Issue 22, 2008

CO Preferential oxidation promoted by UV irradiation in the presence of H2 over Au/TiO2

Abstract

The catalytic oxidation of CO was performed over Au/TiO2 under UV irradiation in the presence of H2 in different reaction systems. It was found that the introduction of H2 enhanced the CO thermocatalytic oxidation in a CO pre-introduced system (CO/O2vs. CO/H2/O2), but suppressed that in an O2 pre-introduced (O2/CO vs. O2/H2/CO) system. Although the CO oxidation in both CO/H2/O2 and O2/H2/CO systems could be remarkably enhanced under UV irradiation, the oxidation of H2 was suppressed under UV irradiation. It was proposed that the dissociative chemisorption H ([triple bond, length as m-dash]Ti–H) at surface oxygen vacancy sites of TiO2 could act as both the electron-acceptors for the photogeneration electrons and the electron-donors for the chemisorbed O2 at TiO2, and thus enhance the CO oxidation during the coinstantaneous process of thermocatalysis and photocatalysis. The suppression of H2 thermocatalytic oxidation under UV irradiation might be ascribed to the electron transfer effect, i.e., the dissociative chemisorption H on Au (Au–H) could be desorbed at the H2 molecule via accepting the photogenerated electrons from TiO2.

Graphical abstract: CO Preferential oxidation promoted by UV irradiation in the presence of H2 over Au/TiO2

Supplementary files

Article information

Article type
Paper
Submitted
30 Nov 2007
Accepted
04 Mar 2008
First published
20 Mar 2008

Phys. Chem. Chem. Phys., 2008,10, 3256-3262

CO Preferential oxidation promoted by UV irradiation in the presence of H2 over Au/TiO2

W. Dai, X. Chen, X. Wang, P. Liu, D. Li, G. Li and X. Fu, Phys. Chem. Chem. Phys., 2008, 10, 3256 DOI: 10.1039/B718541C

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