Dual electron transfer path and LSPR photothermal enhancement in BiOCl@ZnIn₂S₄ heterojunction for enhanced photocatalytic H₂ evolution, H₂O₂ production and tetracycline removal

A well-designed catalyst structure can significantly enhance the efficiency of photocatalytic light-trapping. Herein, the local surface plasmon resonance effect (LSPR) generated by introducing BiOCl nanosheets effectively broadened the photoresponsive range of ZnIn₂S₄ (ZIS), and the photothermal effect of BiOCl increased the temperature of the reaction system of the BiOCl@ZIS-1% composites, which in turn improved the photo-thermal performance and light-harvesting efficiency of the catalyst. The improved photothermal effect promoted the transfer rate of charge carriers across the heterojunction and enhanced the surface reaction kinetics. In addition, Kelvin probe force microscopy and density functional theory (DFT) calculations showed that the difference of merit between BiOCl and ZIS led to the generation of an internal electric field, which not only enhanced the efficiency of photogenerated charges to separate and migrate but also promoted the photocatalytic H₂ production (13.69 mmol g⁻¹ h⁻¹), H₂O₂ generation (9670 μM g⁻¹ h⁻¹) and tetracycline degradation performance (86.2%). In addition, a possible reaction mechanism for photothermal-assisted photocatalysis was presented. Thus, this research proposes a possible direction for constructing a visible photothermal-assisted photocatalytic reaction system.