Boosting the performance of delafossite photocathode through constructing a CuFeO2/CuO heterojunction for photoelectrochemical water reduction

CuFeO2 is a promising photocathode material with favorable band gap and chemical stability in alkaline electrolytes. However, CuFeO2 is suffered from poor photoinduced electron-hole separation and collection. In this paper, we utilize a heterojunction strategy for inhibiting charge recombination and enhancing its photoelectrochemical performance. CuFeO2/CuO heterojunction photocathodes were prepared by a facile spin coating method, which were used for photoelectrochemical water reduction. A high photocurrent as much as 50A/cm(2) after 600 s irradiation of white light at the potential of -0.5V versus Ag/AgCl electrode is observed, which is higher than those of the pure CuFeO2 and CuO photocathodes. The effect of the interfacial electric field on the behaviors of photoinduced charge carriers is studied. It is the interfacial electric field that extends the lifetime of photoinduced charge carriers and promotes the charge separation efficiency, which results high performance and good durability.