One–step synthesis of sheet–like ZnIn2S4 with exposed (110) facet for efficient reduction of Cr(VI) under visible light

Flower–shaped ZnIn 2 S 4 made by the traditional solvothermal method has a high rate of e – –h + recombination, limiting the photocatalytic reactions and its application. To address this issue, potassium sodium tartrate was added during solvothermal synthesis process to prepare ZnIn 2 S 4 photocatalysts with excellent photocatalytic performance. When the added dosage of potassium sodium tartrate was 0.4 g, the obtained ZnIn 2 S 4 photocatalysts (ZIS–0.4) showed a sheet–like structure and exposed more active (110) facet. Multiple characterization methods indicated that ZIS–0.4 exhibited the highest separation efficiency of photogenerated e – –h + pairs and electron migration. As a result, ZIS–0.4 showed the most superior photocatalytic efficiency in reducing Cr(VI). Following 20 minutes of exposure to visible light, ZIS–0.4 achieved a reduction rate of 99.3 % for Cr (VI), while the reduction efficiency of flower–shaped ZnIn 2 S 4 prepared without potassium sodium tartrate (ZIS–0) was only 28.5 %. The pseudo–first order kinetic reaction rate constant of ZIS–0.4 (0.244 min –1 ) was 15.25 times higher than ZIS–0 (0.016 min –1 ). Electron paramagnetic resonance and radical trapping experiments have verified that the main reactive substances were e – and ·O 2 – in Cr(VI) reduction process.