Abstract
CaCO(3)/BiO(2-x)/CdS (CCO/BO/CS) ternary composite photocatalyst was synthesized via a hydrothermal method combined with chemical precipitation, and its performance in the photocatalytic reduction of hexavalent chromium (Cr(VI)) under visible light was systematically investigated. Compared with pure BiO(2-x), CdS, and binary BiO(2-x)/CdS composites, the CCO/BO/CS system exhibited significantly enhanced Cr(VI) reduction activity. Specifically, the CCO/BO/CS (0.75:1:2 wt) composite achieved a Cr(VI) reduction efficiency of 94.53% within 30 min of visible light irradiation-approximately 94.6 times and 6.1 times higher than those of BiO(2-x) (1.0%) and CdS (15.52%). Photoelectrochemical and trapping experiments revealed that the enhanced performance stems from improved charge separation, accelerated interfacial electron transfer, and the promotional role of CaCO(3)-likely through lattice distortion-rather than direct photocatalytic participation. This study highlights the innovation of incorporating low-cost, eco-friendly calcium carbonate into semiconductor-based photocatalysts to induce lattice distortion for enhanced charge separation, as an effective strategy for improving the reduction efficiency of Cr(VI).