1
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Zang W, Lee J, Tieu P, Yan X, Graham GW, Tran IC, Wang P, Christopher P, Pan X. Distribution of Pt single atom coordination environments on anatase TiO 2 supports controls reactivity. Nat Commun 2024; 15:998. [PMID: 38307931 PMCID: PMC10837418 DOI: 10.1038/s41467-024-45367-z] [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: 09/01/2023] [Accepted: 01/18/2024] [Indexed: 02/04/2024] Open
Abstract
Single-atom catalysts (SACs) offer efficient metal utilization and distinct reactivity compared to supported metal nanoparticles. Structure-function relationships for SACs often assume that active sites have uniform coordination environments at particular binding sites on support surfaces. Here, we investigate the distribution of coordination environments of Pt SAs dispersed on shape-controlled anatase TiO2 supports specifically exposing (001) and (101) surfaces. Pt SAs on (101) are found on the surface, consistent with existing structural models, whereas those on (001) are beneath the surface after calcination. Pt SAs under (001) surfaces exhibit lower reactivity for CO oxidation than those on (101) surfaces due to their limited accessibility to gas phase species. Pt SAs deposited on commercial-TiO2 are found both at the surface and in the bulk, posing challenges to structure-function relationship development. This study highlights heterogeneity in SA coordination environments on oxide supports, emphasizing a previously overlooked consideration in the design of SACs.
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Affiliation(s)
- Wenjie Zang
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - Jaeha Lee
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Peter Tieu
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
| | - George W Graham
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ich C Tran
- Irvine Materials Research Institute, University of California, Irvine, CA, 92697, USA
| | - Peikui Wang
- Department of Chemistry, University of Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California, Irvine, CA, 92697, USA.
- Irvine Materials Research Institute, University of California, Irvine, CA, 92697, USA.
- Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA.
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2
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Affiliation(s)
- Xinyu Mao
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Chao Lin
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - George W. Graham
- Department of Materials Science and Engineering, University of California Irvine, Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Raymond J. Gorte
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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3
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Resasco J, DeRita L, Dai S, Chada JP, Xu M, Yan X, Finzel J, Hanukovich S, Hoffman AS, Graham GW, Bare SR, Pan X, Christopher P. Uniformity Is Key in Defining Structure–Function Relationships for Atomically Dispersed Metal Catalysts: The Case of Pt/CeO2. J Am Chem Soc 2019; 142:169-184. [DOI: 10.1021/jacs.9b09156] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Joaquin Resasco
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Leo DeRita
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | | | - Joseph P. Chada
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Mingjie Xu
- Fok Ying Tung Research Institute, Hong Kong University of Science and Technology, Guangzhou 511458, PR China
| | | | - Jordan Finzel
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Sergei Hanukovich
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Adam S. Hoffman
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - George W. Graham
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Simon R. Bare
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | | | - Phillip Christopher
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
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4
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Ro I, Xu M, Graham GW, Pan X, Christopher P. Synthesis of Heteroatom Rh–ReOx Atomically Dispersed Species on Al2O3 and Their Tunable Catalytic Reactivity in Ethylene Hydroformylation. ACS Catal 2019. [DOI: 10.1021/acscatal.9b02111] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Insoo Ro
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, United States
- Department of Chemical and Biomolecular Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | | | - George W. Graham
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, United States
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5
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Tang Y, Asokan C, Xu M, Graham GW, Pan X, Christopher P, Li J, Sautet P. Rh single atoms on TiO 2 dynamically respond to reaction conditions by adapting their site. Nat Commun 2019; 10:4488. [PMID: 31582746 PMCID: PMC6776542 DOI: 10.1038/s41467-019-12461-6] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [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: 06/16/2019] [Accepted: 09/11/2019] [Indexed: 11/24/2022] Open
Abstract
Single-atom catalysts are widely investigated heterogeneous catalysts; however, the identification of the local environment of single atoms under experimental conditions, as well as operando characterization of their structural changes during catalytic reactions are still challenging. Here, the preferred local coordination of Rh single atoms is investigated on TiO2 during calcination in O2, reduction in H2, CO adsorption, and reverse water gas shift (RWGS) reaction conditions. Theoretical and experimental studies clearly demonstrate that Rh single atoms adapt their local coordination and reactivity in response to various redox conditions. Single-atom catalysts hence do not have static local coordinations, but can switch from inactive to active structure under reaction conditions, hence explaining some conflicting literature accounts. The combination of approaches also elucidates the structure of the catalytic active site during reverse water gas shift. This insight on the real nature of the active site is key for the design of high-performance catalysts. Single-atom catalysts are widely investigated heterogeneous catalysts; however, the identification of the local environment of single atoms under experimental conditions is still challenging. Here, the authors clearly demonstrate that Rh single atoms adapt their local coordination and reactivity in response to various redox conditions.
