Combined Schottky junction and doping effect in CdxZn1-xS@Au/BiVO4 Z-Scheme photocatalyst with boosted carriers charge separation for CO2 reduction by H2O

Abstract A Z-scheme photosystems combining Schottky junction and loading of applicable bandgap semiconductor is beneficial for enhancing the charge carriers’ separation/transfer as well as maintain their excellent redox ability. Here, CdxZn1-xS@Au was in-situ deposited on the (0 1 0) facets of BiVO4 taking Au as a bridge for constructing a sandwich structure CdxZn1-xS@Au/BiVO4 Z-scheme photocatalyst. The electrons in BiVO4 (0 1 0) migrate unidirectionally to Au nanoparticles across the Schottky junction and effectively suppress opposite electrons flow, then be captured by the excited holes in CdxZn1-xS. Furthermore, Zn-doping also contributes to an appropriate redox ability and charge carriers separation. Benefiting from the dual-facilitated effects, the ternary CdxZn1-xS@Au/BiVO4 exhibited superior photocatalytic activity for CO2 reduction under visible light irradiation using H2O as a reducing agent, as compared with CdS and CdS@Au/BiVO4. Furthermore, the intermediate product HCOO* fixed on the surface of CdxZn1-xS@Au/BiVO4 is identified by in-situ FT-IR, playing a key role in the conversion of CO2 to CO and then improve photocatalytic selectivity.