Surface characteristics of hydrous silica-coated TiO2 particles

The surface characteristics of hydrous silica-coated TiO2 particles are experimentally studied. Different analytical techniques were used to characterize the Si oxide coatings on TiO2 particles. The high-resolution transmission electron microscope (HRTEM), ζ-potential analyzer and X-ray photoelectron spectroscope (XPS) analyses show that hydrous silica is continuously coated on the surface of TiO2 particles. From the chemical shift of binding energy of O 1s and Ti2p3/2 on coated particles and FTIR analyses of absorption band, it is inferred that Si oxide in the coating film is combined onto TiO2 particle surface through chemical bond of Ti–O–Si. The electrokinetic behavior of TiO2 particles can be modified significantly by dense film coating.