Construction of CdSe/ZnIn2S4 Z-Scheme heterojunction for enhanced photocatalytic degradation of tetracycline

ZnIn 2 S 4 as an energy band narrow photocatalyst has attracted extensive attentions in water remediation, but the fast carrier recombination efficiency hinders its further utilization. An effective strategy is to boost photocarrier separation and enhance photocatalysis performance by building heterojunction. Here, a simple in-situ deposition method is used to create a unique CdSe/ZnIn 2 S 4 heterojunction structure. By varying the CdSe content, CdSe/ZnIn 2 S 4 composites can be synthesized with diffident photocatalytic properties. The optimal photocatalytic efficiency of CdSe/ZnIn 2 S 4 composite is obtained when 1.0 % CdSe addition, while an overdose of CdSe QDs results in a deterioration of photocatalytic efficiency. 93 % tetracycline (TC) degradation could be attained. And the degradation rate is 1.9 and 2.3 times higher than pure ZnIn 2 S 4 and CdSe. In addition, the CdSe/ZnIn 2 S 4 photocatalytic mechanism complies with the Z-Scheme. In the photodegradation process, the superoxide radicals (·O 2 – ) and holes (h + ) are the primary active agents.