1
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Baskaran S, Jung J. Termolecular Eley–Rideal pathway for efficient
CO
oxidation on phosphorene‐supported single‐atom cobalt catalyst. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Sambath Baskaran
- Department of Chemistry University of Ulsan Nam‐gu, Ulsan Republic of Korea
| | - Jaehoon Jung
- Department of Chemistry University of Ulsan Nam‐gu, Ulsan Republic of Korea
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2
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Development of Fluorescence-yield Wavelength-dispersive Soft X-ray Absorption Spectroscopy for Real-time Observation of Surface Chemical Reaction. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2022. [DOI: 10.1380/ejssnt.2022-020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Luo LH, Huang SD, Shang C, Liu ZP. Resolving Activation Entropy of CO Oxidation under the Solid–Gas and Solid–Liquid Conditions from Machine Learning Simulation. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ling-Heng Luo
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Si-Da Huang
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Cheng Shang
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institution, Shanghai 200030, China
| | - Zhi-Pan Liu
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institution, Shanghai 200030, China
- Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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4
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Sun C, Huang S, Huang M, Zhang X, Xu S, Wang H, Chen Y, Shi XR. Single-metal-atom catalysts supported on graphdiyne catalyze CO oxidation. Dalton Trans 2021; 50:10867-10879. [PMID: 34297016 DOI: 10.1039/d1dt00934f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single-metal-atom catalysts supported on graphdiyne (GDY) exhibit great potential for catalyzing low temperature CO oxidation in solving the increasingly serious environmental problems caused by CO emissions due to the high catalytic activity, clear structure, uniform metal distribution and low cost. First principle calculations were employed to study CO oxidation activities of four M@GDY single-atom catalysts (M = Pt, Rh, Cu, and Ni). For each catalyst, five possible reaction mechanisms including bi-molecular and tri-molecular reactions were discussed. According to the calculated reaction barriers, the preferred reaction pathway is via the bi-molecular Langmuir-Hinshelwood (BLH) ((CO + O2)* → OCOO* → CO2 + O*) route to yield the first CO2 molecule with 0.55, 0.51, and 0.53 eV as the energy barriers of the rate-limiting steps of Pt@GDY, Rh@GDY, and Cu@GDY, respectively, whereas for Ni@GDY, it switches to the tri-molecular Eley-Rideal (TER1) ((2CO)* + O2→ OCOOCO* → 2CO2) mechanism with the reaction barrier of the rate-limiting step being 1.27 eV. Based on the energy difference in the initial states of the five reaction mechanisms, TER1 is generally viable. No matter it is based on the calculated reaction barrier or the energy of the initial state of each mechanism, the non-noble Cu@GDY is supposed to be an efficient catalyst as the noble ones. The electronic properties are calculated to explain the bonding strength and origin of the catalytic performance. The GDY support plays an important role in the electron transfer process.
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Affiliation(s)
- Chunyan Sun
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
| | - Simin Huang
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
| | - Mengru Huang
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
| | - Xiangrui Zhang
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
| | - Shusheng Xu
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
| | - Hui Wang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P.R. China and University of the Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Yanyan Chen
- University of the Chinese Academy of Sciences, Beijing 100049, P.R. China and State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, P.R. China
| | - Xue-Rong Shi
- School of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620, P.R. China.
