indium tin oxide, is based on. The onset of nucleation and formation of the first monolayer are followed with atomically resolved scanning tunneling microscopy and noncontact atomic force microscopy (nc-AFM). Annealing to 200 °C provides sufficient thermal energy for the molecules to orient themselves along the high-symmetry directions of the surface, leading to a single adsorption site. The AFM data suggests an essentially planar adsorption geometry. With increasing coverage, the 6P molecules first form a loose network with a poor long-range order. Eventually, the molecules reorient into an ordered monolayer. This first monolayer has a densely packed, well-ordered (2 × 1) structure with one 6P per In2O3(111) substrate unit cell, that is, a molecular density of 5.64 × 1013 cm-2.
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Affiliation(s)
- Margareta Wagner
- Institute of Applied
Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Jakob Hofinger
- Institute of Applied
Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Martin Setvín
- Institute of Applied
Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Lynn A. Boatner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael Schmid
- Institute of Applied
Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Ulrike Diebold
- Institute of Applied
Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
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