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Zhu B, Huang W, Lin H, Feng H, Palotás K, Lv J, Ren Y, Ouyang R, Yang F. Vacancy Ordering in Ultrathin Copper Oxide Films on Cu(111). J Am Chem Soc 2024; 146:15887-15896. [PMID: 38825776 DOI: 10.1021/jacs.4c02424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Oxide thin films grown on metal surfaces have wide applications in catalysis and beyond owing to their unique surface structures compared to their bulk counterparts. Despite extensive studies, the atomic structures of copper surface oxides on Cu(111), commonly referred to as "44" and "29", have remained elusive. In this work, we demonstrated an approach for the structural determination of oxide surfaces using element-specific scanning tunneling microscopy (STM) imaging enhanced by functionalized tips. This approach enabled us to resolve the atomic structures of "44" and "29" surface oxides, which were further corroborated by noncontact atomic force microscopy (nc-AFM) measurements and Monte Carlo (MC) simulations. The stoichiometry of the "44" and "29" frameworks was identified as Cu23O16 and Cu16O11, respectively. Contrary to the conventional hypothesis, we observed ordered Cu vacancies within the "44" structure manifesting as peanut-shaped cavities in the hexagonal lattice. Similarly, a combination of Cu and O vacancies within the "29" structure leads to bean-shaped cavities within the pentagonal lattice. Our study has thus resolved the decades-long controversy on the atomic structures of "44" and "29" surface oxides, advancing our understanding of copper oxidation processes and introducing a robust framework for the analysis of complex oxide surfaces.
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Affiliation(s)
- Bowen Zhu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wugen Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Haiping Lin
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China
| | - Hao Feng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | | | - Jiayu Lv
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yihui Ren
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Runhai Ouyang
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Fan Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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2
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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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3
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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. SCIENCE ADVANCES 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] [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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4
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Zhang L, Spezzati G, Muravev V, Verheijen MA, Zijlstra B, Filot IAW, Su YQ, Chang MW, Hensen EJM. Improved Pd/CeO 2 Catalysts for Low-Temperature NO Reduction: Activation of CeO 2 Lattice Oxygen by Fe Doping. ACS Catal 2021; 11:5614-5627. [PMID: 34055456 PMCID: PMC8154324 DOI: 10.1021/acscatal.1c00564] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/25/2021] [Indexed: 11/28/2022]
Abstract
Developing better three-way catalysts with improved low-temperature performance is essential for cold start emission control. Density functional theory in combination with microkinetics simulations is used to predict reactivity of CO/NO/H2 mixtures on a small Pd cluster on CeO2(111). At low temperatures, N2O formation occurs via a N2O2 dimer over metallic Pd3. Part of the N2O intermediate product re-oxidizes Pd, limiting NO conversion and requiring rich conditions to obtain high N2 selectivity. High N2 selectivity at elevated temperatures is due to N2O decomposition on oxygen vacancies. Doping CeO2 by Fe is predicted to lead to more oxygen vacancies and a higher N2 selectivity, which is validated by the lower onset of N2 formation for a Pd catalyst supported on Fe-doped CeO2 prepared by flame spray pyrolysis. Activating ceria surface oxygen by transition metal doping is a promising strategy to improve the performance of three-way catalysts.
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Affiliation(s)
- Long Zhang
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Giulia Spezzati
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Valery Muravev
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Marcel A. Verheijen
- Applied
Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Eurofins
Material Science Netherlands BV, 5656 AE Eindhoven, The Netherlands
| | - Bart Zijlstra
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ivo A. W. Filot
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ya-Qiong Su
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ming-Wen Chang
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Emiel J. M. Hensen
- Laboratory
of Inorganic Materials and Catalysis, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Chen Y, Sun H, Gates BC. Prototype Atomically Dispersed Supported Metal Catalysts: Iridium and Platinum. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2004665. [PMID: 33185034 DOI: 10.1002/smll.202004665] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/21/2020] [Indexed: 06/11/2023]
Abstract
When metal nanoparticles on supports are made smaller and smaller-to the limit of atomic dispersion-they become cationic and take on new catalytic properties that are only recently being discovered. The synthesis of these materials is reviewed, including their structure characterization-especially by atomic-resolution electron microscopy and X-ray absorption and infrared spectroscopies-and relationships between structure and catalyst performance, for reactions including hydrogenations, oxidations, and the water gas shift. Structure determination is challenging because of the intrinsic nonuniformity of the support surfaces-and therefore the structures on them-but fundamental understanding has advanced rapidly, benefiting from nearly uniform catalysts consisting of metals on well-defined-crystalline-supports and their characterization by spectroscopy and microscopy. Recent advances in atomic-resolution electron microscopy have spurred the field, providing stunning images and deep insights into structure. The iridium catalysts have typically been made from organoiridium precursors, opening the way to understanding and control of the metal-support bonding and ligands on the metal, including catalytic reaction intermediates. Platinum catalysts are usually made with less precision, from salt precursors, but they catalyze a wider array of reactions than the iridium, typically being stable at higher temperatures and seemingly offering rich prospect for discovery of new catalysts.
