Fabrication and Photocatalytic Activity of Nanoporous WO3 Film

Nanoporous tungsten oxide (WO3) films with a thickness of 500 nm and pore size of about 80-100 nm are fabricated by chemical anodization of a W foil in a 1 M Na2SO4 solution with 0.5 wt% NaF (pH 4.0) at 40 V. The effect of anodization voltage on the morphology of WO3 films was investigated by evaluating the anodization current and the dissolution concentration of W in electrolyte during anodization process. The photoelectrochemical properties and photocatalytic activity of the nanoporous WO3 films are investigated under visible light irradiation. The nanoporous WO3 structure is a sensitive visible light photocatalyst that can be used to decompose contamination and our results show that the porous film has better photoactivity than a dense structure.