A Hybrid S-Scheme WS2/BiOI Heterojunction Photocatalyst for Wastewater Treatment

There is a growing demand for efficient methods to decrease hazardous organic contaminants in wastewater. Herein, a novel S-scheme WS2/BiOI heterojunction photocatalyst was prepared by a one-pot solvothermal process. The structural morphology, crystal structure and optical absorption studies were studied. The sugar-like nanocrystals of WS2 are deposited on 3D-BiOI marigold flowers, providing high surface area with increased visible light absorption. The photocatalytic activity of the synthesized materials was studied by visible light degradation of Rhodamine-B (RhB). The optimized 20 wt.% WS2 in the composite photocatalyst (band gap 2.25 eV) exhibited a 98.9 % photocatalytic degradation activity with a rate constant of 0.0940 min(-1) with performance retained after 3 consecutive recycling runs. Photoelectrochemical studies revealed excellent stability, increased separation and migration ability of charge carriers with lower charge resistance in the optimized WS2/BiOI photocatalyst.