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Affiliation(s)
- Yizhen Chen
- Department of Chemical Engineering, University of California-Davis, Davis, CA, 95616, USA
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Hanlei Sun
- Department of Chemical Engineering, University of California-Davis, Davis, CA, 95616, USA
- Department of Chemical and Biochemical Engineering, Xiamen University, Xiamen, Fujian, 361005, P. R. China
| | - Bruce C Gates
- Department of Chemical Engineering, University of California-Davis, Davis, CA, 95616, USA
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6
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Qin F, Chen W. Copper-based single-atom alloys for heterogeneous catalysis. Chem Commun (Camb) 2021; 57:2710-2723. [PMID: 33616591 DOI: 10.1039/d1cc00062d] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Heterogeneous catalysts, as crucial industrial commodities, play an important role in industrial production, especially in energy catalysis. Traditional noble metal catalysts cannot meet the increasing demand. Therefore, the exploration of cost-effective catalysts with high activity and selectivity is important to promote chemical production. Single-atom alloy (SAA) catalysts reduce the use of precious metals compared with traditional catalysts. The unique structure of SAAs, extremely high atom utilization and high catalytic selectivity give them a prominent position in heterogeneous catalysis. SAAs are widely used in selective hydrogenation/dehydrogenation, carbon dioxide reduction reaction (CO2RR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and nitric oxide reduction reaction (NORR). Here, the applications and research progress of copper-based single-atom alloys in the various catalytic reactions mentioned above are mainly introduced, and the factors (such as synthesis method, composition content, etc.) affecting the catalytic performance are analyzed using a combination of various characterization and testing methods.
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Affiliation(s)
- Fengjuan Qin
- Energy & Catalysis Center, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Wenxing Chen
- Energy & Catalysis Center, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
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7
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Zhou J, Xu Z, Xu M, Zhou X, Wu K. A perspective on oxide-supported single-atom catalysts. NANOSCALE ADVANCES 2020; 2:3624-3631. [PMID: 36132800 PMCID: PMC9418980 DOI: 10.1039/d0na00393j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/14/2020] [Indexed: 06/16/2023]
Abstract
Single-atom catalysts (SACs) can not only maximize the metal atom utilization efficiency, but also show drastically improved catalytic performance for various important catalytic processes. Insights into the working principles of SACs provide rational guidance to design and prepare advanced catalysts. Many factors have been claimed to affect the performance of SACs, which makes it very challenging to clarify the correlation between the catalytic performance and physicochemical characteristics of SACs. Oxide-supported SACs are one of the most extensively explored systems. In this minireview, some latest developments on the determining factors of the stability, activity and selectivity of SACs on oxide supports are overviewed. Discussed also are the reaction mechanisms for different systems and methods that are employed to correlate the properties with the catalyst structures at the atomic level. In particular, a recently proposed surface free energy approach is introduced to fabricate well-defined modelled SACs that may help address some key issues in the development of SACs in the future.
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Affiliation(s)
- Junyi Zhou
- BNLMS, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Zhen Xu
- BNLMS, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Meijia Xu
- BNLMS, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Xiong Zhou
- BNLMS, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
| | - Kai Wu
- BNLMS, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 China
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8
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Li X, Yang X, Huang Y, Zhang T, Liu B. Supported Noble-Metal Single Atoms for Heterogeneous Catalysis. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902031. [PMID: 31282036 DOI: 10.1002/adma.201902031] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/16/2019] [Indexed: 05/24/2023]
Abstract
Single-atom catalysts (SACs), with atomically distributed active metal sites on supports, serve as a newly advanced material in catalysis, and open broad prospects for a wide variety of catalytic processes owing to their unique catalytic behaviors. To construct SACs with precise structures and high density of accessible single-atom sites, while preventing aggregation to large nanoparticles, various strategies for their chemical synthesis have been recently developed by improving the distribution and chemical bonding of active sites on supports, which results in excellent activity and selectivity in a variety of catalytic reactions. Noble-metal-based SACs are discussed, and their structural properties, chemical synthesis, and catalytic applications are highlighted. The structure-activity relationships and the underlying catalytic mechanisms are addressed, including the influences of surface species and reducibility of supports on the activity and stability, impact of the unique structural and electronic properties of single-atom centers modulated by metal/support interactions on catalytic activity and selectivity, and how the modified catalytic mechanism obtained by inhibiting the multiatoms involves catalytic pathways. Finally, the prospects and challenges for development in this field are highlighted.
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Affiliation(s)
- Xuning Li
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Xiaofeng Yang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Yanqiang Huang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Tao Zhang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bin Liu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
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9
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Lv J, Feng W, Yang S, Liu H, Huang X. Methanol dissociation and oxidation on single Fe atom supported on graphitic carbon nitride. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.4930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Junlan Lv
- Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational ChemistryJilin University Changchun 130023 China
| | - Wei Feng
- Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational ChemistryJilin University Changchun 130023 China
| | - Siwei Yang
- Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational ChemistryJilin University Changchun 130023 China
| | - Huiling Liu
- Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational ChemistryJilin University Changchun 130023 China
| | - Xuri Huang
- Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational ChemistryJilin University Changchun 130023 China
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10
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Parkinson GS. Single-Atom Catalysis: How Structure Influences Catalytic Performance. Catal Letters 2019; 149:1137-1146. [PMID: 30971855 PMCID: PMC6432890 DOI: 10.1007/s10562-019-02709-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 02/05/2019] [Indexed: 02/01/2023]
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