P-doped g-C3N4/BiOCl Z-type heterojunction with N and O double vacancies and synergistically enhanced photocatalytic activity under sunlight irradiation

Abstract

The use of inexhaustible natural sunlight is a highly effective method for wastewater treatment. In this study, P-doped g-C3N4/BiOCl Z-type heterojunction semiconductor photocatalyst with N and O double vacancies was constructed through calcination and coprecipitation. The obtained results revealed that the degradation rate of Rhodamine B (Rh B) reached 0.05642 min −1 within 60 min under visible light irradiation with a 300 W xenon lamp (λ≥400 nm), which was 73 and 8 times that of pure CN and BiOCl, respectively. Under natural sunlight irradiation, Rh B was almost completely degraded within 6 min, and its degradation rate reached 0.95641 min−1, which was 17 times that of Rh B simulated by visible light in the laboratory. The doping of non-metallic P and construction of a heterojunction significantly improved the photocatalytic activity of P-doped g-C3N4/BiOCl, which could be attributed to the synergistic effect of N, O vacancies and heterojunction structure interfaces on the composite material surface, which apparently expanded the light absorption range, promoted the transfer of charge, increased the quantity of active sites for the light-induced reaction, and improved the redox ability of the catalyst. The heterojunction semiconductor with surface defects prepared in this study provides a green approach for future wastewater treatment applications.