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Affiliation(s)
- Yan Tang
- Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, 100084, Beijing, China.,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Chithra Asokan
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Mingjie Xu
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, 92697, USA
| | - George W Graham
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, 92697, USA.,Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, 92697, USA.,Department of Physics and Astronomy, University of California Irvine, Irvine, CA, 92697, USA.,Irvine Materials Research Institute (IMRI), University of California Irvine, Irvine, CA, 92697, USA
| | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Jun Li
- Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, 100084, Beijing, China. .,Department of Chemistry, Southern University of Science and Technology, 518055, Shenzhen, China.
| | - Philippe Sautet
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA. .,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA. .,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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6
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DeRita L, Resasco J, Dai S, Boubnov A, Thang HV, Hoffman AS, Ro I, Graham GW, Bare SR, Pacchioni G, Pan X, Christopher P. Structural evolution of atomically dispersed Pt catalysts dictates reactivity. Nat Mater 2019; 18:746-751. [PMID: 31011216 DOI: 10.1038/s41563-019-0349-9] [Citation(s) in RCA: 250] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/15/2019] [Indexed: 05/20/2023]
Abstract
The use of oxide-supported isolated Pt-group metal atoms as catalytic active sites is of interest due to their unique reactivity and efficient metal utilization. However, relationships between the structure of these active sites, their dynamic response to environments and catalytic functionality have proved difficult to experimentally establish. Here, sinter-resistant catalysts where Pt was deposited uniformly as isolated atoms in well-defined locations on anatase TiO2 nanoparticle supports were used to develop such relationships. Through a combination of in situ atomic-resolution microscopy- and spectroscopy-based characterization supported by first-principles calculations it was demonstrated that isolated Pt species can adopt a range of local coordination environments and oxidation states, which evolve in response to varied environmental conditions. The variation in local coordination showed a strong influence on the chemical reactivity and could be exploited to control the catalytic performance.
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Affiliation(s)
- Leo DeRita
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Joaquin Resasco
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Sheng Dai
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA
| | - Alexey Boubnov
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Ho Viet Thang
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Milano, Italy
| | - Adam S Hoffman
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Insoo Ro
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, USA
| | - George W Graham
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Simon R Bare
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Milano, Italy
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, USA
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
- Irvine Materials Research Institute (IMRI), University of California Irvine, Irvine, CA, USA
| | - Phillip Christopher
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, USA.
