Carbon cloth@SnS2 nanosheet array catalysts for efficient microwave induced catalytic reduction of Cr(VI): Experiment and DFT study

Abstract

Aqueous hexavalent chromium (Cr(VI)) is an environmental safety problem that seriously threatens ecosystems and human health. Herein, SnS2 nanosheet array catalysts on carbon cloth (CC) for microwave-induced catalytic reduction of Cr(VI) were prepared by a simple hydrothermal method. Benefiting from the unique interfacial and the improved electron transfer effect between the SnS2 nanosheet arrays and the CC substrate, the reduction ratio of the CC@SnS2 nanosheet array catalysts reached 100 % for a Cr(VI) solution (50 mg/L) under 35 min-microwave treatment at a frequency of 2.45 GHz and a power of 300 W. Density functional theory (DFT) calculations reveal that Cr2O72− ions were more easily adsorbed on S atoms than HCrO4– ions in an acidic solution, indicating that the activity of S atoms was evidently superior to that of Sn atoms in CC@SnS2 nanosheet arrays. This work provides an in-depth understanding of the mechanism of microwave-catalyzed removal of Cr(VI) and paves a new avenue for designing highly efficient microwave catalysts for wastewater treatment.