Preparation and visible-light activity of silver vanadate for the degradation of pollutants

Monoclinic structure silver vanadate Ag3VO4 was prepared by hydrothermal process. The effects of the ratio of silver to vanadium in starting material, hydrothermal temperature on surface morphologies, structure and photoactivity of Ag3VO4 for the decolorization azodye acid red B under visible irradiation were investigated. The Ag3VO4 prepared in the excess vanadium at 160 deg. C for 48 h exhibited highest visible-light-driven activity. Excess vanadium in the preparation increased the crystallinity and suppressed the formation of grain boundaries, while the formation of Ag0 on the surface of the catalyst promoting the electron-hole separation and interfacial charge transfer, resulting in an increase in the photocatalytic activity. Furthermore, the activity of the Ag3VO4 was increased by 11 times when NiO was loaded, which also shows high activities for the decomposition of phenol and aniline. It is possible due to the formation of a short-circuited microphotoelectrochemical cell enhancing the separation of photogenerated electron-hole pairs