Construction of core-shell ZnS@In2S3 rhombic dodecahedron Z-scheme heterojunction structure: Enhanced photocatalytic activity and mechanism insight

Abstract

Photocatalytic degradation of organic pollutants was one of the significant ways to solve the problem of antibiotic pollution in the environment. In this work, the core-shell structure of ZnS@In2S3 rhombic dodecahedron (ZnS@In2S3 RD) Z-scheme heterojunction was synthesized. The In2S3 shell wraps the ZnS core, close coaxial contact and effectively promote the separation of electrons and holes through the In-S-Zn bond, and the redox ability of the In2S3 and ZnS RD could be maintained crediting to the Z-scheme system heterojunction. Marvelously, 100 mL, 20 mg/L TC-HCl solution can be completely degraded within 20 min, and the apparent reaction rate constant reaches 0.284 min−1 that far exceeds majority of the previously reported sulfide photocatalyst. Notably, the Finite Element Method (FEM) based on Comsol software was used to simulate the electric field distribution to verify the electric field enhancement effect caused by ZnS@In2S3 RD at the interface. In addition, the intermediate products of the photocatalytic degradation process were monitored by HPLC-MS to understand the degradation pathways. Finally, a possible photocatalytic degradation mechanism was proposed through experimental results and theoretical analysis. This work provides a reference for the development of efficient antibiotic photodegradation catalysts.