The photocatalytic activity of TiO2 foam and surface modified binary oxide titania nanoparticles

Surface modified titania dioxide composite nanoparticles prepared by hydrogen reduction reaction and a mesoporous TiO2 foam made from a surface modifier and a long chain organic surfactant were characterized by diffractive, spectroscopic and microscopic techniques and studied for their catalytic activity towards the decomposition of an industrial water pollutant, methyl orange. The surface deposition of ruthenium and silicon particles improved the photocatalytic activity of the composite particles resulting in a faster decomposition of the methyl orange compared to commercial TiO2 alone. Modification of TiO2 with RuO2 only offered a marginal benefit over TiO2 while the incorporation of RuO2 and SiO2 into TiO2 resulted in a marked increase in the rate constant and catalytic activity. These results are consistent with the enhanced surface properties of the composite materials resulting from the modification of TiO2 with RuO2 and SiO2. This surface enhancement effects appear synergetic to the charge separation process and hence the photocatalytic results are explained on the basis of a mechanism involving efficient charge transfer across the interfaces of the composites involving photogenerated electron–hole pairs. Results obtained in this study show that the percentage degradation after 1 h of illumination was 47.15% for TiO2 foam, 75.5 and 106.4%, respectively, for TiO2/RuO2 (SiO2 5%, w/w) and TiO2/RuO2(SiO2 10%, w/w) and 34.15% for commercial TiO2.