Constructing a novel hierarchical ZnMoO₄/BiOI heterojunction for efficient photocatalytic degradation of tetracycline

The series of novel visible-light-driven ZnMoO₄/BiOI heterojunctions were successfully fabricated via in situ solvothermal directly growth of BiOI on the surface of ZnMoO₄ plate-like, and the ratio of composite was optimized by increasing of ZnMoO₄ loading. The phase, morphology and optical characteristics of obtained ZnMoO₄/BiOI heterojunctions were systematically characterized using several analytical measures. The photocatalytic performance was assessed by degrading tetracycline (TC) under visible light irradiation. The results showed that the 30 wt% ZnMoO₄/BiOI (ZB-30) composite exhibited highest photocatalytic performance than others. The enhanced photocatalytic efficiency could be attributed to the appropriate band gap of composites, strong visible light response, the formation of heterojunctions with close interface contact and generation and separation of photoinduced carriers. The trapping experiments indicated that ^·O₂⁻, h⁺ and ^·OH radicals played distinct parts in the photodegradation process, and ^·O₂⁻ radicals was the dominant specie. In addition, a probable photocatalytic mechanism of the fabricated composites was also put forward.