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7
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Onn TM, Monai M, Dai S, Fonda E, Montini T, Pan X, Graham GW, Fornasiero P, Gorte RJ. Smart Pd Catalyst with Improved Thermal Stability Supported on High-Surface-Area LaFeO3 Prepared by Atomic Layer Deposition. J Am Chem Soc 2018; 140:4841-4848. [DOI: 10.1021/jacs.7b12900] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tzia Ming Onn
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Matteo Monai
- Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR, Consortium INSTM, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Sheng Dai
- Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697, United States
| | - Emiliano Fonda
- SAMBA Beamline, Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif sur Yvette Cedex, France
| | - Tiziano Montini
- Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR, Consortium INSTM, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697, United States
- Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - George W. Graham
- Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697, United States
| | - Paolo Fornasiero
- Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR, Consortium INSTM, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Raymond J. Gorte
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
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8
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DeRita L, Dai S, Lopez-Zepeda K, Pham N, Graham GW, Pan X, Christopher P. Catalyst Architecture for Stable Single Atom Dispersion Enables Site-Specific Spectroscopic and Reactivity Measurements of CO Adsorbed to Pt Atoms, Oxidized Pt Clusters, and Metallic Pt Clusters on TiO2. J Am Chem Soc 2017; 139:14150-14165. [DOI: 10.1021/jacs.7b07093] [Citation(s) in RCA: 390] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Leo DeRita
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Sheng Dai
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Kimberly Lopez-Zepeda
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Nicholas Pham
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - George W. Graham
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Xiaoqing Pan
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
| | - Phillip Christopher
- Department
of Chemical and Environmental Engineering, ‡Program in Materials
Science and Engineering, and §UCR Center for Catalysis, University of California Riverside, Riverside, California 92521, United States
- Department of Chemical Engineering and Materials Science and ⊥Department of
Physics and Astronomy, University of California Irvine, Irvine, California 92697, United States
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9
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Dai S, Hou Y, Onoue M, Zhang S, Gao W, Yan X, Graham GW, Wu R, Pan X. Revealing Surface Elemental Composition and Dynamic Processes Involved in Facet-Dependent Oxidation of Pt 3Co Nanoparticles via in Situ Transmission Electron Microscopy. Nano Lett 2017; 17:4683-4688. [PMID: 28686034 DOI: 10.1021/acs.nanolett.7b01325] [Citation(s) in RCA: 23] [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] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Since catalytic performance of platinum-metal (Pt-M) nanoparticles is primarily determined by the chemical and structural configurations of the outermost atomic layers, detailed knowledge of the distribution of Pt and M surface atoms is crucial for the design of Pt-M electrocatalysts with optimum activity. Further, an understanding of how the surface composition and structure of electrocatalysts may be controlled by external means is useful for their efficient production. Here, we report our study of surface composition and the dynamics involved in facet-dependent oxidation of equilibrium-shaped Pt3Co nanoparticles in an initially disordered state via in situ transmission electron microscopy and density functional calculations. In brief, using our advanced in situ gas cell technique, evolution of the surface of the Pt3Co nanoparticles was monitored at the atomic scale during their exposure to an oxygen atmosphere at elevated temperature, and it was found that Co segregation and oxidation take place on {111} surfaces but not on {100} surfaces.
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Affiliation(s)
- Sheng Dai
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
| | - Yusheng Hou
- Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States
| | - Masatoshi Onoue
- Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States
| | - Shuyi Zhang
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Wenpei Gao
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
| | - Xingxu Yan
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
| | - George W Graham
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States
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10
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Dai S, You Y, Zhang S, Cai W, Xu M, Xie L, Wu R, Graham GW, Pan X. In situ atomic-scale observation of oxygen-driven core-shell formation in Pt 3Co nanoparticles. Nat Commun 2017; 8:204. [PMID: 28785077 PMCID: PMC5547122 DOI: 10.1038/s41467-017-00161-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [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: 07/31/2016] [Accepted: 06/06/2017] [Indexed: 11/09/2022] Open
Abstract
The catalytic performance of core-shell platinum alloy nanoparticles is typically superior to that of pure platinum nanoparticles for the oxygen reduction reaction in fuel cell cathodes. Thorough understanding of core-shell formation is critical for atomic-scale design and control of the platinum shell, which is known to be the structural feature responsible for the enhancement. Here we reveal details of a counter-intuitive core-shell formation process in platinum-cobalt nanoparticles at elevated temperature under oxygen at atmospheric pressure, by using advanced in situ electron microscopy. Initial segregation of a thin platinum, rather than cobalt oxide, surface layer occurs concurrently with ordering of the intermetallic core, followed by the layer-by-layer growth of a platinum shell via Ostwald ripening during the oxygen annealing treatment. Calculations based on density functional theory demonstrate that this process follows an energetically favourable path. These findings are expected to be useful for the future design of structured platinum alloy nanocatalysts. Core-shell platinum alloy nanoparticles are promising catalysts for oxygen reduction, however a deeper understanding of core-shell formation is still required. Here the authors report oxygen-driven formation of core-shell Pt3Co nanoparticles, seen at the atomic scale with in situ electron microscopy at ambient pressure.
