Evaporation-induced self-assembly Al doped black TiO2 for the degradation of tetracycline hydrochloride under visible light

Light absorption range, recycling stability and charge transfer efficiency are key to the performance of photocatalytic material. Based on these targets, a Al doped TiO2 catalyst was synthesized by the evaporation-induced process, after processed by NaBH4 reduction, the black TiO2 doped with Al was finally prepared. Uv-vis DRS, EPR and XPS analyses confirm the expanded light absorption window (300 nm - 1000 nm) and the introduction of abundant oxygen vacancy after the reduction process. The final product BTiO2/Al-0.5 has a degradation rate of about 84 % over the tetracycline hydrochloride within 60 minutes, the reaction rate constant (k) is 10.6 times higher than the unreduced sample. The dramatic change of photocatalytic ability can be assigned to the broadened visible light absorption, increased charge separation efficiency, narrowed band gap and defect-enriched oxygen vacancy. This work offers insights into the fabrication of TiO2 catalyst and the introduction of oxygen defect.