1
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Liu D, Li L, Jiang N. Nanoscale Chemical Probing of Metal-Supported Ultrathin Ferrous Oxide via Tip-Enhanced Raman Spectroscopy and Scanning Tunneling Microscopy. CHEMICAL & BIOMEDICAL IMAGING 2024; 2:345-351. [PMID: 38817320 PMCID: PMC11134605 DOI: 10.1021/cbmi.4c00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/04/2024] [Accepted: 03/11/2024] [Indexed: 06/01/2024]
Abstract
Metal-supported ultrathin ferrous oxide (FeO) has attracted immense interest in academia and industry due to its widespread applications in heterogeneous catalysis. However, chemical insight into the local structural characteristics of FeO, despite its critical importance in elucidating structure-property relationships, remains elusive. In this work, we report the nanoscale chemical probing of gold (Au)-supported ultrathin FeO via ultrahigh-vacuum tip-enhanced Raman spectroscopy (UHV-TERS) and scanning tunneling microscopy (STM). For comparative analysis, single-crystal Au(111) and Au(100) substrates are used to tune the interfacial properties of FeO. Although STM images show distinctly different moiré superstructures on FeO nanoislands on Au(111) and Au(100), TERS demonstrates the same chemical nature of FeO by comparable vibrational features. In addition, combined TERS and STM measurements identify a unique wrinkled FeO structure on Au(100), which is correlated to the reassembly of the intrinsic Au(100) surface reconstruction due to FeO deposition. Beyond revealing the morphologies of ultrathin FeO on Au substrates, our study provides a thorough understanding of the local interfacial properties and interactions of FeO on Au, which could shed light on the rational design of metal-supported FeO catalysts. Furthermore, this work demonstrates the promising utility of combined TERS and STM in chemically probing the structural properties of metal-supported ultrathin oxides on the nanoscale.
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Affiliation(s)
- Dairong Liu
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
| | - Linfei Li
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
| | - Nan Jiang
- Department
of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, United States
- Department
of Physics, University of Illinois Chicago, Chicago, Illinois 60607, United States
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2
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Rattigan E, Sun Z, Gallo T, Nino MA, Parreiras SDO, Martín-Fuentes C, Martin-Romano JC, Écija D, Escudero C, Villar I, Rodríguez-Fernández J, Lauritsen JV. The cobalt oxidation state in preferential CO oxidation on CoO x/Pt(111) investigated by operando X-ray photoemission spectroscopy. Phys Chem Chem Phys 2022; 24:9236-9246. [PMID: 35388844 DOI: 10.1039/d2cp00399f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The combination of a reducible transition metal oxide and a noble metal such as Pt often leads to active low-temperature catalysts for the preferential oxidation of CO in excess H2 gas (PROX reaction). While CO oxidation has been investigated for such systems in model studies, the added influence of hydrogen gas, representative of PROX, remains less explored. Herein, we use ambient pressure scanning tunneling microscopy and ambient pressure X-ray photoelectron spectroscopy on a CoOx/Pt(111) planar model catalyst to analyze the active phase and the adsorbed species at the CoOx/Pt(111) interface under atmospheres of CO and O2 with a varying partial pressure of H2 gas. By following the evolution of the Co oxidation state as the catalyst is brought to a reaction temperature of above 150 °C, we determine that the active state is characterized by the transformation from planar CoO with Co in the 2+ state to a mixed Co2+/Co3+ phase at the temperature where CO2 production is first observed. Furthermore, our spectroscopy observations of the surface species suggest a reaction pathway for CO oxidation, proceeding from CO exclusively adsorbed on Co2+ sites reacting with the lattice O from the oxide. Under steady state CO oxidation conditions (CO/O2), the mixed oxide phase is replenished from oxygen incorporating into cobalt oxide nanoislands. In CO/O2/H2, however, the onset of the active Co2+/Co3+ phase formation is surprisingly sensitive to the H2 pressure, which we explain by the formation of several possible hydroxylated intermediate phases that expose both Co2+ and Co3+. This variation, however, has no influence on the temperature where CO oxidation is observed. Our study points to the general importance of a dynamic reducibility window of cobalt oxide, which is influenced by hydroxylation, and the bonding strength of CO to the reduced oxide phase as important parameters for the activity of the system.
