Highly Efficient Solar Hydrogen Evolution by Photoelectro-Chemical Water Splitting over ZnFe2O4-ZnO Heterojunction

Abstract ZnFe 2 O 4 -ZnO heterojunction thin-films were fabricated by the composite photocatalyst, which was first synthesized by a freeze-drying process and followed by a simple chemical bath way in the condition of low temperature. The ZnFe 2 O 4 -ZnO heterojunction thin-film exhibited high efficiency to get hydrogen with photoelectrochemical method under visible-light irradiation. The property with photoinduced charge-transfer of p -type ZnFe 2 O 4 was improved significantly by Cooperating with n -type ZnO. The heterojunction at the interface between the ZnO and ZnFe 2 O 4 efficiently reduced the recombination of photoinduced electron-hole pairs, and thus increasing the lifetime of charge carriers and enhancing the phototo-current efficiency of the ZnFe 2 O 4 -ZnO heterojunctions. It was found the heterostructure between two different kinds of semiconductors is important in affecting the dynamic properties of the photo-to-current conversion efficiency and their photogenerated charge carriers.