Highly photoactive and stable TiO2 coatings on sintered glass

TiO2 coatings on sintered borosilicate glass (100-160 mum pore size) were prepared employing a synthetic route based on the hydrolysis of titanium oxysulfate (TiOSO4). The morphology of the coatings was studied by scanning electron microscopy (SEM), showing TiO2 layers with a smooth and homogeneous structure covering the entire surface of the particles forming the sintered glass. The photocatalytic activity of the TiO2 coatings was analysed employing the photooxidation of glucose in water as test reaction. The influence of the preparation conditions of the coatings on their photoactivities was studied. It was found that the starting concentration of precursor and the ageing time were two parameters of significant relevance for the final properties of the catalysts. With specific preparation parameters, photonic efficiencies up to 4% for the total mineralisation of glucose in water could be reached. The effect of the reaction pH during the photocatalytic tests on the efficiency of these coatings was also studied, with the glucose degradation being more favourable at high values of pH. Stability and lifetime of the coatings were tested following the evolution of their photocatalytic activity for more than 4000 It of continuous operation. No appreciable degradation of the coatings could be observed during this time. (C) 2004 Elsevier B.V. All rights reserved.