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Affiliation(s)
- Eoghan Rattigan
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
| | - Zhaozong Sun
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
| | - Tamires Gallo
- Synchrotron Radiation Research, Lund University, Sölvegatan 14, 223 62 Lund, Sweden
| | - Miguel Angel Nino
- IMDEA Nanoscience Institute, Ciudad Universitaria de Cantoblanco, Calle Faraday 9, 28049, Madrid, Spain.,ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | | | - Cristina Martín-Fuentes
- IMDEA Nanoscience Institute, Ciudad Universitaria de Cantoblanco, Calle Faraday 9, 28049, Madrid, Spain
| | - Juan Carlos Martin-Romano
- IMDEA Nanoscience Institute, Ciudad Universitaria de Cantoblanco, Calle Faraday 9, 28049, Madrid, Spain
| | - David Écija
- IMDEA Nanoscience Institute, Ciudad Universitaria de Cantoblanco, Calle Faraday 9, 28049, Madrid, Spain
| | - Carlos Escudero
- ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | - Ignacio Villar
- ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | | | - Jeppe V Lauritsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
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3
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Gajdek D, Olsson PAT, Blomberg S, Gustafson J, Carlsson PA, Haase D, Lundgren E, Merte LR. Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O 2 Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:3411-3418. [PMID: 35242268 PMCID: PMC8883796 DOI: 10.1021/acs.jpcc.1c10284] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/03/2022] [Indexed: 06/14/2023]
Abstract
We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O2, with the aim of identifying the Co phases present and their transformations under oxidizing and reducing conditions. X-ray absorption near edge structure (XANES) spectra show clear changes in the chemical state of Co, with the 2+ state predominant under CO exposure and the 3+ state predominant under O2-rich conditions. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis shows that the CoO bilayer characterized in ultrahigh vacuum is not formed under the conditions used in this study. Instead, the spectra acquired at low temperatures suggest formation of cobalt hydroxide and oxyhydroxide. At higher temperatures, the spectra indicate dewetting of the film and suggest formation of bulklike Co3O4 under oxidizing conditions. The experiments demonstrate the power of hard X-ray spectroscopy to probe the structures of well-defined oxide monolayers on metal single crystals under realistic catalytic conditions.
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Affiliation(s)
- Dorotea Gajdek
- Department
of Materials Science and Applied Mathematics, Malmö University, SE-211 19 Malmö, Sweden
- NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Pär A. T. Olsson
- Department
of Materials Science and Applied Mathematics, Malmö University, SE-211 19 Malmö, Sweden
- Division
of Mechanics, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Sara Blomberg
- NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- Department
of Chemical Engineering, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Johan Gustafson
- Division
of Synchrotron Radiation Research, Lund
University, Box 118, SE-221
00 Lund, Sweden
| | - Per-Anders Carlsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-412 96 Göteborg, Sweden
- Competence
Centre for Catalysis, Chalmers University
of Technology, SE-412 96 Göteborg, Sweden
| | - Dörthe Haase
- MAX
IV Laboratory, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Edvin Lundgren
- NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- Division
of Synchrotron Radiation Research, Lund
University, Box 118, SE-221
00 Lund, Sweden
| | - Lindsay R. Merte
- Department
of Materials Science and Applied Mathematics, Malmö University, SE-211 19 Malmö, Sweden
- NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
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4
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Kadam SA, Phan GT, Pham DV, Patil RA, Lai CC, Chen YR, Liou Y, Ma YR. Doping-free bandgap tunability in Fe 2O 3 nanostructured films. NANOSCALE ADVANCES 2021; 3:5581-5588. [PMID: 36133276 PMCID: PMC9418971 DOI: 10.1039/d1na00442e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/29/2021] [Indexed: 06/16/2023]
Abstract
A tunable bandgap without doping is highly desirable for applications in optoelectronic devices. Herein, we develop a new method which can tune the bandgap without any doping. In the present research, the bandgap of Fe2O3 nanostructured films is simply tuned by changing the synthesis temperature. The Fe2O3 nanostructured films are synthesized on ITO/glass substrates at temperatures of 1100, 1150, 1200, and 1250 °C using the hot filament metal oxide vapor deposition (HFMOVD) and thermal oxidation techniques. The Fe2O3 nanostructured films contain two mixtures of Fe2+ and Fe3+ cations and two trigonal (α) and cubic (γ) phases. The increase of the Fe2+ cations and cubic (γ) phase with the elevated synthesis temperatures lifted the valence band edge, indicating a reduction in the bandgap. The linear bandgap reduction of 0.55 eV without any doping makes the Fe2O3 nanostructured films promising materials for applications in bandgap engineering, optoelectronic devices, and energy storage devices.
