Ordered macroporous Bi₂O₃/TiO₂ film coated on a rotating disk with enhanced photocatalytic activity under visible irradiation

Ordered macroporous Bi₂O₃/TiO₂ film coated on a rotating disk was prepared by sol-gel method in the presence of polystyrene (PS) microspheres as a template, which showed spectral response in visible region via Bi₂O₃ photosensitizing effect and low photoelectron-hole recombination by forming Bi₂O₃-TiO₂ heterojunctions. Meanwhile, the ordered macropores in the Bi₂O₃/TiO₂ film promoted light-harvesting via multiple reflections and also facilitated reactant adsorption owing to the diminished diffusion limit and enhanced surface hydrophilicity. More importantly, the rotating disk could effectively reduce the light shielding on the Bi₂O₃/TiO₂ film photocatalyst, especially in the color solution. As a result, the as-prepared Bi₂O₃/TiO₂ film exhibited high activity in aqueous visible-light-driven photocatalytic degradation of single and mixed dyes or reduction of Cr⁶⁺ to Cr³⁺.