Platinum and indium sulfide-modified Cu3BiS3 photocathode for photoelectrochemical hydrogen evolutionElectronic supplementary information (ESI) available. See DOI: 10.1039/c7ta02740k

A polycrystalline Cu 3 BiS 3 film as a photoelectrode was fabricated by an electrodeposition method on a molybdenum-coated glass substrate for photoelectrochemical hydrogen evolution. The Cu 3 BiS 3 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 Cu 3 BiS 3 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 In 2 S 3 buffer layer, by which effective contact between p-type Cu 3 BiS 3 and n-type In 2 S 3 was formed, resulted in a significant increase in the photocurrent and a large shift of the photocurrent onset to the positive region. H 2 evolution under AM 1.5G simulated solar light was demonstrated using the Pt-In 2 S 3 /Cu 3 BiS 3 electrode combined with a Pt electrode under an applied bias (0 V vs. RHE). Platinum-deposited In 2 S 3 /Cu 3 BiS 3 film as a photoelectrode was fabricated on a molybdenum-coated glass substrate for photoelectrochemical hydrogen evolution.