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Affiliation(s)
- Sujit A Kadam
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
| | - Giang Thi Phan
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
| | - Duy Van Pham
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
- Center for Condensed Matter Sciences, National Taiwan University Taipei 10617 Taiwan
| | - Ranjit A Patil
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
| | - Chien-Chih Lai
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
| | - Yan-Ruei Chen
- Institute of Physics, Academia Sinica Taipei 11529 Taiwan
| | - Yung Liou
- Institute of Physics, Academia Sinica Taipei 11529 Taiwan
| | - Yuan-Ron Ma
- Department of Physics, National Dong Hwa University Hualien 97401 Taiwan
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5
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Zhao S, Lin L, Huang W, Zhang R, Wang D, Mu R, Fu Q, Bao X. Design of Lewis Pairs via Interface Engineering of Oxide-Metal Composite Catalyst for Water Activation. J Phys Chem Lett 2021; 12:1443-1452. [PMID: 33523659 DOI: 10.1021/acs.jpclett.0c03760] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The rational design and controlled construction of active centers remain grand challenges in heterogeneous catalysis, in particular for oxide catalysts with complex surface and interface structures. This work describes a facile way in the design of highly active Ni-O Lewis pairs for water activation where Ni and O sites act as Lewis acid and base, respectively. Surface science experiments indicate that dissociative adsorption of water occurs at edges of NiOx nanoislands grown on Au(111) and NiOx-Ni interfaces formed by further depositing metallic Ni layers along the edges of NiOx nanoislands. Enhanced activity of Ni-O Lewis pairs at the NiOx-Ni interface has been demonstrated by theoretical calculations, which are attributed to the higher Lewis acidity of metallic Ni sites and synergy of the metal and oxide components. Moreover, proton can migrate away from the NiOx-Ni interface and refresh the O base sites, leading to further hydroxylation of the neighboring Ni acid sites.
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Affiliation(s)
- Siqin Zhao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Le Lin
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wugen Huang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rankun Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Dongqing Wang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rentao Mu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qiang Fu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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6
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Abstract
Abstract
Scanning tunneling microscopy (STM) has gained increasing attention in the field of electrocatalysis due to its ability to reveal electrocatalyst surface structures down to the atomic level in either ultra-high-vacuum (UHV) or harsh electrochemical conditions. The detailed knowledge of surface structures, surface electronic structures, surface active sites as well as the interaction between surface adsorbates and electrocatalysts is highly beneficial in the study of electrocatalytic mechanisms and for the rational design of electrocatalysts. Based on this, this review will discuss the application of STM in the characterization of electrocatalyst surfaces and the investigation of electrochemical interfaces between electrocatalyst surfaces and reactants. Based on different operating conditions, UHV-STM and STM in electrochemical environments (EC-STM) are discussed separately. This review will also present emerging techniques including high-speed EC-STM, scanning noise microscopy and tip-enhanced Raman spectroscopy.
