Synthesis and photocatalytic mechanism of visible-light-driven AgBr/g-C3N4 composite

g-C3N4 is a well-known visible-light-active photocatalyst for the degradation of environmental pollutants. However, its photocatalytic activity is restricted by the small specific surface area and the e(-)/h(+) recombination rate. In order to improve the photocatalytic performance of g-C3N4, AgBr/g-C3N4 composite photocatalyst has been designed. The as-prepared AgBr/g-C3N4 was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectrophotometer (UV-Vis) and room temperature photoluminescence (PL). The photocatalytic activity was evaluated by the photodegradation of methyl orange (MO) under simulated visible-light irradiation. The results show that g-C3N4 is porous structure with a large specific surface area of loading AgBr nanoparticles greatly improves the photocatalytic activity. The AgBr content is optimized to 25 wt%, where the degradation rate of MO can reach 90% after 30 min. The enhancement in photocatalytic performances is mainly attributed to the effective production and transfer of e(-)/h(+) for AgBr can absorb the visible light. Moreover, center dot O-2(-) is demonstrated to be the dominant radical for the photocatalytic degradation of MO.

Automated summary

The AgBr/g-C3N4 composite photocatalyst, with loaded AgBr nanoparticles, significantly enhances the photocatalytic activity of g-C3N4. Optimizing the AgBr content to 25wt%, the degradation rate of MO can reach 90% after 30 minutes. The improvement in photocatalytic performance is mainly attributed to the effective production and transfer of e(-)/h(+) due to the absorption of visible light by AgBr.