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Affiliation(s)
- Sheng Dai
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA
| | - Yuan You
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, 92697, USA.,School of Physics and Electronics, Yancheng Teachers University, Yancheng, Jiangsu, 224002, China
| | - Shuyi Zhang
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA.,Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Wei Cai
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mingjie Xu
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA.,Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Lin Xie
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA.,National Laboratory of Solid State Microstructures and College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210094, P.R. China
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, 92697, USA
| | - George W Graham
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA.,Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California Irvine, Irvine, CA, 92697, USA. .,Department of Physics and Astronomy, University of California Irvine, Irvine, CA, 92697, USA.
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11
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Goodman ED, Dai S, Yang AC, Wrasman CJ, Gallo A, Bare SR, Hoffman AS, Jaramillo TF, Graham GW, Pan X, Cargnello M. Uniform Pt/Pd Bimetallic Nanocrystals Demonstrate Platinum Effect on Palladium Methane Combustion Activity and Stability. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00393] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Emmett D. Goodman
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
| | - Sheng Dai
- Department
of Chemical Engineering and Materials Science, University of California—Irvine, Irvine, California 92697, United States
| | - An-Chih Yang
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
| | - Cody J. Wrasman
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
| | - Alessandro Gallo
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
- Stanford
Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Simon R. Bare
- Stanford
Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Adam S. Hoffman
- Stanford
Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Thomas F. Jaramillo
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
| | - George W. Graham
- Department
of Chemical Engineering and Materials Science, University of California—Irvine, Irvine, California 92697, United States
| | - Xiaoqing Pan
- Department
of Chemical Engineering and Materials Science, University of California—Irvine, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of California—Irvine, Irvine, California 92697, United States
| | - Matteo Cargnello
- Department
of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, United States
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12
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Avanesian T, Dai S, Kale MJ, Graham GW, Pan X, Christopher P. Quantitative and Atomic-Scale View of CO-Induced Pt Nanoparticle Surface Reconstruction at Saturation Coverage via DFT Calculations Coupled with in Situ TEM and IR. J Am Chem Soc 2017; 139:4551-4558. [PMID: 28263592 DOI: 10.1021/jacs.7b01081] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Atomic-scale insights into how supported metal nanoparticles catalyze chemical reactions are critical for the optimization of chemical conversion processes. It is well-known that different geometric configurations of surface atoms on supported metal nanoparticles have different catalytic reactivity and that the adsorption of reactive species can cause reconstruction of metal surfaces. Thus, characterizing metallic surface structures under reaction conditions at atomic scale is critical for understanding reactivity. Elucidation of such insights on high surface area oxide supported metal nanoparticles has been limited by less than atomic resolution typically achieved by environmental transmission electron microscopy (TEM) when operated under realistic conditions and a lack of correlated experimental measurements providing quantitative information about the distribution of exposed surface atoms under relevant reaction conditions. We overcome these limitations by correlating density functional theory predictions of adsorbate-induced surface reconstruction visually with atom-resolved imaging by in situ TEM and quantitatively with sample-averaged measurements of surface atom configurations by in situ infrared spectroscopy all at identical saturation adsorbate coverage. This is demonstrated for platinum (Pt) nanoparticle surface reconstruction induced by CO adsorption at saturation coverage and elevated (>400 K) temperature, which is relevant for the CO oxidation reaction under cold-start conditions in the catalytic convertor. Through our correlated approach, it is observed that the truncated octahedron shape adopted by bare Pt nanoparticles undergoes a reversible, facet selective reconstruction due to saturation CO coverage, where {100} facets roughen into vicinal stepped high Miller index facets, while {111} facets remain intact.
