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

[Display omitted] •Sonochemical synthesis of Bi2O3-ZnO/ bentonite clay nanocomposites was demonstrated.•Uniform distribution of crystalline and spherical metal oxides over the support was obtained.•Synthesized catalyst showed excellent photocatalytic activity for congo red (CR) dye degradation.•The rate constant of 0.029 min−1 was obtained towards photocatalytic degradation of CR.•Excellent stability and reusability (5 times) was shown by the synthesized photocatalyst. 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.