Graphic Abstract
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7
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Jiang Y, Zhu Y, Zhou D, Jiang Z, Si N, Stacchiola D, Niu T. Reversible oxidation and reduction of gold-supported iron oxide islands at room temperature. J Chem Phys 2020; 152:074710. [PMID: 32087652 DOI: 10.1063/1.5136279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Monolayer iron oxides grown on metal substrates have widely been used as model systems in heterogeneous catalysis. By means of ambient-pressure scanning tunneling microscopy (AP-STM), we studied the in situ oxidation and reduction of FeO(111) grown on Au(111) by oxygen (O2) and carbon monoxide (CO), respectively. Oxygen dislocation lines present on FeO islands are highly active for O2 dissociation. X-ray photoelectron spectroscopy measurements distinctly reveal the reversible oxidation and reduction of FeO islands after sequential exposure to O2 and CO. Our AP-STM results show that excess O atoms can be further incorporated on dislocation lines and react with CO, whereas the CO is not strong enough to reduce the FeO supported on Au(111) that is essential to retain the activity of oxygen dislocation lines.
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Affiliation(s)
- Yixuan Jiang
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, No. 200, Xiaolingwei 210094, China
| | - Yaguang Zhu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973-5000, USA
| | - Dechun Zhou
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, No. 200, Xiaolingwei 210094, China
| | - Zhao Jiang
- Department of Chemical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Nan Si
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, No. 200, Xiaolingwei 210094, China
| | - Dario Stacchiola
- Center for Functional Nanomaterials, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973-5000, USA
| | - Tianchao Niu
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, No. 200, Xiaolingwei 210094, China
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8
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Zhou Z, Liu P, Yang F, Bao X. Interface-confined triangular FeO x nanoclusters on Pt(111). J Chem Phys 2019; 151:214704. [PMID: 31822092 DOI: 10.1063/1.5129266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Under the oxidizing condition, the cheap metal component of bimetallic catalysts often segregates to the surface and forms oxide nanoclusters (NCs) supported on the metal surface, which exhibit unique structures and catalytic properties drastically different from the corresponding bulk materials. Here, density functional theory calculations are employed to describe the atomic and electronic structures of a series of triangular FeOx NCs confined on Pt(111) with the size ranging from ∼0.3 nm to ∼2.2 nm, which behave differently from the FeO film reported previously. The lattice of supported FeOx NCs on Pt(111) is found to vary not only with the NC size but also with the Fe/O ratio or the edge termination. Owing to a strong FeOx-Pt interaction, the heterogeneous distribution of local atomic and electronic structures of Fe across the FeOx NC is observed, though most of Fe atoms are positioned at the threefold hollow site of Pt(111). Our study not only sheds light on the catalytically active sites of supported FeOx NCs but also provides guidance for the design of highly active and stable oxide nanocatalysts under reactive environment.
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Affiliation(s)
- Zhiwen Zhou
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Ping Liu
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Fan Yang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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9
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Li Y, Adamsen KC, Lammich L, Lauritsen JV, Wendt S. Atomic-Scale View of the Oxidation and Reduction of Supported Ultrathin FeO Islands. ACS NANO 2019; 13:11632-11641. [PMID: 31513376 DOI: 10.1021/acsnano.9b05470] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
By means of scanning tunneling microscopy (STM) measurements, we studied in situ the oxidation and reduction of FeO bilayer islands on Au(111) by oxygen (O2) and hydrogen (H2), respectively. The FeO islands respond very dynamically toward O2, with the coordinatively unsaturated ferrous (CUF) sites at the island edges being essential for O2 dissociation and O atom incorporation. An STM movie obtained during oxidation reveals how further O2 molecules can dissociate after the consumption of all initially existing CUF sites through the formation of new CUF sites. In contrast, we found that H2 molecules only dissociate when vibrationally excited through the ion gauge and only at the basal plane of FeO islands, implying that the CUF sites are not relevant for H2 dissociation. Our STM results reveal how excess O atoms are incorporated and released in O2 and H2 and thus shed light onto the stability of inverse catalysts during a catalyzed reaction.