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Affiliation(s)
- Talin Avanesian
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
| | - Sheng Dai
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
| | - Matthew J Kale
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
| | - George W Graham
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
| | - Xiaoqing Pan
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
| | - Phillip Christopher
- Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.,Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States
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13
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Dai S, Zhang S, Katz MB, Graham GW, Pan X. In Situ Observation of Rh-CaTiO3 Catalysts during Reduction and Oxidation Treatments by Transmission Electron Microscopy. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03604] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sheng Dai
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
| | - Shuyi Zhang
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Michael B. Katz
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Materials
Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - George W. Graham
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Xiaoqing Pan
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of California−Irvine, Irvine, California 92697, United States
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14
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Matsubu JC, Zhang S, DeRita L, Marinkovic NS, Chen JG, Graham GW, Pan X, Christopher P. Adsorbate-mediated strong metal–support interactions in oxide-supported Rh catalysts. Nat Chem 2016; 9:120-127. [DOI: 10.1038/nchem.2607] [Citation(s) in RCA: 442] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 08/05/2016] [Indexed: 12/24/2022]
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15
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Zhang S, Plessow PN, Willis JJ, Dai S, Xu M, Graham GW, Cargnello M, Abild-Pedersen F, Pan X. Dynamical Observation and Detailed Description of Catalysts under Strong Metal-Support Interaction. Nano Lett 2016; 16:4528-34. [PMID: 27280326 DOI: 10.1021/acs.nanolett.6b01769] [Citation(s) in RCA: 144] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Understanding the structures of catalysts under realistic conditions with atomic precision is crucial to design better materials for challenging transformations. Under reducing conditions, certain reducible supports migrate onto supported metallic particles and create strong metal-support states that drastically change the reactivity of the systems. The details of this process are still unclear and preclude its thorough exploitation. Here, we report an atomic description of a palladium/titania (Pd/TiO2) system by combining state-of-the-art in situ transmission electron microscopy and density functional theory (DFT) calculations with structurally defined materials, in which we visualize the formation of the overlayers at the atomic scale under atmospheric pressure and high temperature. We show that an amorphous reduced titania layer is formed at low temperatures, and that crystallization of the layer into either mono- or bilayer structures is dictated by the reaction environment and predicted by theory. Furthermore, it occurs in combination with a dramatic reshaping of the metallic surface facets.
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Affiliation(s)
- Shuyi Zhang
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Philipp N Plessow
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States
| | - Joshua J Willis
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States
| | - Sheng Dai
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Mingjie Xu
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - George W Graham
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University , Stanford, California 94305, United States
| | - Frank Abild-Pedersen
- SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science, University of California-Irvine , Irvine, California 92697, United States
- Department of Physics and Astronomy, University of California-Irvine , Irvine, California 92697, United States
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Zhang S, Cargnello M, Cai W, Murray CB, Graham GW, Pan X. Revealing particle growth mechanisms by combining high-surface-area catalysts made with monodisperse particles and electron microscopy conducted at atmospheric pressure. J Catal 2016. [DOI: 10.1016/j.jcat.2016.02.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Malamis SA, Harrington RJ, Katz MB, Koerschner DS, Zhang S, Cheng Y, Xu L, Jen HW, McCabe RW, Graham GW, Pan X. Comparison of precious metal doped and impregnated perovskite oxides for TWC application. Catal Today 2015. [DOI: 10.1016/j.cattod.2014.11.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Onn TM, Zhang S, Arroyo-Ramirez L, Chung YC, Graham GW, Pan X, Gorte RJ. Improved Thermal Stability and Methane-Oxidation Activity of Pd/Al2O3 Catalysts by Atomic Layer Deposition of ZrO2. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01348] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tzia Ming Onn
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Shuyi Zhang
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
| | - Lisandra Arroyo-Ramirez
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Yu-Chieh Chung
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - George W. Graham
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Xiaoqing Pan
- Department
of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department
of Chemical Engineering and Materials Science, University of California−Irvine, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of California−Irvine, Irvine, California 92697, United States
| | - Raymond J. Gorte
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, Pennsylvania 19104, United States
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Zhang K, Du X, Katz MB, Li B, Kim SJ, Song K, Graham GW, Pan X. Creating high quality Ca:TiO2-B (CaTi5O11) and TiO2-B epitaxial thin films by pulsed laser deposition. Chem Commun (Camb) 2015; 51:8584-7. [DOI: 10.1039/c5cc01878a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Highly crystalline TiO2-B/Ca:TiO2-B dual layer fabricated by pulsed laser deposition.
