NaBH4 modified TiO2: Defect site enhancement related to its photocatalytic activity

Defected TiO2 nano-powder was synthesized by applying NaBH4 assisted heat treatment (300–450 °C) on pristine TiO2 nanoparticles under argon atmosphere. By increasing the process temperature, higher defect percentage (oxygen vacancies) can be achieved. In line with the defect concentration, significant enhancement of absorption in visible light also observed. Further characterization reveal that the defect created via NaBH4 treatment is mainly bulk defect which trigger recombination of electrons and holes. The concentration of defect contributes to the photocatalytic activity. Controllable defect produced by NaBH4 reduction at 350 °C lead to the better photocatalytic activity performance of Rhodamine B degradation under simulated solar light. [Display omitted] •Defects have been successfully introduced to pristine TiO2 via NaBH4 treatment.•Defects confirmed to be oxygen vacancies formed in bulk and surface of materials.•Photocatalytic activity of defected TiO2 was evaluated under solar light irradiation.•Better photocatalytic activity can be achieved by controlling the defect.