Photoactivity and Hydrophilicity of B and Ni Co-Doped TiO<sub>2</sub> Films

Abstract

The effect of Ni doping in Ni and B co-doped TiO2 composite films on photocatalytic reaction and hydrophilic property were investigated. The TiO2 composite films were prepared by sol-gel and coated on glass substrates by dipping methods. These composite thin films were calcined at the temperatures of 400°C for 1 h. Phase formation of TiO2 was characterized by XRD. Morphology of TiO2 composite films were observed by using atomic force microscopy (AFM). The chemical composition and purity of the prepared films were analyzed by EDS, FTIR and FT-Raman spectrometers. The photoactivity of synthesized films was performed by means of degradation of methylene blue dye solution under UV and visible light irradiation. The hydrophilic property was measured in terms of a contact angle of water droplet on the films with and without the activation of UV irradiation. It was found that Ni doping seems to affect on TiO2 phase, crystallinity of the anatase phase, crystallite size of the composite films and band gap energy of the catalysts, resulting in their photocatalytic reaction and hydrophilic property. The crystallinity of anatase increased with an increase in Ni content varied from 0-3 mol% but decreased with an increase in Ni content above 3 mol%. It was found that 3 mol% Ni/B/TiO2 film, having highest crystallinity and smallest crystallite size shows the highest of photocatalytic reaction while 2 mol% Ni/B/TiO2 film provides the most hydrophilic effect. Only anatase phase was found at the calcination temperature of 400°C. The smooth film surfaces exhibits a high hydrophilic property. Super-hydrophilicity (contact angle equal to zero) of all B and Ni co-doped TiO2 films was found at UV irradiation for 25 minutes.