Study Of Synthesis And Visible Light Photocatalytic Properties Of Ag/AgCl/BiMg₂VO₆Composite Photocatalyst

The global energy crisis and environment pollution have attracted tremendous attentions from many countries. The research of visible-light photocatalyst with high utilization efficiency of solar energy to split water into hydrogen or degrade organic pollutant, has become a hot research covering materials science, chemistry and environmental science in recent years. Many Bi-based photocatalysts have been found to be very active under visible-light irradiation, which are attributed to their special crystal and electronic structure. In addition, the high efficient plasmonic Ag/AgX photocatalysts have also been developed and aroused broad interesting and concerning because of their stable structure and strong UV-vis absorption due to the surface plasmon resonance. Therefore, both of them have been paid much attention and studied in this paper.In this paper, a novel composite photocatalyst Ag/AgCl/BiMg2VO6was synthesized by depositing Ag/AgCl nanoparticles on BiMg2VO6substrate via a precipitation-photoreduction method. The photocatalytic activity of photocatalysts for degradation of acid red G (ARG) under visible light irradiation was studied, and the mechanics for degradation of ARG by catalysts was discussed as well.The substrate material BiMg2VO6was synthesized by a sol-gel method using Bi(NO3)3·5H2O, Mg(NO3)2·6H2O and NH4VO3as the starting materials, and then the composite photocatalyst Ag/AgCl/BiMg2VO6was obtained by depositing Ag/AgCl NPs into the BiMg2VO6powder via an precipitation-photoreduction method. The Ag/AgCl/BiMg2VO6powders were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectrophotometer (DRS).ARG (50mg/L) dye, simulating organic pollutant wastewater, was selected to investigate the photocatalytic activities of Ag/AgCl/BiMg2VO6powders under visible-light irradiation (λ≥420nm). Some experimental factors of photocatlytic degradation were also studied, such as initial concentration of ARG solution, catalyst dosage and photoreduction time. The experimental results showed that the as-prepared sample exhibited high photocatalytic activity for the degradation of ARG solution.The mechanism on the photocatalytic degradation of ARG was discussed through UV-vis spectrum analysis, TA-PL analysis and the active species scavenger experiments in the photocatalytic reaction. The results showed that most of the azo and condensed nucleus structure of ARG dye could be destroyed by photocatalysis. And that·OH was not the dominant photooxidant, while the direct hole transfers and·O2-were involved as the active species in the photocatalytic reaction. A possible organic pollutants photodegradation mechanism by visible light driven Ag/AgCl/BiMg2VO6was proposed.