Combined Schottky junction and doping effect in CdZnS@Au/BiVO Z-Scheme photocatalyst with boosted carriers charge separation for CO reduction by HO.

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, CdZnS@Au was in-situ deposited on the (010) facets of BiVO taking Au as a bridge for constructing a sandwich structure CdZnS@Au/BiVO Z-scheme photocatalyst. The electrons in BiVO (010) migrate unidirectionally to Au nanoparticles across the Schottky junction and effectively suppress opposite electrons flow, then be captured by the excited holes in CdZnS. Furthermore, Zn-doping also contributes to an appropriate redox ability and charge carriers separation. Benefiting from the dual-facilitated effects, the ternary CdZnS@Au/BiVO exhibited superior photocatalytic activity for CO reduction under visible light irradiation using HO as a reducing agent, as compared with CdS and CdS@Au/BiVO. Furthermore, the intermediate product HCOO* fixed on the surface of CdZnS@Au/BiVO is identified by in-situ FT-IR, playing a key role in the conversion of CO to CO and then improve photocatalytic selectivity.