Titanium dioxide (TiO2) has attracted significant attention because of its photocatalytic and UV absorbance properties. However, despite the good UV-shielding property of TiO2, it is not suitable for use in outdoor UV-shielding protective films because of its strong photocatalytic behavior when absorbing UV radiation. Here, we describe a TiO2@SiO2 core shell structure with uniform and thin SiO2 layer; the SiO2 shell suppresses TiO2 photocatalytic activity and improves the wettability of the TiO2. TiO2@SiO2 nanoparticles were characterized by TEM, FT-IR, XPS, and VB-XPS. A uniform, thin SiO2 shell suppressed the photocatalytic activity of the TiO2 core by broadening the band gap because of the existence of Ti-O-Si chemical bonds at the interface of TiO2 and SiO2. Moreover, the increase in wettability of the TiO2@SiO2-coated films observed was a permanent property and did not require UV activation.

Keywords: Titanium dioxide, SiO2 shell, Photocatalytic activity, Hydrophilicity