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Affiliation(s)
- Yijia Li
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy , Aarhus University , DK-8000 Aarhus C , Denmark
| | - Kræn C Adamsen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy , Aarhus University , DK-8000 Aarhus C , Denmark
| | - Lutz Lammich
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy , Aarhus University , DK-8000 Aarhus C , Denmark
| | - Jeppe V Lauritsen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy , Aarhus University , DK-8000 Aarhus C , Denmark
| | - Stefan Wendt
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy , Aarhus University , DK-8000 Aarhus C , Denmark
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10
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Barcaro G, Fortunelli A. 2D oxides on metal materials: concepts, status, and perspectives. Phys Chem Chem Phys 2019; 21:11510-11536. [DOI: 10.1039/c9cp00972h] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional oxide-on-metal materials: concepts, methods, and link to technological applications, with 5 subtopics: structural motifs, robustness, catalysis, ternaries, and nanopatterning.
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11
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Michalak N, Miłosz Z, Peschel G, Prieto M, Xiong F, Wojciechowski P, Schmidt T, Lewandowski M. Symmetry-Induced Structuring of Ultrathin FeO and Fe₃O₄ Films on Pt(111) and Ru(0001). NANOMATERIALS 2018; 8:nano8090719. [PMID: 30213086 PMCID: PMC6164621 DOI: 10.3390/nano8090719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 01/01/2023]
Abstract
Iron oxide films epitaxially grown on close-packed metal single crystal substrates exhibit nearly-perfect structural order, high catalytic activity (FeO) and room-temperature magnetism (Fe3O4). However, the morphology of the films, especially in the ultrathin regime, can be significantly influenced by the crystalline structure of the used support. This work reports an ultra-high vacuum (UHV) low energy electron/synchrotron light-based X-ray photoemission electron microscopy (LEEM/XPEEM) and electron diffraction (µLEED) study of the growth of FeO and Fe3O4 on two closed-packed metal single crystal surfaces: Pt(111) and Ru(0001). The results reveal the influence of the mutual orientation of adjacent substrate terraces on the morphology of iron oxide films epitaxially grown on top of them. On fcc Pt(111), which has the same mutual orientation of adjacent monoatomic terraces, FeO(111) grows with the same in-plane orientation on all substrate terraces. For Fe3O4(111), one or two orientations are observed depending on the growth conditions. On hcp Ru(0001), the adjacent terraces of which are ‘rotated’ by 180° with respect to each other, the in-plane orientation of initial FeO(111) and Fe3O4(111) crystallites is determined by the orientation of the substrate terrace on which they nucleated. The adaptation of three-fold symmetric iron oxides to three-fold symmetric substrate terraces leads to natural structuring of iron oxide films, i.e., the formation of patch-like magnetite layers on Pt(111) and stripe-like FeO and Fe3O4 structures on Ru(0001).
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Affiliation(s)
- Natalia Michalak
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - Zygmunt Miłosz
- NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
| | - Gina Peschel
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Mauricio Prieto
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Feng Xiong
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
- Department of Chemical Physics, University of Science and Technology of China, No. 96, JinZhai Road Baohe District, Hefei 230026, China.
