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Carbon induced segregation of Ni atoms in Cu-Ni alloy. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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2
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Hydrogenation of Furfural to Furfuryl Alcohol over Ru Particles Supported on Mildly Oxidized Biochar. Catalysts 2020. [DOI: 10.3390/catal10080934] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Catalytic hydrogenation of aldehydes is required as the stabilizing step in bio-oils conversion. Ruthenium supported on carbon was used in the present work for hydrogenation of furfural (FF) to furfuryl alcohol (FA). Converting a biochar with no surface area and low carboxyl groups surface density to an outstanding catalyst support using a very simple mild air/steam oxidation is the original contribution of this work. The mildly oxidized biochar is impregnated with a targeted loading of 2.5 wt.% Ru via ion-exchange, using Ru(NH3)6Cl2 precursor. ICP analysis shows that the mild oxidation increases Ru adsorption capacity of untreated biochar from 1.2 to 2.2 wt.%. H2 chemisorption and TEM analysis indicate that the preliminary mild oxidation leads to higher Ru dispersion. XPS analysis also shows that the treatment prevents Ru from surface segregation. The highest value of 93% FA selectivity at 53% FF conversion was obtained in a batch autoclave reactor under optimized conditions.
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Kwon T, Jun M, Lee K. Catalytic Nanoframes and Beyond. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2001345. [PMID: 32633878 DOI: 10.1002/adma.202001345] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/01/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
The ever-increasing need for the production and expenditure of sustainable energy is a result of the astonishing rate of consumption of fossil fuels and the accompanying environmental problems. Emphasis is being directed to the generation of sustainable energy by the fuel cell and water splitting technologies. Accordingly, the development of highly efficient electrocatalysts has attracted significant interest, as the fuel cell and water splitting technologies are critically dependent on their performance. Among numerous catalyst designs under investigation, nanoframe catalysts have an intrinsically large surface area per volume and a tunable composition, which impacts the number of catalytically active sites and their intrinsic catalytic activity, respectively. Nevertheless, the structural integrity of the nanoframe during electrochemical operation is an ongoing concern. Some significant advances in the field of nanoframe catalysts have been recently accomplished, specifically geared to resolving the catalytic stability concerns and significantly boosting the intrinsic catalytic activity of the active sites. Herein, general synthetic concepts of nanoframe structures and their structure-dependent catalytic performance are summarized, along with recent notable advances in this field. A discussion on the remaining challenges and future directions, addressing the limitations of nanoframe catalysts, are also provided.
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Affiliation(s)
- Taehyun Kwon
- Department of Chemistry and Research Institute for Natural Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Minki Jun
- Department of Chemistry and Research Institute for Natural Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Kwangyeol Lee
- Department of Chemistry and Research Institute for Natural Sciences, Korea University, Seoul, 02841, Republic of Korea
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Zhao Q, Wang C, Wang H, Wang J, Tang Y, Mao Z, Sasaki K. Synthesis of a high-performance low-platinum PtAg/C alloyed oxygen reduction catalyst through the gradual reduction method. NEW J CHEM 2020. [DOI: 10.1039/c9nj06156h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A low-platinum PtAg/C catalyst with excellent ORR activity and durability in acid is demonstrated to be promising for ORR catalysis.