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Affiliation(s)
- Kui Zhang
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
- Department of Chemical Engineering and Materials Science
| | - Xianfeng Du
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - Michael B. Katz
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - Baihai Li
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - Sung Joo Kim
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - Kaixin Song
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - George W. Graham
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor
- USA
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science
- University of California – Irvine
- Irvine
- USA
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Kim SJ, Zhang K, Katz MB, Li B, Graham GW, Pan X. Atomic structure of defects and interfaces in TiO2-B and Ca:TiO2-B (CaTi5O11) films grown on SrTiO3. CrystEngComm 2015. [DOI: 10.1039/c5ce00493d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An atomic-scale analysis of the interfacial structure and defects in CaTi5O11grown on SrTiO3and TiO2-B grown on CaTi5O11is presented.
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Affiliation(s)
- Sung Joo Kim
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor, USA
| | - Kui Zhang
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor, USA
- Department of Chemical Engineering and Materials Science and Department of Physics and Astronomy
- University of California - Irvine
| | - Michael B. Katz
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor, USA
| | - Baihai Li
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor, USA
| | - George W. Graham
- Department of Materials Science and Engineering
- University of Michigan
- Ann Arbor, USA
| | - Xiaoqing Pan
- Department of Chemical Engineering and Materials Science and Department of Physics and Astronomy
- University of California - Irvine
- Irvine, USA
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21
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Zhang K, Katz MB, Li B, Kim SJ, Du X, Hao X, Jokisaari JR, Zhang S, Graham GW, Van der Ven A, Bartlett BM, Pan X. Water-free titania-bronze thin films with superfast lithium-ion transport. Adv Mater 2014; 26:7365-7370. [PMID: 25244308 DOI: 10.1002/adma.201401757] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/14/2014] [Indexed: 06/03/2023]
Abstract
Using pulsed laser deposition, TiO2 (-) B and its recently discovered variant Ca:TiO2 (-) B (CaTi5O11) are synthesized as highly crystalline thin films for the first time by a completely water-free process. Significant enhancement in the Li-ion battery performance is achieved by manipulating the crystal orientation of the films, used as anodes, with a demonstration of extraordinary structural stability under extreme conditions.
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Affiliation(s)
- Kui Zhang
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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Kim SJ, Noh SY, Kargar A, Wang D, Graham GW, Pan X. In situ TEM observation of the structural transformation of rutile TiO2nanowire during electrochemical lithiation. Chem Commun (Camb) 2014; 50:9932-5. [DOI: 10.1039/c4cc04161e] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Davies EJ, McKee D, Bowers D, Graham GW, Nimmo-Smith WAM. Optically significant particle sizes in seawater. Appl Opt 2014; 53:1067-1074. [PMID: 24663303 DOI: 10.1364/ao.53.001067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/15/2014] [Indexed: 06/03/2023]
Abstract
Small particles (<10 μm) are often considered to play the dominant role in controlling scattering and absorption due to their relatively large numbers, which are typically found in the ocean. Here we present an approach for quantifying the size range of particles that contribute significantly to bulk inherent optical properties. We present a numerical assessment of the variability in optically significant particle sizes for simplistic populations that conform to the assumptions of homogeneous, spherical particles, and power-law size distributions. We use numerical predictions from Mie theory to suggest minimum and maximum particle sizes required for accurate predictions and observations of ocean optics for different particle size distributions (PSDs). When considering observed ranges of PSDs, our predictions suggest the need for measurements of optical properties and particles to capture information from particle sizes between diameters of 0.05-2000 μm in order to properly constrain relationships between particles and their associated optical properties. Natural particle populations in the ocean may present more complex PSDs that could be analyzed using the method presented here to establish optically significant size classes.
