S-scheme heterojunction Bi2O3-ZnO/Bentonite clay composite with enhanced photocatalytic performance

The industrial waste water is always a bottleneck problem in the modern civilization of the present era. In a quest to develop effective methods for the elimination of lethal pollutants from the waste water and water remediation, this work is focused on the development of a rapid and proficient approach for preparing supported binary metal oxide catalyst for photocatalytic advance oxidation process used in waste water treatment applications. The sonochemical synthesis of novel S-scheme Bi2O3-ZnO supported on bentonite clay nanocomposite is demonstrated for the photocatalytic oxidation of Congo red (CR). The effectiveness of catalyst to degrade CR dye was determined using UV-visible spectroscopy under different experimental conditions such as catalyst loading, time of UV exposure and concentration of H2O2. The synthesized catalyst demonstrated excellent photocatalytic oxidation under UV light. The pseudo-first-order rate constant obtained for this reaction was 0.029 min(-1). Nearly total degradation of CR dye was achieved in 1 h under UV light irradiation using the catalyst. This remarkable increase in the catalytic performance of Bi2O3-ZnO/bentonite clay is due to the S-scheme mechanism of charge transfer between ZnO and Bi2O3, through enhanced redox potential. Also, its efficient recoverability and reusability (5 times) establish its promising potential for catalytic applications.