An experimental and theoretical study on the photocatalytic antibacterial activity of boron-doped TiO2 nanoparticles

Boron-doped titanium dioxide nanoparticles (B-TiO2 NPs) were prepared by a sol-gel method. The physicochemical properties of B-TiO2 NPs were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The band structure and electrical properties of B-TiO2 NPs were investigated using the first-principle. The effects of the concentration gradient of doping B ions on the photocatalytic antibacterial activity of B-TiO2 NPs under visible-light irradiation were investigated by the inhibition zone method and the shaking flask method. The experimental results show that B-TiO2 NPs are mainly composed of the anatase phase, but no B-related phase was observed. With the increase of the doping amount of boron ions, the particle size decreases and the specific surface area increases. B atoms mainly exist in the form of substitutional dopant and interstitial dopant. Theoretical calculations reveal that B atoms in the TiO2 matrix exist much more easily as interstitial dopant, but B-TiO2 NPs composed of B substituted dopant have better photocatalytic performance. The results of the antibacterial assays show that B-TiO2 NPs have strong antibacterial activities and some bactericidal activities. Finally, the mechanism of the antibacterial activity of B-TiO2 NPs are examined.

Automated summary

Boron-doped titanium dioxide nanoparticles (B-TiO2 NPs) were prepared by a sol-gel method and characterized by various techniques. The experimental results demonstrate that doping boron ions can enhance the photocatalytic antibacterial performance of B-TiO2 NPs, with boron atoms mainly existing as substitutional and interstitial dopants.