The role of electron transfer behavior induced by CO chemisorption on visible-light-driven CO conversion over WO3 and CuWO4/WO3

Visible-light-driven CO conversion has attracted many research efforts. Herein we study the reaction mechanism from the perspective of electron transfer behavior during CO adsorption (CO (ad)). The WO3 and CuWO4/WO3 films were in-situ synthesized, and then were investigated their behaviors for adsorbing CO and catalyzing CO conversion under visible light via gas sensing system and in-situ DRIFTS testing, respectively. It was found that the CO (ad) at W5+-W5+ site will form bridge adsorbed CO species over WO3, and donate electrons to W5+, resulting in its light-driven oxidation by O-2. The CO (ad) at W-0 site forms linear and gem-dicarbonyl adsorbed CO species over CuWO4/WO3, and accept electrons from W-0, then its reduction by H-2. The result shows the light-driven CO oxidation or reduction on WO3 and CuWO4/WO3 would be somewhat dependent on the electron transfer behavior induced by different modes of CO chemisorption and the Fermi level of sample itself.