ZnIn2S4 grown on nitrogen-doped hollow carbon spheres: An advanced catalyst for Cr(VI) reduction.

Up to now, the environmental damage by heavy metal is getting worse and worse as the development of industry. Meanwhile, hexavalent chromium (Cr(VI)) in wastewater get special attention as its acute toxicity and potential carcinogencity. To solve this problem, we introduce a simple and efficient way to prepare a photocatalyst, ZnIn2S4 grown on nitrogen-doped hollow carbon spheres (ZIS-NHC), which is an effective catalyst that can used to reduce aqueous Cr(VI). This photocatalyst prepared by a three-step strategy. Benefiting from the excellent electrical conductivity and high specific surface area of the NHC which is superior to other carbon material and the favorable band gap of ZnIn2S4 makes ZIS-NHC has superior light-driven photocatalytic efficiency. The ZIS-NHC exhibits an excellent rate of degradation of aqueous Cr(VI) at a concentration of 50 mg/L within 50 min. Moreover, the ZIS-NHC retained excellent stability after five rounds of cycling experiments which was also discussed.