The spherical hexagonal phase tungsten oxide (h?WO3) was synthesized by precipitation method. Then a series of hexagonal/monoclinic WO3(h/m?WO3) phase junction photocatalysts were controllable fabricated by regulating the phase transition process from hexagonal to monoclinic phase. The crystal phase structure and phase composition, particle size and specific surface area of these WO3 catalysts were characterized by X?ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). The experimental results of photocatalytic O2 evolution show that compared with the pure hexagonal phase WO3, the h/m?WO3 with suitable crystal phase composition exhibits remarkable photocatalytic performance. Based on the band positions of hexagonal and monoclinic phases, the surface photovoltage (SPV) characterization results show that the formation of h/m?WO3 phase junction significantly promotes the efficient separation of photogenerated electrons and holes on the surface of the catalyst, and then improves the photocatalytic activity of WO3 catalyst.
