Z-scheme silver-based p-n junction of AgFeO₂-modified Ag₃VO₄ with enhanced photocatalytic performance

Photocatalysis technology is considered an effective way to solve the problem of water pollution and energy shortage, and is hinged on the development of the photocatalyst. In this study, p-type semiconductor AgFeO₂ and the n-type photocatalyst Ag₃VO₄ formed a p-n junction via a simple hydrothermal method. Compared with pure Ag₃VO₄, the 4 % AgFeO₂-modified Ag₃VO₄ photocatalyst (AgVFe-4) exhibited the best photocatalytic activity: the photodegradation rate of RhB reached 95.1 % within 60 min and possessed good photostability under UV–visible light irradiation. The physical and chemical properties of AgVFe-4 indicated that the composite structure showed a larger special surface area, much lower intensity of photoluminescence, and higher photogenerated carriers separation efficiency. The p-type AgFeO₂ and n-type Ag₃VO₄ could form the p-n junction structure. Based on the analysis of reactive agents, the h⁺, •O₂⁻ and •OH were the main active species during organic pollutions photodegradation, and the photocatalysis process followed the Z-scheme mechanism. Meanwhile, some silver element in the photocatalyst was reduced into Ag⁰, which could act as the recombination center of the photogenerated carriers, further improving the photocatalytic performance. This work may arouse an increasing interest in designing more Z-scheme silver-based p-n junction heterojunction photocatalysts.