The Si/P–TiO2 nanoparticles, with a molar ratio [Si + P]/[Si/P–TiO2] = 0.03, were synthesized using a sol–gel method. The effects of relative ratios of dopants (i.e., R ≡ [P]/([Si + P]) and calcination temperatures on phase transformation, grain growth, and photocatalytic activity of the gel-derived Si/P–TiO2 were examined. While the Si–TiO2 (i.e., R = 0) had its anatase structure stabilize at 700 °C for 2 h, the Si/P–TiO2 (i.e., 0.33 ≤ R < 1) and P–TiO2 (i.e., R = 1) were able to preserve the anatase-TiO2 at temperature as high as 900 °C. Although at 900 °C the phosphorus elements in Si/P–TiO2 nanoparticles were partly excluded to the particles’ surface and tended to fuse the adjacent particles together, which may lead to a large reduction in their specific surface areas and photocatalytic activities, the Si/P–TiO2 with high silicon contents, such as the particles of R = 0.5 and 0.33, were still composed of loosely packed nanoparticles and showed good photocatalytic ability. In whole, the Si/P–TiO2 nanoparticles of R = 0.5 calcined at 600–900 °C gave the superior performance in photocatalytic activity, under both 365-nm UV light and white light irradiation.
Journal of Alloys and Compounds 492(1-2), pp.695-700