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5
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Tang Y, Chen W, Wu B, Zhao G, Liu Z, Li Y, Dai X. Formation Mechanism, Geometric Stability and Catalytic Activity of a Single Iron Atom Supported on N‐Doped Graphene. Chemphyschem 2019; 20:2506-2517. [DOI: 10.1002/cphc.201900666] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Yanan Tang
- Quantum Materials Research Center College of physics and Electronic Engineering Zhengzhou Normal University Zhengzhou 450044 China
| | - Weiguang Chen
- Quantum Materials Research Center College of physics and Electronic Engineering Zhengzhou Normal University Zhengzhou 450044 China
| | - Bingjie Wu
- Quantum Materials Research Center College of physics and Electronic Engineering Zhengzhou Normal University Zhengzhou 450044 China
| | - Gao Zhao
- Quantum Materials Research Center College of physics and Electronic Engineering Zhengzhou Normal University Zhengzhou 450044 China
| | - Zhiyong Liu
- College of Physics and Materials Science Henan Normal University Xinxiang Henan 453007 China
| | - Yi Li
- College of Physics and Materials Science Henan Normal University Xinxiang Henan 453007 China
| | - Xianqi Dai
- Quantum Materials Research Center College of physics and Electronic Engineering Zhengzhou Normal University Zhengzhou 450044 China
- College of Physics and Materials Science Henan Normal University Xinxiang Henan 453007 China
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6
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Tang Y, Chen W, Shen Z, Li C, Ma D, Dai X. A computational study of CO oxidation reactions on metal impurities in graphene divacancies. Phys Chem Chem Phys 2018; 20:2284-2295. [DOI: 10.1039/c7cp07397f] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on the density functional theory calculations, the formation geometry, electronic properties, and catalytic activity of metal impurities in divacancy graphene (M-DG, M = Mo, Fe, Co, and Ni) were systematically investigated.
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Affiliation(s)
- Yanan Tang
- Quantum materials research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Weiguang Chen
- Quantum materials research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Zigang Shen
- Quantum materials research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Chenggang Li
- Quantum materials research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Dongwei Ma
- School of Physics
- Anyang Normal University
- Anyang
- China
| | - Xianqi Dai
- Quantum materials research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
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7
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Ali S, Fu Liu T, Lian Z, Li B, Sheng Su D. The effect of defects on the catalytic activity of single Au atom supported carbon nanotubes and reaction mechanism for CO oxidation. Phys Chem Chem Phys 2017; 19:22344-22354. [DOI: 10.1039/c7cp03793g] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of CO oxidation by O2 on a single Au atom supported on pristine, mono atom vacancy (m), di atom vacancy (di) and the Stone Wales defect (SW) on single walled carbon nanotube (SWCNT) surface is systematically investigated theoretically using density functional theory.
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Affiliation(s)
- Sajjad Ali
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Tian Fu Liu
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Zan Lian
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Bo Li
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Dang Sheng Su
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
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8
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Liu Z, He T, Liu K, Chen W, Tang Y. Structural, electronic and catalytic performances of single-atom Fe stabilized by divacancy-nitrogen-doped graphene. RSC Adv 2017. [DOI: 10.1039/c6ra28387j] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The geometric, electronic and catalytic properties of a single-atom Fe embedded GN4 sheet (Fe–GN4) were systematically studied using first-principles calculations.
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Affiliation(s)
- Zhiyong Liu
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang
- China
| | - Tingwei He
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang
- China
| | - Kaikai Liu
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang
- China
| | - Weiguang Chen
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Yanan Tang
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang
- China
- Quantum Materials Research Center
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9
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Lu Z, Lv P, Yang Z, Li S, Ma D, Wu R. A promising single atom catalyst for CO oxidation: Ag on boron vacancies of h-BN sheets. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp02430d] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Due to “CO-Promoted O2 Activation”, the termolecular Eley–Rideal (TER) mechanism is the most relevant one for CO oxidation over the SAC, Ag1/BN.