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Affiliation(s)
- Qing Zhao
- Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology
- INET
- Tsinghua University
- Beijing
- P. R. China
| | - Cheng Wang
- Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology
- INET
- Tsinghua University
- Beijing
- P. R. China
| | | | - Jianlong Wang
- Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology
- INET
- Tsinghua University
- Beijing
- P. R. China
| | - Yaping Tang
- Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology
- INET
- Tsinghua University
- Beijing
- P. R. China
| | - Zongqiang Mao
- Zhang Jiagang Joint Institute for Hydrogen Energy and Lithium-Ion Battery Technology
- INET
- Tsinghua University
- Beijing
- P. R. China
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van Muyden AP, Siankevich S, Yan N, Dyson PJ. Discovery of a Highly Active Catalyst for Hydrogenolysis of C−O Bonds via Systematic, Multi‐metallic Catalyst Screening. ChemCatChem 2019. [DOI: 10.1002/cctc.201900462] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Antoine P. van Muyden
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Sviatlana Siankevich
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Ning Yan
- Faculty of EngineeringUniversity of Singapore (NUS) 21 Lower Kent Ridge Road 119077 Singapore
| | - Paul J. Dyson
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
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6
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Radlik M, Śrębowata A, Juszczyk W, Matus K, Małolepszy A, Karpiński Z. n-Hexane conversion on γ-alumina supported palladium–platinum catalysts. ADSORPTION 2019. [DOI: 10.1007/s10450-019-00083-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Qi W, Huang Z, Chen Z, Fu L, Zhang Z. Experimental and theoretical investigation of oxidative methane activation on Pd–Pt catalysts. RSC Adv 2019; 9:11385-11395. [PMID: 35520245 PMCID: PMC9063388 DOI: 10.1039/c9ra00735k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/23/2019] [Indexed: 11/30/2022] Open
Abstract
Density functional theory (DFT) and measurements of rate are used to provide evidence for the rate determining step (RDS) and requirements of the active site for CH4 combustion on Pd–Pt bimetallic catalysts in five different distinct kinetic regimes. These five regimes exhibit different rate equations for methane combustion due to the reaction rate constants and diverse dominant adsorbed species for these different kinetically relevant steps. Oxygen chemical potential at the Pd–Pt surface was replaced by oxygen pressure, reflecting the kinetic coupling between C–H and O
Created by potrace 1.16, written by Peter Selinger 2001-2019
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O bond cleavage steps. C–H bond cleavage occurs on different active sites in five of these kinetic regimes, evolving from vacancy–vacancy (*–*) to oxygen–vacancy (O*–*), oxygen–oxygen (O*–O*) site pairs, monolayer Pd–O, and ultimately to oxide bulk with Pd–O site pairs as the oxygen chemical potential increases. It is easier to form a metallic surface at low oxygen pressure, implying minimal O* coverage. The sole kinetically relevant step on uncovered Pd–Pt surfaces for methane combustion is OO bond cleavage. The supply of oxygen is obviously more important than the supply of methane in regime (I). As vacancies become less available on metallic surfaces, C–H bond cleavage occurs via O*–* paired sites, the energy barrier of which is much higher than that on uncovered Pd–Pt surfaces. In this regime (II), OO bond cleavage is still an irreversible process because O* will be consumed by the rapidly formed products of methane dissociation. For the oxygen saturated surfaces in regime (III), C–H bond cleavage occurs on two adjacent adsorbed oxygens that form OH and weak CH3–O bond interactions, resulting in a low activity for methane combustion. On the oxidation surfaces (IV and V), exposed metal atoms and their adjacent exposed lattice oxygen were the active sites, leading to a large decrease in C–H bond cleavage energy barrier, deduced from both experiment and theory. The increase of the metallic oxide thickness (increase of oxygen potential) increases the methane combustion turnover rates on Pd–Pt catalysts. Density functional theory and measurements of rate are used to provide evidence for the rate determining step and requirements of the active site for CH4 combustion on Pd–Pt bimetallic catalysts in five different distinct kinetic regimes.![]()
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Affiliation(s)
- Wenjie Qi
- Key Laboratory of Advanced Manufacturing Technology for Automobile Parts
- Ministry of Education
- Chongqing University of Technology
- Chongqing 400050
- China
| | - Zehao Huang
- Key Laboratory of Advanced Manufacturing Technology for Automobile Parts
- Ministry of Education
- Chongqing University of Technology
- Chongqing 400050
- China
| | - Zheming Chen
- Key Laboratory of Advanced Manufacturing Technology for Automobile Parts
