Synthesis of visible-light active TiO2 photocatalyst with Pt-modification: Role of TiO2 substrate for high photocatalytic activity

Nano-sized TiO2 photocatalysts were prepared by hydrolysis of TiCl4 followed by calcination at different temperatures. X-ray diffraction (XRD) measurements revealed that all TiO2 powders crystallized in rutile even before calcination. The photocatalytic activity of the raw TiO2 powder clearly decreased with increasing calcination temperature. Pt-modification of the surface of TiO2 increased photocatalytic activity under visible-light irradiation, depending on the calcination temperature. Maximal photocatalytic activity was obtained at calcination temperatures of 300–450 °C, which was correlated with the light absorption properties of the Pt complex on TiO2 nano-particles. It was found that TiO2 surface structure plays an important role in the formation of TiOPt bonds, resulting in a large visible-light absorbance and high photocatalytic activity under visible-light irradiation.