One-step hydrothermal preparation of TiO₂/WO₃ nanocomposite films on anodized stainless steel for photocatalytic degradation of organic pollutants

TiO₂/WO₃ nanocomposite film was deposited on anodized stainless steel by one step hydrothermal reaction. Polished stainless steel foil was anodized to form nanopore arrays on the surface that is favorable for the immobilization of photocatalyst. The TiO₂/WO₃ nanocomposite film prepared in 0.01 mol/L (NH₄)₂TiF₆ and 0.0066 mol/L Na₂WO₄ solution at 120 °C for 3 h exhibits the maximum photocatalytic activity, which is five times higher than that of pure TiO₂ film and eight times higher than that of pure WO₃ film. As compared with the pure TiO₂ film, the main absorption edge of the WO₃/TiO₂ nanocomposite film shifts toward visible region and the absorption intensity is obviously improved. The nanocomposite film has a preferable crystallinity of anatase TiO₂ and the monoclinic WO₃, as revealed by X-ray diffraction and X-ray photoelectron spectroscopy. Scanning electron microscopy images show that the nanocomposite film is homogenous in size distribution and uniform in morphology. The high resolution transmission electron microscopy images further demonstrate the formation of mixed crystal between WO₃ and TiO₂ nanoparticles. The excellent photocatalytic activity of the nanocomposite film should be attributed to the formation of heterojunction between TiO₂ and WO₃ nanoparticles that can facilitate the separation of photo-generated electron–hole pairs. - Highlights: • TiO₂/WO₃ nanocomposite film on anodized stainless steel by hydrothermal deposition • The anodized stainless steel offered a favorable substrate to immobilize the photocatalyst. • The photocatalytic activity of TiO₂/WO₃ film is significantly higher than that of TiO₂ film. • The heterojunction between TiO₂ and WO₃ leads to excellent photocatalytic activity