- Ministry of Education
- Chongqing University of Technology
- Chongqing 400050
- China
| | - Lijuan Fu
- Key Laboratory of Advanced Manufacturing Technology for Automobile Parts
- Ministry of Education
- Chongqing University of Technology
- Chongqing 400050
- China
| | - Zhigang Zhang
- Key Laboratory of Advanced Manufacturing Technology for Automobile Parts
- Ministry of Education
- Chongqing University of Technology
- Chongqing 400050
- China
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8
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Nassiri H, Hayes RE, Semagina N. Stability of Pd-Pt catalysts in low-temperature wet methane combustion: Metal ratio and particle reconstruction. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.04.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Fernandes VR, Bossche MVD, Knudsen J, Farstad MH, Gustafson J, Venvik HJ, Grönbeck H, Borg A. Reversed Hysteresis during CO Oxidation over Pd75Ag25(100). ACS Catal 2016. [DOI: 10.1021/acscatal.6b00658] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vasco R. Fernandes
- Department
of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Maxime Van den Bossche
- Competence
Centre for Catalysis and Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Jan Knudsen
- MAX
IV Laboratory, Lund University, Box 118, SE-221 00 Lund, Sweden
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Mari H. Farstad
- Department
of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Johan Gustafson
- Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
| | - Hilde J. Venvik
- Department
of Chemical Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Henrik Grönbeck
- Competence
Centre for Catalysis and Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Anne Borg
- Department
of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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12
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Qi W, Ran J, Wang R, Du X, Shi J, Niu J, Zhang P, Ran M. Kinetic consequences of methane combustion on Pd, Pt and Pd–Pt catalysts. RSC Adv 2016. [DOI: 10.1039/c6ra21150j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The kinetic consequences of methane combustion on PdxPt1−x oxide surfaces were investigated with kinetic data and density functional theory treatments.
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Affiliation(s)
- Wenjie Qi
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Jingyu Ran
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Ruirui Wang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Xuesen Du
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Jun Shi
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Juntian Niu
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Peng Zhang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems
- Ministry of Education of PRC
- Chongqing University
- Chongqing
- China
| | - Mingchu Ran
- College of Power Engineering
- Chongqing University
- Chongqing 400030
- China
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13
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Yu Y, Xiao W, Wang J, Wang L. First-Principles Study of Mo Segregation in MoNi(111): Effects of Chemisorbed Atomic Oxygen. MATERIALS (BASEL, SWITZERLAND) 2015; 9:E5. [PMID: 28787811 PMCID: PMC5456558 DOI: 10.3390/ma9010005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 12/05/2015] [Accepted: 12/17/2015] [Indexed: 11/17/2022]
Abstract
Segregation at metal alloy surfaces is an important issue because many electrochemical and catalytic properties are directly correlated to the surface composition. We have performed density functional theory calculations for Mo segregation in MoNi(111) in the presence of chemisorbed atomic oxygen. In particular, the coverage dependence and possible adsorption-induced segregation phenomena are addressed by investigating segregation energies of the Mo atom in MoNi(111). The theoretical calculated results show that the Mo atom prefers to be embedded in the bulk for the clean MoNi(111), while it segregates to the top-most layer when the oxygen coverage is thicker than 1/9 monolayer (ML). Furthermore, we analyze the densities of states for the clean and oxygen-chemisorbed MoNi(111), and see a strong covalent bonding between Mo d-band states and O p-states. The present study provides valuable insight for exploring practical applications of Ni-based alloys as hydrogen evolution electrodes.
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Affiliation(s)
- Yanlin Yu
- General Research Institute for Nonferrous Metals, Beijing 100088, China.
| | - Wei Xiao
- General Research Institute for Nonferrous Metals, Beijing 100088, China.
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Jianwei Wang
- General Research Institute for Nonferrous Metals, Beijing 100088, China.
| | - Ligen Wang
- General Research Institute for Nonferrous Metals, Beijing 100088, China.
- Power Environmental Energy Research Institute, Covina, CA 91722, USA.
