Modulated construction of S-deficient catalytically active site-rich CoS for enhanced photocatalytic reduction of Cr(VI)

As one of the most critical approaches to resolve the environmental pollution, photocatalytic reduction of potassium dichromate (Cr(VI)) into non-toxic substance has attracted more and more attention. Recent advances in the removal of Cr(VI) from wastewater using semiconductor materials with rich-defect are highlighted. Herein, we prepared defect-rich CoS porous nanostructure through solvothermal and then used for the removal of Cr(VI) from wastewater. The S vacancy defects are introduced on the CoS to achieve rich active sites, which distinctly enhance the photocatalytic reduction of Cr(VI) performance of WDCoS-3. The results show that WDCoS-3 exhibits excellent photocatalytic reduction of Cr(VI) activity up to 96%, 5 times higher than the CoS-Water and the better than the CoS-DMF. The ESR and EPR results proved the main active species were •O2–, e- and S-defect in solar-light driven photocatalytic system. The enhanced photocatalytic performance of the defect-rich CoS porous nanostructure was due to S defect-rich active sites act as obstruction centers for the efficient transfer and utilization of photo-induced carriers. As a consequence, the photocatalytic performance of defect-rich WDCoS-3 porous nanostructure in photocatalytic reduction of Cr(VI) is significantly better.