Photo-catalytic Ni/Co co-doped TiO2 nanoparticles for glazed Ceramic Tiles

Self-cleaning and anti-bacterial activities of the photo-catalyst titanium dioxide make it a superior compound for use in the ceramics and glass industry. In order to achieve high self-cleaning efficiency for building products, it is important that Titania is present as anatase phase. Moreover, it is desirable that the particle sizes are in Nano-range, so that a large enough surface area is available for enhanced catalytic performance. In the present paper, Cobalt and Nickel co-doped (4%mol Ni and 4%mol Co doped TiO2) and un-doped TiO2 Nano powders have been prepared by sol–gel technique and calcinated at temperatures ranging from 475°C to 1075°C. Ni/Co co-doped TiO2, postponed the anatase to rutile transformation of TiO2 by about 200C, such that after calcination at 775 C, no rutile was detected for 4 mol% Ni/Co co-doped TiO2. A systematic decreasing on crystallite size and increasing on specific surface area of Ni/Co co-doped TiO2 were observed. Photo-catalytic activity of anatase polymorph was measured by the decomposition rate of methylene blue under sunlight illumination. The results showed enhanced catalysis under visible light for Ni/Co co-doped TiO2 as compared to pure TiO2. The enhanced performance was attributed to surface chemistry change associated with a slight shift in the band gap.