Photocatalyst Nanocomposite Hybrid Coatings Based on TiO2-SiO2 Core/Shell Nanoparticles: Preparation and Investigation of Weathering and Corrosion Resistance

Inorganic-organic hybrid coatings with TiO2-SiO2 core/shell nanoparticles were prepared in order to develop the self-cleaning and corrosion resistant coatings. As proved in XRD test, the anatase TiO2 nanoparticles were prepared by sol-gel method in two different thermal conditions namely high temperature and low temperature process. The size and the shape of the particles in amorphous TiO2 sol and the thickness of SiO2 layer on the anatase nanoparticles revealed a core/shell structure by transmission electron microscopy. The photocatalytic activities of the coatings using the prepared TiO2-SiO2 nanoparticles were investigated via the decomposition of methylene blue (MB) under UV-radiation and compared with those samples prepared using commercial TiO2, i.e. P25 Degussa. It was found that the photocatalytic activity of the coatings was significantly attributed to the crystallinity and the particle size of anatase nanoparticles. To find out the effect of photocatalytic activity on the corrosion resistance, the nanocomposites coatings were exposed under UV for 1080 h. The Tafel curves of the samples showed lower corrosion resistance for the coatings of higher photocatalytic activity. J. Color Sci. Tech. 7(2013), 151-164©. Institute for Color Science and Technology.