Enhanced photocatalytic performance of TiO2 with tunable oxygen vacancies induced by H2/N2 mixture treatment

Surface treatment can effectively modulate the surface properties of a photocatalyst to hasten the separation and transfer of photoinduced charges, ultimately achieving high photocatalytic performance. Herein, surface treatment of anatase-phase TiO₂ prepared by a hydrothermal method was performed under H₂/N₂ mixed atmosphere. The experimental results demonstrate that roasting TiO₂ in a H₂/N₂ atmosphere can effectively reduce partial Ti⁴⁺ to Ti³⁺, thereby facilitating the production of tunable oxygen vacancies (OVs) by disrupting Ti-O-Ti bonds. OVs can construct defective energy levels to bring about a decrease in the bandgap of TiO₂ and an extension of light absorption range. Moreover, OVs remarkedly improve the separation of photoinduced charges of TiO₂ and accelerate the photocatalytic reaction as active sites. The photocatalytic experimental results demonstrate that TiO₂ exhibits the highest performance when roasting TiO₂ in a H₂/N₂ atmosphere for 2 h, and the photocatalytic degradation rate constant of rhodamine B (RhB) and tetracycline (TC) on this sample under simulated solar light irradiation is 2.24 and 1.11 times higher than that on the reference TiO₂, respectively. These findings provide valuable insights for designing highly efficient photocatalysts for effective water pollution treatment.