Colloidal Cu-doped TiO2 nanocrystals containing oxygen vacancies for highly-efficient photocatalytic degradation of benzene and antibacterial

Development of suitable colloidal photocatalysts with excellent photocatalytic performance under visible light is essential for indoor environmental remediation. In this study, colloidal Cu-doped TiO2 (Cu-TiO2) nanocrystals containing oxygen vacancies (OVs) were synthesized by a facile sol-hydrothermal method and their photocatalytic performances for benzene degradation and antibacterial were investigated. Characterization results revealed that the doping of Cu induced grain size reduction and bandgap narrowing of TiO2 nanocrystals, as well as the formation of abundant OVs in the TiO2 crystal structure, resulting in enhanced light absorption capacity and charge carrier separation efficiency. The optimized colloidal Cu-TiO2 nanocrystals could achieve a maximum degradation rate constant of 0.364 h-1 for the photocatalytic degradation of benzene and a high antibacterial rate of more than 99.99% against both Escherichia coli and Staphylococcus aureus, which were far superior to those of the pristine TiO2. The effects of Cu dopants and OVs on the band structure of TiO2 were revealed by density functional theory (DFT) calculations combined with experimental characterizations, and a possible mechanism for the enhancement of Cu-TiO2 photocatalytic performance was proposed. This work offers a promising method for the synthesis of colloidal TiO2-based nanocrystals with excellent photocatalytic performances for the practical application in indoor environmental remediation.