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An H, Ha H, Yoo M, Kim HY. Understanding the atomic-level process of CO-adsorption-driven surface segregation of Pd in (AuPd) 147 bimetallic nanoparticles. NANOSCALE 2017; 9:12077-12086. [PMID: 28799609 DOI: 10.1039/c7nr04435f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
When the elements that compose bimetallic catalysts interact asymmetrically with reaction feedstock, the surface concentration of the bimetallic catalysts and the morphology of the reaction center evolve dynamically as a function of environmental factors such as the partial pressure of the triggering molecule. Relevant experimental and theoretical findings of the dynamic structural evolution of bimetallic catalysts under the reaction conditions are emerging, thus enabling the design of more consistent, reliable, and efficient bimetallic catalysts. In an initial attempt to provide an atomic-level understanding of the adsorption-induced structural evolution of bimetallic nanoparticles (NPs) under CO oxidation conditions, we used density functional theory to study the details of CO-adsorption-driven Pd surface segregation in (AuPd)147 bimetallic NPs. The strong CO affinity of Pd provides a driving force for Pd surface segregation. We found that the vertex site of the NP becomes a gateway for the initial Pd-Au swapping and the subsequent formation of an internal vacancy. This self-generated internal vacancy easily diffuses inside the NP and activates Pd-Au swapping pathways in the (100) NP facet. Our results reveal how the surface and internal concentrations of bimetallic NPs respond immediately to changes in the reaction conditions. Our findings should aid in the rational design of highly active and versatile bimetallic catalysts by considering the environmental factors that systematically affect the structure of bimetallic catalysts under the reaction conditions.
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Affiliation(s)
- Hyesung An
- Department of Materials Science and Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
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Prasai B, Wilson AR, Wiley BJ, Ren Y, Petkov V. On the road to metallic nanoparticles by rational design: bridging the gap between atomic-level theoretical modeling and reality by total scattering experiments. NANOSCALE 2015; 7:17902-17922. [PMID: 26463562 DOI: 10.1039/c5nr04678e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The extent to which current theoretical modeling alone can reveal real-world metallic nanoparticles (NPs) at the atomic level was scrutinized and demonstrated to be insufficient and how it can be improved by using a pragmatic approach involving straightforward experiments is shown. In particular, 4 to 6 nm in size silica supported Au(100-x)Pd(x) (x = 30, 46 and 58) explored for catalytic applications is characterized structurally by total scattering experiments including high-energy synchrotron X-ray diffraction (XRD) coupled to atomic pair distribution function (PDF) analysis. Atomic-level models for the NPs are built by molecular dynamics simulations based on the archetypal for current theoretical modeling Sutton-Chen (SC) method. Models are matched against independent experimental data and are demonstrated to be inaccurate unless their theoretical foundation, i.e. the SC method, is supplemented with basic yet crucial information on the length and strength of metal-to-metal bonds and, when necessary, structural disorder in the actual NPs studied. An atomic PDF-based approach for accessing such information and implementing it in theoretical modeling is put forward. For completeness, the approach is concisely demonstrated on 15 nm in size water-dispersed Au particles explored for bio-medical applications and 16 nm in size hexane-dispersed Fe48Pd52 particles explored for magnetic applications as well. It is argued that when "tuned up" against experiments relevant to metals and alloys confined to nanoscale dimensions, such as total scattering coupled to atomic PDF analysis, rather than by mere intuition and/or against data for the respective solids, atomic-level theoretical modeling can provide a sound understanding of the synthesis-structure-property relationships in real-world metallic NPs. Ultimately this can help advance nanoscience and technology a step closer to producing metallic NPs by rational design.
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Affiliation(s)
- Binay Prasai
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48858, USA.
| | - A R Wilson
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - B J Wiley
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Y Ren
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Valeri Petkov
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48858, USA.
