Enhanced Photoelectrochemical Performance of the BiVO4/Zn:BiVO4 Homojunction for Water Oxidation

Abstract

AbstractBismuth vanadate is a promising semiconductor for photoelectrochemical (PEC) water oxidation under visible light. Yet its PEC performance is limited by its poor electron‐transfer mobility. In this study we modified the BiVO4 surface with Zn to address this problem. We used a ZnO coating and etching treatment to dope Zn atoms at the surface of BiVO4 by replacing the Bi atoms. The surface Zn doping treatment lowered the Fermi level of the outer part of BiVO4 (surface) and formed a BiVO4/Zn:BiVO4 homojunction with a type II band alignment with the inner part of BiVO4 (bulk). With this homojunction, the charge transfer process across the depletion region of the BiVO4 electrode was improved and the surface trapping of photogenerated electrons was avoided, which led to an enhanced PEC performance.