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Li B, Katz MB, Zhang Q, Chen L, Graham GW, Pan X. Surface-termination-dependent Pd bonding and aggregation of nanoparticles on LaFeO3 (001). J Chem Phys 2013; 138:144705. [DOI: 10.1063/1.4798636] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Katz MB, Zhang S, Duan Y, Wang H, Fang M, Zhang K, Li B, Graham GW, Pan X. Reversible precipitation/dissolution of precious-metal clusters in perovskite-based catalyst materials: Bulk versus surface re-dispersion. J Catal 2012. [DOI: 10.1016/j.jcat.2012.06.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Katz MB, Graham GW, Duan Y, Liu H, Adamo C, Schlom DG, Pan X. Self-Regeneration of Pd–LaFeO3 Catalysts: New Insight from Atomic-Resolution Electron Microscopy. J Am Chem Soc 2011; 133:18090-3. [DOI: 10.1021/ja2082284] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael B. Katz
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - George W. Graham
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yingwen Duan
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hong Liu
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Carolina Adamo
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Darrell G. Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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27
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Alexeev OS, Graham GW, Shelef M, Adams RD, Gates BC. γ-Al2O3-Supported PtRu Clusters Prepared from [Pt2Ru4(CO)18]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies. J Phys Chem B 2002. [DOI: 10.1021/jp014342i] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oleg S. Alexeev
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, Ford Research Laboratory, Ford Motor Co., Dearborn, Michigan 48121, and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - George W. Graham
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, Ford Research Laboratory, Ford Motor Co., Dearborn, Michigan 48121, and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Mordecai Shelef
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, Ford Research Laboratory, Ford Motor Co., Dearborn, Michigan 48121, and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Richard D. Adams
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, Ford Research Laboratory, Ford Motor Co., Dearborn, Michigan 48121, and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Bruce C. Gates
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, Ford Research Laboratory, Ford Motor Co., Dearborn, Michigan 48121, and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
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Abstract
Anesthesiologists routinely encounter patients with endocrine disorders. Good perioperative outcome depends on preoperative identification, risk stratification and optimization of the patients' endocrinopathies and their sequelae; intraoperative control of metabolic and physiological parameters; and appropriate postoperative pain management, stress modulation, and evaluation of neurological, cardiovascular, and renal function.
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Affiliation(s)
- G W Graham
- Department of Anesthesiology, University of Wisconsin Hospitals and Clinics, Madison 53792, USA
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Lai F, Kim DW, Alexeev OS, Graham GW, Shelef M, Gates BC. Temperature programmed desorption of hydrogen from γ-Al2O3-supported platinum catalysts with and without tungsten. Phys Chem Chem Phys 2000. [DOI: 10.1039/b000842g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Alexeev OS, Graham GW, Kim DW, Shelef M, Gates BC. γ-Al2O3-supported Pt–W catalysts prepared from molecular organometallic precursors: Characterization by infrared spectroscopy. Phys Chem Chem Phys 1999. [DOI: 10.1039/a907022b] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Fifteen pregnancies at risk for Lesch-Nyhan syndrome were investigated between 8 and 17 weeks' gestation by measurement of hypoxanthine-guanine phosphoribosyl transferase (HGPRT) and adenine phosphoribosyl transferase (APRT) enzyme activities in chorionic villus samples (cultured and uncultured) or in cultured amniotic fluid cells. Ten pregnancies had normal enzyme levels and a normal outcome while a further two predicted to be normal miscarried later in the pregnancy. Three pregnancies had low levels of residual HGPRT activity in chorionic villi. Comparable levels of residual activity in the index case in two pregnancies and in cells from the abortus in the third case confirmed that the pregnancies were affected.
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Affiliation(s)
- G W Graham
- Duncan Guthrie Institute of Medical Genetics, Yorkhill, Glasgow, UK
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Graham GW, Crossley JA, Aitken DA, Connor JM. Variation in the levels of pregnancy-specific beta-1-glycoprotein in maternal serum from chromosomally abnormal pregnancies. Prenat Diagn 1992; 12:505-12. [PMID: 1387478 DOI: 10.1002/pd.1970120605] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human pregnancy-specific beta-1-glycoprotein (SP1) was assayed retrospectively in stored maternal serum (MS) samples from 82 chromosomally abnormal pregnancies and 377 matched controls. The median MSSP1 concentration in 48 Down's syndrome pregnancies was significantly elevated at 1.17 multiples of the control median (MOM), and significantly reduced (0.5 MOM) in a group of eight cases of unbalanced translocations. There was no significant difference in median SP1 concentrations in cases of trisomy 18, trisomy 13, balanced translocations, or sex chromosome abnormalities. A comparison with human chorionic gonadotrophin results in the same series of samples indicates that SP1 is a less sensitive predictor of Down's syndrome pregnancies.
