Enhanced selective photocatalytic CO₂ reduction into CO over Ag/CdS nanocomposites under visible light

Highlights: • Ag/CdS nanocomposites were prepared by a facile photodeposition method. • Ag/CdS was more effective as a photocatalyst for CO₂ reduction than CdS. • Ag as cocatalyst served as electron trap as well as active site for CO₂ reduction reaction. - Abstract: Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO₂ reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO₂-to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO₂ reduction, which is probably responsible for the enhanced activity and selectivity of CO₂ to CO over Ag/CdS. The possible mechanism of CO₂ photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.