Construction of S-scheme BiOCl/layered bimetallic oxide heterojunction for enhanced photocatalytic degradation of bisphenol A

Constructing heterogeneous photocatalysts to enhance the visible light absorption and photo-generated charge carrier separation for efficient degradation of organic pollutants in water samples remained a significant challenge. An S-scheme BiOCl/ZnCrZr-layered bimetallic oxide (LBMO) heterojunction was constructed by depositing BiOCl nanoparticles on ZnCrZr-LBMO. The characterization of material samples were by XRD, SEM, TEM, XPS, FTIR, UV-Vis-DRS, transient photocurrent response, and electrochemical impedance spectroscopy. The photocatalytic efficiency of BiOCl/ZnCrZr-LBMO heterojunction was obviously improved, about 3.95 and 1.68 folds higher than that of pristine BiOCl and ZnCrZr-LBMO, respectively. The fast separation and migration and the prolonged lifetime of photo-generated carriers in the BiOCl/ZnCrZr-LBMO heterojunction were validated by photoelectrochemical tests. The influence factors, versatility, and reusability of the heterojunction were also evaluated. Free radical scavenging test and ESR experiment revealed that ·O2- and h+ active radicals were the dominant active radicals in the BPA degradation. Additionally, BPA degradation intermediates were detected by LC-MS, and the possible degradation pathway of BPA was deduced using density functional theory. This novel S-scheme model heterojunction was expected to provide new ideas for the study of the photocatalytic mechanism and the BPA removal.