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Affiliation(s)
- Zhansheng Lu
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
- Department of Physics and Astronomy
| | - Peng Lv
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Zongxian Yang
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
- Collaborative Innovation Center of Nano Functional Materials and Applications
| | - Shuo Li
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Dongwei Ma
- School of Physics
- Anyang Normal University
- Anyang 455000
- China
| | - Ruqian Wu
- Department of Physics and Astronomy
- University of California
- Irvine
- USA
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10
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Wang N, Tian Y, Zhao J, Jin P. CO oxidation catalyzed by silicon carbide (SiC) monolayer: A theoretical study. J Mol Graph Model 2016; 66:196-200. [PMID: 27135172 DOI: 10.1016/j.jmgm.2016.04.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/24/2016] [Accepted: 04/25/2016] [Indexed: 11/30/2022]
Abstract
Developing metal-free catalysts for CO oxidation has been a key scientific issue in solving the growing environmental problems caused by CO emission. In this work, the potential of the silicon carbide (SiC) monolayer as a metal-free catalyst for CO oxidation was systematically explored by means of density functional theory (DFT) computations. Our results revealed that CO oxidation reaction can easily proceed on SiC nanosheet, and a three-step mechanism was proposed: (1) the coadsorption of CO and O2 molecules, followed by (2) the formation of the first CO2 molecule, and (3) the recovery of catalyst by a second CO molecule. The last step is the rate-determining one of the whole catalytic reaction with the highest barrier of 0.65eV. Remarkably, larger curvature is found to have a negative effect on the catalytic performance of SiC nanosheet for CO oxidation. Therefore, our results suggested that flat SiC monolayer is a promising metal-free catalyst for CO oxidation.
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Affiliation(s)
- Nan Wang
- Chemistry and Chemical Engineering College, Harbin Normal University, Harbin, 150025,PR China
| | - Yu Tian
- Chemistry and Chemical Engineering College, Harbin Normal University, Harbin, 150025,PR China
| | - Jingxiang Zhao
- Chemistry and Chemical Engineering College, Harbin Normal University, Harbin, 150025,PR China.
| | - Peng Jin
- Key Laboratory of Micro- and Nano-scale Boron Nitride Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjian, 300130, PR China.
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11
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Kondoh H, Toyoshima R, Monya Y, Yoshida M, Mase K, Amemiya K, Mun BS. In situ analysis of catalytically active Pd surfaces for CO oxidation with near ambient pressure XPS. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Tang Y, Zhou J, Shen Z, Chen W, Li C, Dai X. High catalytic activity for CO oxidation on single Fe atom stabilized in graphene vacancies. RSC Adv 2016. [DOI: 10.1039/c6ra14476d] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The geometric, electronic and catalytic characters of Fe atom embedded graphene (including monovacancy and divacancy) are investigated using the first-principles method, which gives a reference on designing graphene-based catalysts for CO oxidation.
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Affiliation(s)
- Yanan Tang
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Jincheng Zhou
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Zigang Shen
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Weiguang Chen
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Chenggang Li
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
| | - Xianqi Dai
- Quantum Materials Research Center
- College of Physics and Electronic Engineering
- Zhengzhou Normal University
- Zhengzhou 450044
- China
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13
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Yoshida M, Kondoh H. In Situ Observation of Model Catalysts under Reaction Conditions Using X-ray Core-Level Spectroscopy. CHEM REC 2014; 14:806-18. [DOI: 10.1002/tcr.201402025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Masaaki Yoshida
- Department of Chemistry; Keio University; 3-14-1 Hiyoshi Yokohama 223-8522 Japan
| | - Hiroshi Kondoh
- Department of Chemistry; Keio University; 3-14-1 Hiyoshi Yokohama 223-8522 Japan
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14
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Deng Q, Zhao L, Gao X, Zhang M, Luo Y, Zhao Y. Single layer of polymeric cobalt phthalocyanine: promising low-cost and high-activity nanocatalysts for CO oxidation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:3506-13. [PMID: 23585395 DOI: 10.1002/smll.201300652] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 05/26/2023]
Abstract
The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically by using first-principles calculations. The results indicate that CoPc exhibits the highest catalytic activity for CO oxidation at room temperature with low energy barriers. By exploring the two well-established mechanisms for CO oxidation with O2 , namely, the Langmuir-Hinshelwood (LH) and the Eley-Rideal (ER) mechanisms, it is found that the first step of CO oxidation catalyzed by CoPc is the LH mechanism (CO + O2 → CO2 + O) with energy barrier as low as 0.65 eV. The second step proceeds via both ER and LH mechanisms (CO + O → CO2 ) with small energy barriers of 0.10 and 0.12 eV, respectively. The electronic resonance among Co-3d, CO-2π*, and O2 -2π* orbitals is responsible for the high activity of CoPc. These results have significant implications for a novel avenue to fabricate organometallic sheet nanocatalysts for CO oxidation with low cost and high activity.
