Insights into the superior singlet oxygen production for BiVO4/Bi4Ti3O12 S-scheme heterojunction catalysts

The production of singlet oxygen during advanced oxidation processes is restricted by the precise cooperation of photogenerated carriers, energy band potentials, and surface adsorbed oxygen. Herein, we report that an in situ BiVO4/Bi4Ti3O12 S-scheme heterojunction could form oxygen vacancies by constructing crystal defects and effectively produce singlet oxygen by adsorbing oxygen on the surface. Moreover, the novel S-scheme heterojunction not only facilitates the separation of charge carriers, but also accumulates photogenerated electrons on the conduction band of the BiVO4 nanosheet, and the interaction rate between photogenerated electrons and oxygen adsorption on the surface is improved, which tremendously prolongs the life span of the singlet oxygen. Consequently, the selective oxidation of singlet oxygen was examined by the catalysis of the obstinate aromatic hydrocarbon pollutant, and BiVO4/Bi4Ti3O12, which additionally produced the singlet oxygen, showed superior catalytic performance in comparison with the pristine BiVO4. This study overcomes the current limitation of singlet oxygen production and provides a promising strategy for the development of novel catalysts.