Hydrogenated nanoporous TiO2 film on Ti25Nb3Mo2Sn3Zr alloy with enhanced photocatalytic and sterilization activities driven by visible light

Anatase TiO2 film with highly-ordered nanoporous structure was successfully synthesized on Ti25Nb3Mo2Sn3Zr (TLM) alloy through a simple two-step anodization method and a subsequent hydrogenated process. The results show that the obtained TiO2 film on TLM alloy presents a thickness of 900 nm and contains numerous oxygen vacancies. Furthermore, the concentration of oxygen vacancies can be tuned by controlling the temperature of hydrogen annealing. Through the first-principles calculations, it is found that the presence of oxygen vacancy can effectively narrow the band gap of TiO2 and thus expand light absorption range of TiO2 to visible light. The sample hydrogenated at 400 °C displays good photocatalytic and photocatalytic sterilization activities, which can be ascribed to the special structure, enhanced crystallinity and oxygen vacancies content of TiO2 film. These features make the material a good candidate in practical application.