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14
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Liao H, Fisher A, Xu ZJ. Surface Segregation in Bimetallic Nanoparticles: A Critical Issue in Electrocatalyst Engineering. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3221-46. [PMID: 25823964 DOI: 10.1002/smll.201403380] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 02/07/2015] [Indexed: 05/23/2023]
Abstract
Bimetallic nanoparticles are a class of important electrocatalyst. They exhibit a synergistic effect that critically depends on the surface composition, which determines the surface properties and the adsorption/desorption behavior of the reactants and intermediates during catalysis. The surface composition can be varied, as nanoparticles are exposed to certain environments through surface segregation. Thermodynamically, this is caused by a difference in surface energy between the two metals. It may lead to the enrichment of one metal on the surface and the other in the core. The external conditions that influence the surface energy may lead to the variation of the thermodynamic steady state of the particle surface and, thus, offer a chance to vary the surface composition. In this review, the most recent and important progress in surface segregation of bimetallic nanoparticles and its impact in electrocatalysis are introduced. Typical segregation inducements and surface characterization techniques are discussed in detail. It is concluded that surface segregation is a critical issue when designing bimetallic catalysts. It is necessary to explore methods to control it and utilize it as a way towards producing robust, bimetallic electrocatalysts.
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Affiliation(s)
- Hanbin Liao
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Energy Research Institute@NTU, ERI@NNanyang Technological University, Singapore
| | - Adrian Fisher
- Department of Chemical Engineering, Cambridge University, Cambridge, CB2 3RA, UK
| | - Zhichuan J Xu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Energy Research Institute@NTU, ERI@NNanyang Technological University, Singapore
- Solar Fuels Lab, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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15
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Jiang P, Bao X, Salmeron M. Catalytic reaction processes revealed by scanning probe microscopy. [corrected]. Acc Chem Res 2015; 48:1524-31. [PMID: 25856470 DOI: 10.1021/acs.accounts.5b00017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heterogeneous catalysis is of great importance for modern society. About 80% of the chemicals are produced by catalytic reactions. Green energy production and utilization as well as environmental protection also need efficient catalysts. Understanding the reaction mechanisms is crucial to improve the existing catalysts and develop new ones with better activity, selectivity, and stability. Three components are involved in one catalytic reaction: reactant, product, and catalyst. The catalytic reaction process consists of a series of elementary steps: adsorption, diffusion, reaction, and desorption. During reaction, the catalyst surface can change at the atomic level, with roughening, sintering, and segregation processes occurring dynamically in response to the reaction conditions. Therefore, it is imperative to obtain atomic-scale information for understanding catalytic reactions. Scanning probe microscopy (SPM) is a very appropriate tool for catalytic research at the atomic scale because of its unique atomic-resolution capability. A distinguishing feature of SPM, compared to other surface characterization techniques, such as X-ray photoelectron spectroscopy, is that there is no intrinsic limitation for SPM to work under realistic reaction conditions (usually high temperature and high pressure). Therefore, since it was introduced in 1981, scanning tunneling microscopy (STM) has been widely used to investigate the adsorption, diffusion, reaction, and desorption processes on solid catalyst surfaces at the atomic level. STM can also monitor dynamic changes of catalyst surfaces during reactions. These invaluable microscopic insights have not only deepened the understanding of catalytic processes, but also provided important guidance for the development of new catalysts. This Account will focus on elementary reaction processes revealed by SPM. First, we will demonstrate the power of SPM to investigate the adsorption and diffusion process of reactants on catalyst surfaces at the atomic level. Then the dynamic processes, including surface reconstruction, roughening, sintering, and phase separation, studied by SPM will be discussed. Furthermore, SPM provides valuable insights toward identifying the active sites and understanding the reaction mechanisms. We also illustrate here how both ultrahigh vacuum STM and high pressure STM provide valuable information, expanding the understanding provided by traditional surface science. We conclude with highlighting remarkable recent progress in noncontact atomic force microscopy (NC-AFM) and inelastic electron tunneling spectroscopy (IETS), and their impact on single-chemical-bond level characterization for catalytic reaction processes in the future.