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Affiliation(s)
- Qingming Deng
- Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
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15
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Zhao JX, Chen Y, Fu HG. Si-embedded graphene: an efficient and metal-free catalyst for CO oxidation by N2O or O2. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1242-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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17
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LIANG M, WANG X, LIU H, LIU H, WANG Y. Excellent catalytic properties over nanocomposite catalysts for selective hydrogenation of halonitrobenzenes. J Catal 2008. [DOI: 10.1016/j.jcat.2008.02.025] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Urakawa A, Bürgi T, Schläpfer HP, Baiker A. Simultaneous in situ monitoring of surface and gas species and surface properties by modulation excitation polarization-modulation infrared reflection-absorption spectroscopy: CO oxidation over Pt film. J Chem Phys 2006; 124:054717. [PMID: 16468911 DOI: 10.1063/1.2159484] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A method for in situ monitoring of surface and gas species utilizing separately the difference and sum reflectivity of two polarizations, normal and parallel to the surface, measured by polarization-modulation infrared reflection-absorption spectroscopy is presented. Surface and gas-phase spectra were separately but simultaneously obtained from the reflectivities. The technique is combined with modulation excitation spectroscopy to further enhance the sensitivity, and a small-volume cell was designed for this purpose. CO oxidation over a 40 nm Pt film on aluminum was investigated under moderate pressure (atmospheric pressure, 5% CO, and 5%-40% O2) at 373-433 K. The surface species involved in the oxidation process and the gas-phase species, both reactant (CO) and product (CO2), could be simultaneously monitored and analyzed quantitatively. In addition, the reflectivity change of the sample during the reaction was assigned to a near-surface bulk property change, that is, surface reconstruction to the oxide phase. Under an O2-rich atmosphere, two reactive phases, denoted as low- and high-activity phases, were identified. A large amount of atop CO was observed during the low-activity phase, while the adsorbed CO completely disappeared during the high-activity phase. The presence of an infrared-inactive CO2 precursor formed by the reaction between surface oxide and gaseous CO during the high-activity phase was inferred. The desorption of the CO2 precursor is facilitated under a CO-rich atmosphere, most likely, by surface reconstruction to metallic Pt and a competitive adsorption of CO on the surface.
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Affiliation(s)
- Atsushi Urakawa
- Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zürich, Switzerland
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19
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Gerrard AL, Weaver JF. Kinetics of CO oxidation on high-concentration phases of atomic oxygen on Pt(111). J Chem Phys 2005; 123:224703. [PMID: 16375491 DOI: 10.1063/1.2126667] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Temperature-programmed reaction spectroscopy (TPRS) and direct, isothermal reaction-rate measurements were employed to investigate the oxidation of CO on Pt(111) covered with high concentrations of atomic oxygen. The TPRS results show that oxygen atoms chemisorbed on Pt(111) at coverages just above 0.25 ML (monolayers) are reactive toward coadsorbed CO, producing CO(2) at about 295 K. The uptake of CO on Pt(111) is found to decrease with increasing oxygen coverage beyond 0.25 ML and becomes immeasurable at a surface temperature of 100 K when Pt(111) is partially covered with Pt oxide domains at oxygen coverages above 1.5 ML. The rate of CO oxidation measured as a function of CO beam exposure to the surface exhibits a nearly linear increase toward a maximum for initial oxygen coverages between 0.25 and 0.50 ML and constant surface temperatures between 300 and 500 K. At a fixed CO incident flux, the time required to reach the maximum reaction rate increases as the initial oxygen coverage is increased to 0.50 ML. A time lag prior to the reaction-rate maximum is also observed when Pt oxide domains are present on the surface, but the reaction rate increases more slowly with CO exposure and much longer time lags are observed, indicating that