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da Silva Alvim R, Borges I, Alves RMB, Capaz RB, Leitão AA. CO adsorption on MgO thin-films: formation and interaction of surface charged defects. Phys Chem Chem Phys 2023; 25:28982-28997. [PMID: 37859503 DOI: 10.1039/d3cp03320a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Two-dimensional (2D) materials formed by thin-films of metal oxides that grow on metal supports are commonly used in heterogeneous catalysis and multilayer electronic devices. Despite extensive research on these systems, the effects of charged defects at supported oxides on surface processes are still not clear. In this work, we perform spin-polarized density-functional theory (DFT) calculations to investigate formation and interaction of charged magnesium and oxygen vacancies, and Al dopants on MgO(001)/Ag(001) surface. The results show a sizable interface compressive effect that decreases the metal work function as electrons are added on the MgO surface with a magnesium vacancy. This surface displays a larger formation energy in a water environment (O-rich condition) even with additional Al-doping. Under these conditions, we found that a polar molecule such as CO is more strongly adsorbed on the low-coordination oxygen sites due to a larger contribution of the channeled electronic transport with the silver interface regardless of the surface charge. Therefore, these findings elucidate how surface intrinsic vacancies can influence or contribute to charge transfer, which allows one to explore more specific reactions at different surface topologies for more efficient catalysts for CO2 conversion.
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Affiliation(s)
- Raphael da Silva Alvim
- Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo (USP), São Paulo, SP, 05508-900, Brazil.
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, 36036-330, Brazil
| | - Itamar Borges
- Departamento de Química, Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ, 22290-270, Brazil
| | - Rita Maria Brito Alves
- Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo (USP), São Paulo, SP, 05508-900, Brazil.
| | - Rodrigo B Capaz
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-972, Brazil
- Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, 13083-100, Brazil
| | - Alexandre Amaral Leitão
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, 36036-330, Brazil
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Abstract
The field of single-atom catalysis (SAC) has expanded greatly in recent years. While there has been much success developing new synthesis methods, a fundamental disconnect exists between most experiments and the theoretical computations used to model them. The real catalysts are based on powder supports, which inevitably contain a multitude of different facets, different surface sites, defects, hydroxyl groups, and other contaminants due to the environment. This makes it extremely difficult to determine the structure of the active SAC site using current techniques. To be tractable, computations aimed at modeling SAC utilize periodic boundary conditions and low-index facets of an idealized support. Thus, the reaction barriers and mechanisms determined computationally represent, at best, a plausibility argument, and there is a strong chance that some critical aspect is omitted. One way to better understand what is plausible is by experimental modeling, i.e., comparing the results of computations to experiments based on precisely defined single-crystalline supports prepared in an ultrahigh-vacuum (UHV) environment. In this review, we report the status of the surface-science literature as it pertains to SAC. We focus on experimental work on supports where the site of the metal atom are unambiguously determined from experiment, in particular, the surfaces of rutile and anatase TiO2, the iron oxides Fe2O3 and Fe3O4, as well as CeO2 and MgO. Much of this work is based on scanning probe microscopy in conjunction with spectroscopy, and we highlight the remarkably few studies in which metal atoms are stable on low-index surfaces of typical supports. In the Perspective section, we discuss the possibility for expanding such studies into other relevant supports.
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Affiliation(s)
- Florian Kraushofer
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
| | - Gareth S. Parkinson
- Institute of Applied Physics, Technische Universitat Wien, 1040 Vienna, Austria
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Pacchioni G, Rahman TS. Defect engineering of oxide surfaces: dream or reality? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:291501. [PMID: 35504272 DOI: 10.1088/1361-648x/ac6c6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/03/2022] [Indexed: 06/14/2023]
Abstract
In this brief perspective we analyze the present status of the field of defect engineering of oxide surfaces. In particular we discuss the tools and techniques available to generate, identify, quantify, and characterize point defects at oxide surfaces and the main areas where these centers play a role in practical applications.
