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

Monoclinic structure silver vanadate Ag{sub 3}VO{sub 4} 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 Ag{sub 3}VO{sub 4} for the decolorization azodye acid red B under visible irradiation were investigated. The Ag{sub 3}VO{sub 4} 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 Ag{sup 0} 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 Ag{sub 3}VO{sub 4} 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.