Fabrication of SiW9Co3/CdIn2S4 heterojunction with boosted photocatalytic performance for H2 generation and Cr(VI) reduction

Developing effective photocatalysts with an enhanced light-harvesting ability and a high charge carrier separation efficiency is a crucial step in the photocatalytic technology for solving energy crisis and reducing environmental pollution. Herein, a series of K₁₀[SiW₉Co₃(H₂O)₃O₃₇]/CdIn₂S₄ (abbr. x % SiW₉Co₃/CIS; x % represents the quality ratio for SiW₉Co₃:CIS, x = 30, 40, 50, 60 and 70) heterojunctions were prepared successfully with a simple hydrothermal method. The compositions, morphologies, catalytic performance and photoelectrochemical properties of the obtained samples were well examined. These SiW₉Co₃/CIS samples demonstrated outstanding visible-light (λ ≥ 420 nm) catalytic performance toward hydrogen generation and Cr(VI) removal with outstanding cycling durability and stability. Particularly, 50 % SiW₉Co₃/CIS had the supreme photocatalytic properties with the hydrogen evolution rate of 783.8 μmol/g·h (AQE = 4.58 %; λ = 420 nm) and the Cr(VI) reduction rate constant of 0.0625 min⁻¹. which was 3.78 and 8.8 folds that of bare CIS (0.0165 min⁻¹) and SiW₉Co₃ (0.0071 min⁻¹), respectively. The boosted catalytic capability could be assigned to the improvement of the number of active sites, the visible light absorption, and the separation efficiency of photogenerated carriers. The current work offers new perspectives for designing and constructing POMs/semiconductor photocatalytic system with effective catalytic property for Cr(VI) removal and hydrogen evolution.