Platinum and indium sulfide-modified Cu3BiS3 photocathode for photoelectrochemical hydrogen evolution

Abstract

A polycrystalline Cu₃BiS₃ film as a photoelectrode was fabricated by an electrodeposition method on a molybdenum-coated glass substrate for photoelectrochemical hydrogen evolution. The Cu₃BiS₃ film was composed of dense crystallites with thicknesses of ca. 0.65 μm, and the optical bandgap was estimated to be ca. 1.6 eV. Photoelectrochemical characterization revealed that the Cu₃BiS₃ film was a p-type semiconductor with a flat band potential of ca. +0.1 V (vs. Ag/AgCl at pH 6), which is suitable for water reduction but cannot be used for water oxidation. Deposition of an In₂S₃ buffer layer, by which effective contact between p-type Cu₃BiS₃ and n-type In₂S₃ was formed, resulted in a significant increase in the photocurrent and a large shift of the photocurrent onset to the positive region. H₂ evolution under AM 1.5G simulated solar light was demonstrated using the Pt–In₂S₃/Cu₃BiS₃ electrode combined with a Pt electrode under an applied bias (0 V vs. RHE).