Cu₂S/BiVO₄ Heterostructure Photoanode\nwith Extended Wavelength Range for Efficient Water Splitting

Abstract

Chalcogenides\nare a promising class of light-absorbers as photoanodes\nfor photoelectrochemical water splitting. However, the oxidation and\nthe sluggish reaction kinetics at the surface during water oxidation\nlimit their applications in solar-driven water splitting. Here, we\ndemonstrate an intriguing photoanode consisting of three components\nby deposition of Cu₂S via a simple successive ionic layer\nadsorption and reaction method on the surface of BiVO₄ to\nform a well-defined heterojunction. To protect Cu₂S from\noxidation and accelerate the reaction kinetics, a thin layer of CoFe–OH\nhas been successfully integrated uniformly on the surface. The resulting\nCu₂S/BiVO₄ composite photoanode shows a wider\nlight absorption range beyond 500 nm than bare BiVO₄ due\nto the incorporation of Cu₂S. The resulting photoanode\nexhibits dramatically enhanced performance and stability for water\nsplitting, and the photocurrent increases to 3.07 mA/cm² at 1.23 V_RHE. This work endows chalcogenides with a promise\nas candidate catalysts for highly efficient and stable solar-driven\nreactions.