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Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 202125, Milano, Italy
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- Renewable Energy and Chemical Transformation Cluster, University of Central Florida, Orlando, FL 32816, United States of America
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Adegoke KA, Maxakato NW. Porous metal oxide electrocatalytic nanomaterials for energy conversion: Oxygen defects and selection techniques. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214389] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tosoni S, Pacchioni G. Oxide‐Supported Gold Clusters and Nanoparticles in Catalysis: A Computational Chemistry Perspective. ChemCatChem 2018. [DOI: 10.1002/cctc.201801082] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Sergio Tosoni
- Dipartimento di Scienza dei MaterialiUniversità di Milano Bicocca Via Roberto Cozzi 55 Milano I-20125 Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei MaterialiUniversità di Milano Bicocca Via Roberto Cozzi 55 Milano I-20125 Italy
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Pacchioni G, Freund HJ. Controlling the charge state of supported nanoparticles in catalysis: lessons from model systems. Chem Soc Rev 2018; 47:8474-8502. [DOI: 10.1039/c8cs00152a] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Model systems are very important to identify the working principles of real catalysts, and to develop concepts that can be used in the design of new catalytic materials.
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Affiliation(s)
| | - Hans-Joachim Freund
- Fritz-Haber-Institut der Max-Planck-Gesellschaft
- Department of Chemical Physics
- 14195 Berlin
- Germany
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Schneider WD, Heyde M, Freund HJ. Charge Control in Model Catalysis: The Decisive Role of the Oxide-Nanoparticle Interface. Chemistry 2017; 24:2317-2327. [PMID: 28857287 DOI: 10.1002/chem.201703169] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Indexed: 11/06/2022]
Abstract
In chemistry and physics the electronic charge on a species or material is one important determinant of its properties. In the present Minireview, the essential requirements for a model catalyst system suitable to study charge control are discussed. The ideal model catalyst for this purpose consists of a material system, which comprises a single crystal metal support, covered by an epitaxially grown ultrathin oxide film, and flat, two-dimensional nanoparticles residing on this film. Several examples from the literature are selected and presented, which illustrate various aspects of electron transport from the support to the nanoparticle and vice versa. Key experiments demonstrate charge control within such model catalysts and give direct evidence for a chemical reaction at the perimeter of Au nanoparticles. The concepts derived from these studies are then taken a step further to see how they may be applied for bulk powder oxide supported nanoparticles as they are frequently found in catalytically active materials.
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Affiliation(s)
- Wolf-Dieter Schneider
- Department of Chemical Physics, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany
| | - Markus Heyde
- Department of Chemical Physics, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany
| | - Hans-Joachim Freund
- Department of Chemical Physics, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany
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Ruiz Puigdollers A, Schlexer P, Tosoni S, Pacchioni G. Increasing Oxide Reducibility: The Role of Metal/Oxide Interfaces in the Formation of Oxygen Vacancies. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01913] [Citation(s) in RCA: 423] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Antonio Ruiz Puigdollers
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi, 55 I-20125 Milano, Italy
| | - Philomena Schlexer
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi, 55 I-20125 Milano, Italy
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi, 55 I-20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi, 55 I-20125 Milano, Italy
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Altman EI, Baykara MZ, Schwarz UD. Noncontact Atomic Force Microscopy: An Emerging Tool for Fundamental Catalysis Research. Acc Chem Res 2015; 48:2640-8. [PMID: 26301490 DOI: 10.1021/acs.accounts.5b00166] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although atomic force microscopy (AFM) was rapidly adopted as a routine surface imaging apparatus after its introduction in 1986, it has not been widely used in catalysis research. The reason is that common AFM operating modes do not provide the atomic resolution required to follow catalytic processes; rather the more complex noncontact (NC) mode is needed. Thus, scanning tunneling microscopy has been the principal tool for atomic scale catalysis research. In this Account, recent developments in NC-AFM will be presented that offer significant advantages for gaining a complete atomic level view of catalysis. The main advantage of NC-AFM is that the image contrast is due to the very short-range chemical forces that are of interest in catalysis. This motivated our development