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Affiliation(s)
- Peng Jiang
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xinhe Bao
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Miquel Salmeron
- Materials
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
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16
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Li T, Bagot P, Marquis E, Edman Tsang S, Smith G. Atomic engineering of platinum alloy surfaces. Ultramicroscopy 2013; 132:205-11. [DOI: 10.1016/j.ultramic.2012.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 10/19/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
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18
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Sabbe MK, Laín L, Reyniers MF, Marin GB. Benzene adsorption on binary Pt3M alloys and surface alloys: a DFT study. Phys Chem Chem Phys 2013; 15:12197-214. [DOI: 10.1039/c3cp50617g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Taufany F, Pan CJ, Lai FJ, Chou HL, Sarma LS, Rick J, Lin JM, Lee JF, Tang MT, Hwang BJ. Relating the Composition of PtxRu100−x/C Nanoparticles to Their Structural Aspects and Electrocatalytic Activities in the Methanol Oxidation Reaction. Chemistry 2012. [DOI: 10.1002/chem.201202473] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Bimetallic Pt–Pd/silica–alumina hydrotreating catalysts – Part I: Physicochemical characterization. J Catal 2012. [DOI: 10.1016/j.jcat.2012.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Duan Z, Wang G. Monte Carlo simulation of surface segregation phenomena in extended and nanoparticle surfaces of Pt-Pd alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:475301. [PMID: 22075765 DOI: 10.1088/0953-8984/23/47/475301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The surface segregation phenomena in the extended and nanoparticle surfaces of Pt-Pd alloys have been studied using the Monte Carlo (MC) simulation method and the modified embedded-atom method (MEAM) potentials developed for Pt-Pd alloys. The MEAM potentials were fitted to reproduce the experimental values of the lattice parameters, cohesive energies and surface energies of pure Pt and Pd metals, as well as the density functional theory calculation results of the lattice parameters and heat of formation of L1(2) Pt(3)Pd, L1(0) PtPd and L1(2) PtPd(3) crystal. Using the MC method and the developed MEAM potentials, we calculated the Pt concentrations in the outermost three layers of the equilibrium (111), (100) and (110) extended surfaces as well as the outermost surfaces of the equilibrium cubo-octahedral nanoparticles of Pt-Pd alloys. Our simulation results showed that the Pd atoms would segregate into the outermost layers of the extended surfaces and the Pt concentration would increase monotonically from the extended surfaces into the bulk. The equilibrium Pt-Pd nanoparticles were found to have Pd-enriched shells and Pt-enriched cores. In the shell of the Pt-Pd nanoparticles, the Pd atoms were predicted to preferably segregate to the (100) facets rather than the (111) facets.
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Affiliation(s)
- Zhiyao Duan
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
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22
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Ma Y, Balbuena PB. Kinetic Model of Surface Segregation in Pt-Based Alloys. J Chem Theory Comput 2008; 4:1991-5. [DOI: 10.1021/ct8004062] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yuguang Ma
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843
| | - Perla B. Balbuena
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843
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van de Grampel RD, Ming W, Gildenpfennig A, Laven J, Brongersma HH, de With G, van der Linde R. Quantification of fluorine density in the outermost atomic layer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:145-149. [PMID: 15745012 DOI: 10.1021/la0353071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The outermost atomic layer of perfluorinated thiol monolayers on gold and poly(tetrafluoroethylene) (PTFE) is analyzed by low-energy ion scattering. Absolute quantification of fluorine density in this layer was achieved after calibrating the fluorine signal with a freshly cleaved LiF(100) single crystal. The fluorine density of monolayers of a C8F17-thiol on gold was 1.48 x 10(15) F atoms/cm2, whereas for PTFE a value of 1.24 x 1015 F atoms/cm2 was observed. This difference was explained by the different tilt angles of the thiol on gold and PTFE chains with respect to the surface normal. Both a configurational and a molecular interpretation on the perfluorinated thiol monolayer on gold are given.
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Affiliation(s)
- R D van de Grampel
- Laboratory of Coatings Technology, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Noble Metal Segregation and Cluster Size of Pt/Rh/CeO2/γ-Al2O3 Automotive Three-Way Catalysts Studied with Low-Energy Ion Scattering. J Catal 2001. [DOI: 10.1006/jcat.2001.3391] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Cortenraad R, Denier van der Gon AW, Brongersma HH, Ermolov SN, Glebovsky VG. Quantification of the surface composition of low-work function surfaces using low-energy ion scattering. SURF INTERFACE ANAL 2001. [DOI: 10.1002/sia.972] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Non-steady activity during methane combustion over Pd/Al2O3 and the influences of Pt and CeO2 additives. Catal Today 1999. [DOI: 10.1016/s0920-5861(98)00308-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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