Sol-gel derived functional coatings of titania-silica-lanthanum phosphate nanocomposite

摘要

A composite coating containing silica and lanthanum phosphate in nanotitania is expected to introduce multi functionality. Nano titania-silica-lanthanum phosphate sol with an average particle size of 59 nm has been synthesized using an all aqueous sol-gel route starting from titanyl sulphate which was further used for the development of photocatalytically active nanotitania composite coatings on ceramic glazed substrate by spray coating technique. The coated substrates were annealed at 700 °C. The photoactivity of the prepared nanocomposite coating was found to increase by the incorporation of silica in the titania matrix. The enhanced photoactivity and non-wettability was due to the synergistic effect of mixed oxide additives. Thus, by combining the inherent properties of the components, a novel nanocomposite material exhibiting self-cleaning ability and high photocatalytic efficiency was synthesized. The prepared titania-silica-lanthanum phosphate nanocomposite calcined at 700 °C has given a BET surface area of 244 m²/g and an average grain size of 5.6 nm was observed from TEM. SEM images of the coated surface showed clear evidence of the nanocoating. The present approach for the synthesis of novel and functional composite coating over tile substrate can be extended further to other substrates, leading to a variety of applications useful to society.