Construction of BiOCl/CuBi2O4 S-scheme heterojunction with oxygen vacancy for enhanced photocatalytic diclofenac degradation and nitric oxide removal

Construction of step-scheme (S-scheme) heterojunction with superior redox ability is emerging to be an efficient way to develop high-efficiency photocatalysts for environmental pollution control. Herein, a new S-scheme heterojunction photocatalyst built from BiOCl with oxygen vacancies and CuBi2O4 was developed. Compared to pristine CuBi2O4 and BiOCl, this S-scheme heterojunction photocatalysts (BOC/CBO) show enhanced photocatalytic performance in removing aqueous diclofenac (DCF) and gaseous nitric oxide (NO) under visible light irradiation, which is mainly ascribed to the improved charge separation and transfer and redox ability by the S-scheme heterojunction structure and the enhanced catalytic oxidation by tunning the coordination structure and electronic states of O2 by oxygen vacancies. Further, the detailed DCF degradation pathways were studied and confirmed by high performance liquid chromatography–mass spectrometer (HPLC–MS). At last, a possible photocatalytic reaction mechanism based on such a S-scheme heterojunction (BOC/CBO) is proposed. This study provides an insight in constructing high-performance S-scheme heterojunction photocatalysts for environmental pollution remediation.