An innovative ZnInS/ZnInS homojunction photocatalyst with enhanced interfacial charge transfer for the highly efficient degradation of tetracycline under visible radiation.

The interfacial charge transfer ability is a decisive factor influencing the photocatalytic performance of composite photocatalysts. Compared with heterojunctions that combine two or more semiconductors with different properties, homojunctions that combine two semiconductors with similar properties can accelerate the interfacial charge shift and achieve higher photocatalyticability. In this study, a ZnInS/ZnInS homojunction photocatalyst (ZIS-5) with a ZnInS to ZnInS molar ratio of 5:1 was synthesized by selecting ZnInS nano-microspheres as the substrate material and growing ZnInS flocs on the nano-microspheres. The photocatalytic performance of the ZIS-5 homojunction was assessed by using tetracycline (TC) as a typical pollutant. The photocatalytic performance and mineralization rate of the ZIS-5 homojunction were significantly improved compared with those of ZnInS and ZnInS, and its photocatalytic performance was increased by 10.2% and 20.9%, compared with ZnInS and ZnInS, respectively, while the mineralization rate was enhanced by 22.78% and 43.28%, respectively. The results of the comparison experiment revealed that the interfacial electron transfer ability of the ZIS-5 homojunction is 1.6 times that of the g-CN/ZnInS-5 heterojunction. The density functional theory (DFT) computation and Mott-Schottky plots verified the formation of an internal electric field. The toxicity analysis showed that the ZIS-5 homojunction system effectively reduced the toxicity of TC. This work supplies a valuable route for inventing catalysts with efficient photocatalytic performances.