Synthesis of Visible-Light-Activated Yellow AmorphousTiO2Photocatalyst

Abstract

Visible-light-activated yellow amorphousTiO2(yam-TiO2) was synthesised by a simple and organic-free precipitation method. TiN, an alternative precursor forTiO2preparation, was dissolved in hydrogen peroxide under acidic condition(pH∼1)adjusted by nitric acid. The yellow precipitate was obtained after adjusting pH of the resultant red brown solution to 2 withNH4OH. The BET surface area of this sample was 261 m2/g. The visible light photoactivity was evaluated on the basis of the photobleaching of methylene blue (MB) in an aqueous solution by using a 250 W metal halide bulb equipped with UV cutoff filter (λ>420 nm) under aerobic conditions. Yam-TiO2exhibits an interesting property of being both surface adsorbent and photoactive under visible light. It was assigned to theη2-peroxide, an active intermediate form of the addition ofH2O2into crystallinedTiO2photocatalyst. It can be concluded that an active intermediate form of titanium peroxo species in photocatalytic process can be synthesised and used as a visible-light-driven photocatalyst.