Study on Photocatalytic Activity of Ag2O Modified BiOI/g-C3N4 Composite Photocatalyst for Degradation of RhB

Degradation of harmful pollutants is the key to water pollution control. Herein, a series of BiOI/g-C 3 N 4 -Ag 2 O (BCNA) heterojunction photocatalysts were prepared by a simple liquid-phase synthesis method for photocatalytic degradation of organic pollutants under visible light. The crystal structure, morphology, and elemental composition of the synthesized photocatalysts were characterized by x-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and x-ray photoelectron spectroscopy (XPS). The experimental results showed that compared with g-C 3 N 4 and BiOI, BiOI/g-C 3 N 4 -Ag 2 O composite showed the best photocatalytic activity when the Ag 2 O loading was 14.68 wt.%, and the removal rate of rhodamine B (RhB) could reach 98% after 30 min, and the photodegradation showed good stability through the cycle tests. In addition, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), photoluminescence excitation spectrum (PL), and photoelectrochemical measurements confirmed that the enhanced photoactivity of BiOI/ g-C 3 N 4 -Ag 2 O is due to the formation of ternary heterojunction, which not only amplifies the visible light response of g-C 3 N 4 but also improves the separation and migration rate of photoinduced carriers. Finally, a possible mechanism of charge separation and transfer for ternary heterojunction photocatalysts was proposed. This study extends the application range of g-C 3 N 4 for RhB degradation and provided a new opportunity for environmental remediation.