Silica coated titania nanoparticles were prepared on the basis of the hydrolysis of tetraethyl orthosilicate (TEOS) in aqueous ethanol solution with ammonia as catalyst. The various values of thickness of silica coating on titania nanoparticles were obtained by controlling the weight ratios of TEOS added to TiO2 particles in solutions. When the silica loading was 9.33 wt%, the amorphous silica coating was uniform and distinct on the titania nanoparticles and the coated nanoparticles exhibited much better UV absorbance performances. However, as the silica loading further increased to 25.19wt%, the UV absorbance performances of silica/titania nanoparticles decreased. With the increase of silica loading in coated nanoparticles, the photocatalytic activity decreased.

Silica coated titania nanoparticles were prepared on the basis of the hydrolysis of tetraethyl orthosilicate (TEOS) in aqueous ethanol solution with ammonia as catalyst. The various values of thickness of silica coating on titania nanoparticles were obtained by controlling the weight ratios of TEOS added to TiO2 particles in solutions. When the silica loading was 9.33 wt%, the amorphous silica coating was uniform and distinct on the titania nanoparticles and the coated nanoparticles exhibited much better UV absorbance performances. However, as the silica loading further increased to 25.19wt%, the UV absorbance performances of silica/titania nanoparticles decreased. With the increase of silica loading in coated nanoparticles, the photocatalytic activity decreased.