Designing Z-scheme InO @ZnInS core-shell heterojunctions for enhanced photocatalytic multi-pollutant removal.

In water bodies, the coexistence of and interaction between multiple pollutants complicate remediation. In this study, the InO @ZnInS Z-scheme heterojunction with a stratified core-shell structure was constructed and used to remove multiple pollutants (tetracycline hydrochloride and Cr(VI)). The large number of active sites and the mechanism of photogenerated charge separation ensured the substantially enhanced catalytic activity of this photocatalyst, making it superior to InO nanospheres and pure ZnInS. The optimised InO @ZnInS nano-flowers (InO @ZnInS NFs) realised 99.8% removal of tetracycline hydrochloride and 100% removal of Cr(VI) within 60 min under visible-light. The material's high stability was demonstrated by five experiment cycles. Effects of organics, inorganics, and pH about the photocatalytic performance of the optimised InO @ZnInS NFs when tetracycline hydrochloride and Cr(VI) coexist were also explored. Finally, the intermediates and degradation pathways were analysed, and the possible photocatalytic mechanism was also investigated by performing density functional theory calculations.