AgFeO2 Nanoparticle/ZnIn2S4 Microsphere p-n Heterojunctions with Hierarchical Nanostructures for Efficient Visible-Light-Driven H2 Evolution

The main bottleneck of photocatalytic H-2 evolution is the high recombination rate of photoexcited electrons and holes. Herein, a novel composite comprising p-type AgFeO2 nanoparticles loaded on the surface of n-type ZnIn2S4 microspheres was successfully synthesized via an ultrasound-assisted method. Because of the intimate interface between AgFeO2 and ZnIn2S4 and the formed internal electric field, the ZnIn2S4/AgFeO2 p-n heterojunction has more efficient separation and migration of photoexcited charge carriers, thereby significantly increasing the photocatalytic H-2 evolution rate. Compared with pure ZnIn2S4, ZnIn2S4/AgFeO2-3 composite showed a 30-fold increase in H-2 evolution rate (9.14 mmol h(-1) g(-1)). Meanwhile, various characterization techniques provided powerful proof for the formation of the p-n heterojunction and the transport pathway of the charge carrier. The specific photocatalytic mechanism was discussed for the visible- light photocatalytic H-2 evolution. This work offers a valuable guidance toward the design and fabricate other p-n hetero-junctions having high photocatalytic performance for use in the energy and environment fields.

Automated summary

This study successfully synthesized a ZnIn2S4/AgFeO2 p-n heterojunction composite, which significantly increased the photocatalytic H-2 evolution rate. Various characterization techniques provided strong evidence for the formation of the p-n heterojunction and the charge carrier transport pathway.