Hydrothermal synthesis of type II ZnIn2S4/BiPO4 heterojunction photocatalyst with dandelion-like microflower structure for enhanced photocatalytic degradation of tetracycline under simulated solar light

Abstract

In this work, the type II ZnIn2S4/BiPO4 heterojunction solar -light driven photocatalysts were synthesized via a facile hydrothermal method, which possessed the unique dandelion-like microflower heterostructure. Among all the ZnIn2S4/BiPO4 with different mass ratios, 70 wt% ZnIn2S4/BiPO4 heterojunction displayed the highest photocatalytic activity, which can degrade 84% tetracycline (TC, 40 mg/L) in 90 min and the rate constant is 0.02017 min−1. It is about 1.89 and 3.14 times that of ZnIn2S4 and BiPO4, respectively. The enhanced photocatalytic activity mainly derives from the formed type II heterojunction between ZnIn2S4 and BiPO4, thereby effectively improving the separation efficiency of electron-hole pairs during the photocatalytic reaction. On the basis of the results of active species capturing and ESR experiments, •OH and •O2− were proven two predominant species in the photocatalytic system. This work is expected to provide a design opportunity to construct highly efficient BiPO4-based type II heterojunction photocatalysts for photocatalytic applications of degradation on organic pollutants in aqueous environment.