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Affiliation(s)
- G W Graham
- Duncan Guthrie Institute of Medical Genetics, Yorkhill, Glasgow, U.K
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Pope TD, Anderson GW, Griffiths K, Norton PR, Graham GW. Coverage and structure of ultrathin Pd films on Cu(100). Phys Rev B Condens Matter 1991; 44:11518-11520. [PMID: 9999281 DOI: 10.1103/physrevb.44.11518] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Weber WH, Graham GW, McBride JR. Raman spectrum of beta -PtO2: Evidence for the D2h12-to-D4h14 phase transition. Phys Rev B Condens Matter 1990; 42:10969-10975. [PMID: 9995374 DOI: 10.1103/physrevb.42.10969] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Schmitz PJ, Leung W, Graham GW, Thiel PA. Novel metal-film configuration: Rh on Ag(100). Phys Rev B Condens Matter 1989; 40:11477-11487. [PMID: 9991744 DOI: 10.1103/physrevb.40.11477] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Zeitune M, Aitken DA, Graham GW, Crossley JA, Ferguson-Smith MA. Amniotic fluid alpha-fetoprotein, gamma-glutamyltranspeptidase, and autosomal trisomies. Prenat Diagn 1989; 9:559-68. [PMID: 2477836 DOI: 10.1002/pd.1970090805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Alpha-fetoprotein (AFP) concentration and gamma-glutamyltranspeptidase (GGT) activity have been analysed in amniotic fluid from a series of 65 pregnancies with autosomal trisomies. AFP values were reduced on average to 60 per cent of normal in cases of trisomy 21, but were not significantly different from normal in cases of trisomies 18 and 13. GGT activities were uniformly lower (44 per cent of normal) for all types of autosomal trisomy. A review of the literature indicates that over 85 per cent of Down's pregnancies but only 39 per cent of trisomy 18 and 13 pregnancies have amniotic fluid AFP levels below the normal median value, while the corresponding figures for GGT are 91 per cent for Down's syndrome and 96 per cent for trisomies 18 and 13.
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Affiliation(s)
- M Zeitune
- Duncan Guthrie Institute of Medical Genetics, Yorkhill, Glasgow, U.K
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Abstract
Blood was collected simultaneously from the left ventricle and pulmonary artery in 12 patients undergoing routine cardiac catheterisation and was analysed for noradrenaline concentrations at rest, during, and after isometric stress (hand grip). Moderate isometric exercise resulted in a significant rise in plasma noradrenaline with a return to basal values 10 minutes after discontinuing the grip test. There were no significant differences in noradrenaline levels between the left ventricular and pulmonary arterial samples either at rest or during exercise. Three patients with evident left ventricular dysfunction had the highest plasma noradrenaline concentrations, in contrast to the much lower levels in 2 patients on beta-blockers and in 1 patient with a normal heart. As moderate isometric effort results in an important increase in noradrenaline level, this form of exercise could be dangerous in subjects suffering from ischaemic heart disease or in those with impaired left ventricular function since these patients are particularly susceptible to arrhythmias.
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Graham GW. Accountability through corporate responsibility in community hospitals. AHME J 1976; 8:10. [PMID: 10237059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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42
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Hague JE, Graham GW. George Wm. Graham, M.D.; recipient of the 1974 Distinguished Service Award of the American Hospital Association. Hospitals 1974; 48:56-61. [PMID: 4606584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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43
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Graham GW. The Presidential address. Hospitals 1969; 43:55-9. [PMID: 4898780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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44
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Graham GW. Inaugural address. Hospitals 1968; 42:59-63. [PMID: 5688331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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