Highly efficient CdS/SbVO4 composites for visible-light-driven Cr(VI) reduction

Heavy metal contamination is a grave environmental concern due to its severe implications for human health and ecosystems, causing carcinogenic and teratogenic effects. This study addresses this pressing issue by exploring the synthesis and application of CdS/SbVO4 composites as effective photocatalysts. These composites were synthesized by a streamlined two-step hydrothermal method, with investigations conducted on varying molar ratios. The composite with a molar ratio of 0.2:1 demonstrated superior Cr(VI) photoreduction properties under visible light irradiation, exhibiting an efficiency quadruple that of pure SbVO4. This enhancement in photocatalytic activity is credited to the augmented separation of electrons and holes facilitated by the integration of narrow band gap materials within the composite. Electrochemical tests indicated the electron transfer mechanism and identified the primary active centers of the samples. The detailed photocatalytic mechanism of the composite was further discussed, grounded on insights derived from free radical trapping experiments and electron spin resonance analyses.