New insight into mechanisms in water-gas-shift reaction on Au/CeO2(111): A density functional theory and kinetic study

Y. Chen, H.F. Wang, R. Burch, Christopher Hardacre, P. Hu

Research output: Contribution to journalArticle

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Abstract

Using density functional theory (DFT) and kinetic analyses, a new carboxyl mechanism for the water-gas-shift reaction (WGSR) on Au/CeO2(111) is proposed. Many elementary steps in the WGSR are studied using an Au cluster supported on CeO2(111). It is found that (i) water can readily dissociate at the interface between Au and CeO2; (ii) CO2 can be produced via two steps: adsorbed CO on the Au cluster reacts with active OH on ceria to form the carboxyl (COOH) species and then COOH reacts with OH to release CO2; and (iii) two adsorbed H atoms recombine to form molecular H-2 on the Au cluster. Our kinetic analyses show that the turnover frequency of the carboxyl mechanism is consistent with the experimental one while the rates of redox and formate mechanisms are much slower than that of carboxyl mechanism. It is suggested that the carboxyl pathway is likely to be responsible for WGSR on Au/CeO2.
Original languageEnglish
Pages (from-to)121-133
Number of pages13
JournalFaraday Discussions
Volume152
DOIs
Publication statusPublished - 2011

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Water gas shift
Density functional theory
formic acid
density functional theory
Kinetics
shift
kinetics
gases
water
Cerium compounds
Carbon Monoxide
formates
Atoms
Water
atoms

Cite this

Chen, Y. ; Wang, H.F. ; Burch, R. ; Hardacre, Christopher ; Hu, P. / New insight into mechanisms in water-gas-shift reaction on Au/CeO2(111): A density functional theory and kinetic study. In: Faraday Discussions. 2011 ; Vol. 152. pp. 121-133.
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abstract = "Using density functional theory (DFT) and kinetic analyses, a new carboxyl mechanism for the water-gas-shift reaction (WGSR) on Au/CeO2(111) is proposed. Many elementary steps in the WGSR are studied using an Au cluster supported on CeO2(111). It is found that (i) water can readily dissociate at the interface between Au and CeO2; (ii) CO2 can be produced via two steps: adsorbed CO on the Au cluster reacts with active OH on ceria to form the carboxyl (COOH) species and then COOH reacts with OH to release CO2; and (iii) two adsorbed H atoms recombine to form molecular H-2 on the Au cluster. Our kinetic analyses show that the turnover frequency of the carboxyl mechanism is consistent with the experimental one while the rates of redox and formate mechanisms are much slower than that of carboxyl mechanism. It is suggested that the carboxyl pathway is likely to be responsible for WGSR on Au/CeO2.",
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New insight into mechanisms in water-gas-shift reaction on Au/CeO2(111): A density functional theory and kinetic study. / Chen, Y.; Wang, H.F.; Burch, R.; Hardacre, Christopher; Hu, P.

In: Faraday Discussions, Vol. 152, 2011, p. 121-133.

Research output: Contribution to journalArticle

TY - JOUR

T1 - New insight into mechanisms in water-gas-shift reaction on Au/CeO2(111): A density functional theory and kinetic study

AU - Chen, Y.

AU - Wang, H.F.

AU - Burch, R.

AU - Hardacre, Christopher

AU - Hu, P.

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N2 - Using density functional theory (DFT) and kinetic analyses, a new carboxyl mechanism for the water-gas-shift reaction (WGSR) on Au/CeO2(111) is proposed. Many elementary steps in the WGSR are studied using an Au cluster supported on CeO2(111). It is found that (i) water can readily dissociate at the interface between Au and CeO2; (ii) CO2 can be produced via two steps: adsorbed CO on the Au cluster reacts with active OH on ceria to form the carboxyl (COOH) species and then COOH reacts with OH to release CO2; and (iii) two adsorbed H atoms recombine to form molecular H-2 on the Au cluster. Our kinetic analyses show that the turnover frequency of the carboxyl mechanism is consistent with the experimental one while the rates of redox and formate mechanisms are much slower than that of carboxyl mechanism. It is suggested that the carboxyl pathway is likely to be responsible for WGSR on Au/CeO2.

AB - Using density functional theory (DFT) and kinetic analyses, a new carboxyl mechanism for the water-gas-shift reaction (WGSR) on Au/CeO2(111) is proposed. Many elementary steps in the WGSR are studied using an Au cluster supported on CeO2(111). It is found that (i) water can readily dissociate at the interface between Au and CeO2; (ii) CO2 can be produced via two steps: adsorbed CO on the Au cluster reacts with active OH on ceria to form the carboxyl (COOH) species and then COOH reacts with OH to release CO2; and (iii) two adsorbed H atoms recombine to form molecular H-2 on the Au cluster. Our kinetic analyses show that the turnover frequency of the carboxyl mechanism is consistent with the experimental one while the rates of redox and formate mechanisms are much slower than that of carboxyl mechanism. It is suggested that the carboxyl pathway is likely to be responsible for WGSR on Au/CeO2.

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