Photoelectrochemical reduction of aqueous protons with a CuO|CuBi2O4 heterojunction under visible light irradiation

Abstract

A p-type heterojunction photoelectrode consisting of platinized CuBi₂O₄ layered on a CuO film was prepared. The CuO|CuBi₂O₄|Pt electrode photo-generates H₂ in pH neutral aqueous solution during visible light irradiation and exhibits a substantially enhanced photocurrent compared to CuO|Pt and CuBi₂O₄|Pt electrodes. Reduced electron–hole recombination by the band offsets in the heterostructure is responsible for the improved photoelectrochemical performance of CuO|CuBi₂O₄ with a small band-gap of approximately 1.5 eV.