| | - Paweł Wojciechowski
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - Thomas Schmidt
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Mikołaj Lewandowski
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
- NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
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12
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Zhang K, Li L, Shaikhutdinov S, Freund HJ. Carbon Monoxide Oxidation on Metal-Supported Monolayer Oxide Films: Establishing Which Interface is Active. Angew Chem Int Ed Engl 2018; 57:1261-1265. [DOI: 10.1002/anie.201710934] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/22/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Ke Zhang
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
- Present address: Institute of Physics; Ecole Polytechnique Federale de Lausanne (EPFL); 1015 Lausanne Switzerland
| | - Linfei Li
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
| | | | - Hans-Joachim Freund
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
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13
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Zhang K, Li L, Shaikhutdinov S, Freund HJ. Carbon Monoxide Oxidation on Metal-Supported Monolayer Oxide Films: Establishing Which Interface is Active. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201710934] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Ke Zhang
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
- Present address: Institute of Physics; Ecole Polytechnique Federale de Lausanne (EPFL); 1015 Lausanne Switzerland
| | - Linfei Li
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
| | | | - Hans-Joachim Freund
- Fritz-Haber-Institute, Max Planck Society; Faradayweg 4-6 14195 Berlin Germany
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14
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Fester J, Sun Z, Rodríguez-Fernández J, Walton A, Lauritsen JV. Phase Transitions of Cobalt Oxide Bilayers on Au(111) and Pt(111): The Role of Edge Sites and Substrate Interactions. J Phys Chem B 2017; 122:561-571. [DOI: 10.1021/acs.jpcb.7b04944] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jakob Fester
- Interdisciplinary Nanoscience
Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Zhaozong Sun
- Interdisciplinary Nanoscience
Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | | | - Alex Walton
- Interdisciplinary Nanoscience
Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Jeppe V. Lauritsen
- Interdisciplinary Nanoscience
Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
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15
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Chen Z, Mao Y, Chen J, Wang H, Li Y, Hu P. Understanding the Dual Active Sites of the FeO/Pt(111) Interface and Reaction Kinetics: Density Functional Theory Study on Methanol Oxidation to Formaldehyde. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00541] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zongjia Chen
- Key
Laboratory for Advanced Materials, Center for Computational Chemistry
and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- School
of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, U.K
| | - Yu Mao
- School
of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, U.K
| | - Jianfu Chen
- Key
Laboratory for Advanced Materials, Center for Computational Chemistry
and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Haifeng Wang
- Key
Laboratory for Advanced Materials, Center for Computational Chemistry
and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Yadong Li
- Department
of Chemistry, Tsinghua University, Beijing 100084, People’s Republic of China
| | - P. Hu
- Key
Laboratory for Advanced Materials, Center for Computational Chemistry
and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- School
of Chemistry and Chemical Engineering, The Queen’s University of Belfast, Belfast BT9 5AG, U.K
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16
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Fester J, Bajdich M, Walton AS, Sun Z, Plessow PN, Vojvodic A, Lauritsen JV. Comparative Analysis of Cobalt Oxide Nanoisland Stability and Edge Structures on Three Related Noble Metal Surfaces: Au(111), Pt(111) and Ag(111). Top Catal 2016. [DOI: 10.1007/s11244-016-0708-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Shipilin M, Lundgren E, Gustafson J, Zhang C, Bertram F, Nicklin C, Heard CJ, Grönbeck H, Zhang F, Choi J, Mehar V, Weaver JF, Merte LR. Fe Oxides on Ag Surfaces: Structure and Reactivity. Top Catal 2016. [DOI: 10.1007/s11244-016-0714-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
One layer thick iron oxide films are attractive from both applied and fundamental science perspectives. The structural and chemical properties of these systems can be tuned by changing the substrate, making them promising materials for heterogeneous catalysis. In the present work, we investigate the structure of FeO(111) monolayer films grown on Ag(100) and Ag(111) substrates by means of microscopy and diffraction techniques and compare it with the structure of FeO(111) grown on other substrates reported in literature. We also study the NO adsorption properties of FeO(111)/Ag(100) and FeO(111)/Ag(111) systems utilizing different spectroscopic techniques. We discuss similarities and differences in the data obtained from adsorption experiments and compare it with previous results for FeO(111)/Pt(111).