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Cai F, Shan S, Yang L, Chen B, Luo J, Zhong CJ. CO oxidation on supported platinum group metal (PGM) based nanoalloys. Sci China Chem 2014. [DOI: 10.1007/s11426-014-5264-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shan S, Luo J, Yang L, Zhong CJ. Nanoalloy catalysts: structural and catalytic properties. Catal Sci Technol 2014. [DOI: 10.1039/c4cy00469h] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Shan S, Petkov V, Yang L, Luo J, Joseph P, Mayzel D, Prasai B, Wang L, Engelhard M, Zhong CJ. Atomic-Structural Synergy for Catalytic CO Oxidation over Palladium–Nickel Nanoalloys. J Am Chem Soc 2014; 136:7140-51. [DOI: 10.1021/ja5026744] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shiyao Shan
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Valeri Petkov
- Department
of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, United States
| | - Lefu Yang
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
- College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jin Luo
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Pharrah Joseph
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Dina Mayzel
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Binay Prasai
- Department
of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, United States
| | - Lingyan Wang
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Mark Engelhard
- EMSL, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Chuan-Jian Zhong
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
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Petkov V, Ren Y, Shan S, Luo J, Zhong CJ. A distinct atomic structure-catalytic activity relationship in 3-10 nm supported Au particles. NANOSCALE 2014; 6:532-538. [PMID: 24232747 DOI: 10.1039/c3nr05362h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bulk Au is very inert but Au nanoparticles less than 5 nm in size have been found to be catalytically active for several reactions, in particular for low-temperature oxidation of CO. Using high-energy X-ray diffraction coupled with atomic pair distribution function analysis and computer simulations we determine the structure of 3 nm and 10 nm Au particles supported on titania and silica as typical representatives of reducible and irreducible supports, respectively. We find that the synthesis protocol adopted in our work affects strongly and differently the structure of the Au nanoparticles on the different supports. This leads to clearly distinct dependences of the catalytic activity of the nanoparticles on their size. In the case of the silica support the catalytic activity of Au nanoparticles increases and in the case of the titania support it decreases with decreasing nanoparticle size. The experimental results are considered in terms of current theoretical predictions and found to be in good accord with them.
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Affiliation(s)
- Valeri Petkov
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, USA.
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Shan S, Petkov V, Yang L, Mott D, Wanjala BN, Cai F, Chen BH, Luo J, Zhong CJ. Oxophilicity and Structural Integrity in Maneuvering Surface Oxygenated Species on Nanoalloys for CO Oxidation. ACS Catal 2013. [DOI: 10.1021/cs400700r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shiyao Shan
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Valeri Petkov
- Department
of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, United States
| | - Lefu Yang
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
- College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Derrick Mott
- School
of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, 923-1292 Ishikawa, Japan
| | - Bridgid N. Wanjala
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Fan Cai
- College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Bing H. Chen
- College
of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jin Luo
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Chuan-Jian Zhong
- Department
of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
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Rao Peela N, Zheng W, Lee IC, Karim AM, Vlachos DG. Core-Shell Nanocatalyst Design by Combining High-Throughput Experiments and First-Principles Simulations. ChemCatChem 2013. [DOI: 10.1002/cctc.201300553] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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9
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Petkov V, Shan S, Chupas P, Yin J, Yang L, Luo J, Zhong CJ. Noble-transition metal nanoparticle breathing in a reactive gas atmosphere. NANOSCALE 2013; 5:7379-7387. [PMID: 23828235 DOI: 10.1039/c3nr02582a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In situ high-energy X-ray diffraction coupled to atomic pair distribution function analysis is used to obtain fundamental insight into the effect of the reactive gas environment on the atomic-scale structure of metallic particles less than 10 nm in size. To substantiate our recent discovery we investigate a wide range of noble-transition metal nanoparticles and confirm that they expand and contract radially when treated in oxidizing (O2) and reducing (H2) atmospheres, respectively. The results are confirmed by supplementary XAFS experiments. Using computer simulations guided by the experimental diffraction data we quantify the effect in terms of both relative lattice strain and absolute atomic displacements. In particular, we show that the effect leads to a small percent of extra surface strain corresponding to several tenths of Ångström displacements of the atoms at the outmost layer of the particles. The effect then gradually decays to zero within 4 atomic layers inside the particles. We also show that, reminiscent of a breathing type structural transformation, the effect is reproducible and reversible. We argue that because of its significance and widespread occurrence the effect should be taken into account in nanoparticle research.
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Affiliation(s)
- Valeri Petkov
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, USA.
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