New insight into mechanisms in water-gas-shift reaction on Au/CeO 2(111): A density functional theory and kinetic study

Ying Chen, Haifeng Wang, Robbie Burch, Christopher Hardacre, P. Hu

    Research output: Contribution to journalArticlepeer-review

    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 H2 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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