the oxide phase is less reactive toward CO than are chemisorbed oxygen atoms on Pt(111). On the partially oxidized surface, the CO exposure needed to reach the rate maximum increases significantly with increases in both the initial oxygen coverage and the surface temperature. A kinetic model is developed that reproduces the qualitative dependence of the CO oxidation rate on the atomic oxygen coverage and the surface temperature. The model assumes that CO chemisorption and reaction occur only on regions of the surface covered by chemisorbed oxygen atoms and describes the CO chemisorption probability as a decreasing function of the atomic oxygen coverage in the chemisorbed phase. The model also takes into account the migration of oxygen atoms from oxide domains to domains with chemisorbed oxygen atoms. According to the model, the reaction rate initially increases with the CO exposure because the rate of CO chemisorption is enhanced as the coverage of chemisorbed oxygen atoms decreases during reaction. Longer rate delays are predicted for the partially oxidized surface because oxygen migration from the oxide phase maintains high oxygen coverages in the coexisting chemisorbed oxygen phase that hinder CO chemisorption. It is shown that the time evolution of the CO oxidation rate is determined by the relative rates of CO chemisorption and oxygen migration, R(ad) and R(m), respectively, with an increase in the relative rate of oxygen migration acting to inhibit the reaction. We find that the time lag in the reaction rate increases nearly exponentially with the initial oxygen coverage [O](i) (tot) when [O](i) (tot) exceeds a critical value, which is defined as the coverage above which R(ad)R(m) is less than unity at fixed CO incident flux and surface temperature. These results demonstrate that the kinetics for CO oxidation on oxidized Pt(111) is governed by the sensitivity of CO binding and chemisorption on the atomic oxygen coverage and the distribution of surface oxygen phases.
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Affiliation(s)
- Alex L Gerrard
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
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Nakai I, Kondoh H, Amemiya K, Nagasaka M, Shimada T, Yokota R, Nambu A, Ohta T. Mechanism of the CO oxidation reaction on O-precovered Pt(111) surfaces studied with near-edge x-ray absorption fine structure spectroscopy. J Chem Phys 2005; 122:134709. [PMID: 15847491 DOI: 10.1063/1.1869415] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of island-periphery oxygen atoms after the CO saturation. CO coadsorption plays a role to induce the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. These mechanisms were confirmed by kinetic Monte Carlo simulations. The effect of coadsorbed water in the reaction mechanism was also examined.
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Affiliation(s)
- I Nakai
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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21
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Nagasaka M, Kondoh H, Nakai I, Ohta T. Oxygen island formation on Pt(111) studied by dynamic Monte Carlo simulation. J Chem Phys 2005; 122:44715. [PMID: 15740291 DOI: 10.1063/1.1835270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The formation of oxygen islands on the Pt(111) surface has been studied as a function of temperature by low energy electron diffraction (LEED) experiments and dynamic Monte Carlo (DMC) simulations. By raising the temperature, the (2 x 2) LEED spot intensity increases gradually and decays after a peak at around 255 K (T(p)) with full width of half maximum of 160 K. This behavior is interpreted by DMC simulations with the kinematical LEED analysis. In the DMC simulation, an oxygen atom hops to the neighboring site via the activation barrier of the saddle point. The potential energies at initial, saddle, and final points are changed at each hopping event depending on the surrounding oxygen atoms. By comparing the observed T(p) with the simulated one, the interaction energy E of oxygen atoms on Pt(111) was determined to be 25+/-3 meV at 2a(0). The DMC simulations visualize how the oxygen islands are formed and collapse on Pt(111) with increase of the temperature and well reproduce the surface configurations observed by scanning tunneling microscopy.
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Affiliation(s)
- Masanari Nagasaka
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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