of 3D-AFM, a method that yields quantitative atomic resolution images of the potential energy surfaces that govern how molecules approach, stick, diffuse, and rebound from surfaces. A variation of 3D-AFM allows the determination of forces required to push atoms and molecules on surfaces, from which diffusion barriers and variations in adsorption strength may be obtained. Pushing molecules towards each other provides access to intermolecular interaction between reaction partners. Following reaction, NC-AFM with CO-terminated tips yields textbook images of intramolecular structure that can be used to identify reaction intermediates and products. Because NC-AFM and STM contrast mechanisms are distinct, combining the two methods can produce unique insight. It is demonstrated for surface-oxidized Cu(100) that simultaneous 3D-AFM/STM yields resolution of both the Cu and O atoms. Moreover, atomic defects in the Cu sublattice lead to variations in the reactivity of the neighboring O atoms. It is shown that NC-AFM also allows a straightforward imaging of work function variations which has been used to identify defect charge states on catalytic surfaces and to map charge transfer within an individual molecule. These advances highlight the potential for NC-AFM-based methods to become the cornerstone upon which a quantitative atomic scale view of each step of a catalytic process may be gained. Realizing this potential will rely on two breakthroughs: (1) development of robust methods for tip functionalization and (2) simplification of NC-AFM instrumentation and control schemes. Quartz force sensors may offer paths forward in both cases. They allow any material with an atomic asperity to be used as a tip, opening the door to a wide range of surface functionalization chemistry. In addition, they do not suffer from the instabilities that motivated the initial adoption of complex control strategies that are still used today.
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Affiliation(s)
| | - Mehmet Z. Baykara
- Department
of Mechanical Engineering and UNAM − Institute of Materials
Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey
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Pacchioni G. Numerical Simulations of Defective Structures: The Nature of Oxygen Vacancy in Non-reducible (MgO, SiO2, ZrO2) and Reducible (TiO2, NiO, WO3) Oxides. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-3-319-14367-5_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Zhu J, Lin S, Wen X, Fang Z, Li Y, Zhang Y, Huang X, Ning L, Ding K, Chen W. Deposition of (WO3)3 nanoclusters on the MgO(001) surface: A possible way to identify the charge states of the defect centers. J Chem Phys 2013; 138:034711. [DOI: 10.1063/1.4776219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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12
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Pacchioni G. Electronic interactions and charge transfers of metal atoms and clusters on oxide surfaces. Phys Chem Chem Phys 2013; 15:1737-57. [DOI: 10.1039/c2cp43731g] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pacchioni G, Freund H. Electron Transfer at Oxide Surfaces. The MgO Paradigm: from Defects to Ultrathin Films. Chem Rev 2012; 113:4035-72. [DOI: 10.1021/cr3002017] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Gianfranco Pacchioni
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, Via R. Cozzi, 53−20125,
Milano, Italy
| | - Hajo Freund
- Fritz-Haber-Insitut
der MPG,
Department of Chemical Physics, Faradayweg 4-6, 14195 Berlin, Germany
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Kawai S, Canova FF, Glatzel T, Hynninen T, Meyer E, Foster AS. Measuring electric field induced subpicometer displacement of step edge ions. PHYSICAL REVIEW LETTERS 2012; 109:146101. [PMID: 23083258 DOI: 10.1103/physrevlett.109.146101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Indexed: 05/26/2023]
Abstract
We provide unambiguous evidence that the applied electrostatic field displaces step atoms of ionic crystal surfaces by subpicometers in different directions via the measurement of the lateral force interactions by bimodal dynamic force microscopy combined with multiscale theoretical simulations. Such a small imbalance in the electrostatic interaction of the shifted anion-cation ions leads to an extraordinary long-range feature potential variation and is now detectable with the extreme sensitivity of the bimodal detection.
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Affiliation(s)
- Shigeki Kawai
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
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15
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Liu JJ. Advanced Electron Microscopy of Metal-Support Interactions in Supported Metal Catalysts. ChemCatChem 2011. [DOI: 10.1002/cctc.201100090] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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16
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Ruminski AM, Jeon KJ, Urban JJ. Size-dependent CO2 capture in chemically synthesized magnesium oxide nanocrystals. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm11784j] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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