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18
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Greeley J. Theoretical Heterogeneous Catalysis: Scaling Relationships and Computational Catalyst Design. Annu Rev Chem Biomol Eng 2016; 7:605-35. [PMID: 27088666 DOI: 10.1146/annurev-chembioeng-080615-034413] [Citation(s) in RCA: 197] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Scaling relationships are theoretical constructs that relate the binding energies of a wide variety of catalytic intermediates across a range of catalyst surfaces. Such relationships are ultimately derived from bond order conservation principles that were first introduced several decades ago. Through the growing power of computational surface science and catalysis, these concepts and their applications have recently begun to have a major impact in studies of catalytic reactivity and heterogeneous catalyst design. In this review, the detailed theory behind scaling relationships is discussed, and the existence of these relationships for catalytic materials ranging from pure metal to oxide surfaces, for numerous classes of molecules, and for a variety of catalytic surface structures is described. The use of the relationships to understand and elucidate reactivity trends across wide classes of catalytic surfaces and, in some cases, to predict optimal catalysts for certain chemical reactions, is explored. Finally, the observation that, in spite of the tremendous power of scaling relationships, their very existence places limits on the maximum rates that may be obtained for the catalyst classes in question is discussed, and promising strategies are explored to overcome these limitations to usher in a new era of theory-driven catalyst design.
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Affiliation(s)
- Jeffrey Greeley
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907;
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19
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Kudernatsch W, Peng G, Zeuthen H, Bai Y, Merte LR, Lammich L, Besenbacher F, Mavrikakis M, Wendt S. Direct Visualization of Catalytically Active Sites at the FeO-Pt(111) Interface. ACS NANO 2015; 9:7804-7814. [PMID: 26027877 DOI: 10.1021/acsnano.5b02339] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Within the area of surface science, one of the "holy grails" is to directly visualize a chemical reaction at the atomic scale. Whereas this goal has been reached by high-resolution scanning tunneling microscopy (STM) in a number of cases for reactions occurring at flat surfaces, such a direct view is often inhibited for reaction occurring at steps and interfaces. Here we have studied the CO oxidation reaction at the interface between ultrathin FeO islands and a Pt(111) support by in situ STM and density functional theory (DFT) calculations. Time-lapsed STM imaging on this inverse model catalyst in O2 and CO environments revealed catalytic activity occurring at the FeO-Pt(111) interface and directly showed that the Fe-edges host the catalytically most active sites for the CO oxidation reaction. This is an important result since previous evidence for the catalytic activity of the FeO-Pt(111) interface is essentially based on averaging techniques in conjunction with DFT calculations. The presented STM results are in accord with DFT+U calculations, in which we compare possible CO oxidation pathways on oxidized Fe-edges and O-edges. We found that the CO oxidation reaction is more favorable on the oxidized Fe-edges, both thermodynamically and kinetically.
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Affiliation(s)
- Wilhelmine Kudernatsch
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Guowen Peng
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Helene Zeuthen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Yunhai Bai
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Lindsay R Merte
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Lutz Lammich
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Flemming Besenbacher
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Stefan Wendt
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
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20
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Pan Q, Weng X, Chen M, Giordano L, Pacchioni G, Noguera C, Goniakowski J, Shaikhutdinov S, Freund HJ. Enhanced CO Oxidation on the Oxide/Metal Interface: From Ultra-High Vacuum to Near-Atmospheric Pressures. ChemCatChem 2015. [DOI: 10.1002/cctc.201500394] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Ni B, Wang X. Face the Edges: Catalytic Active Sites of Nanomaterials. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2015; 2:1500085. [PMID: 27980960 PMCID: PMC5115441 DOI: 10.1002/advs.201500085] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 04/19/2015] [Indexed: 05/07/2023]
Abstract
Edges are special sites in nanomaterials. The atoms residing on the edges have different environments compared to those in other parts of a nanomaterial and, therefore, they may have different properties. Here, recent progress in nanomaterial fields is summarized from the viewpoint of the edges. Typically, edge sites in MoS2 or metals, other than surface atoms, can perform as active centers for catalytic reactions, so the method to enhance performance lies in the optimization of the edge structures. The edges of multicomponent interfaces present even more possibilities to enhance the activities of nanomaterials. Nanoframes and ultrathin nanowires have similarities to conventional edges of nanoparticles, the application of which as catalysts can help to reduce the use of costly materials. Looking beyond this, the edge structures of graphene are also essential for their properties. In short, the edge structure can influence many properties of materials.
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Affiliation(s)
- Bing Ni
- Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Xun Wang
- Department of Chemistry Tsinghua University Beijing 100084 P. R. China
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