Influence of calcination temperatures on the anatase and rutile mixed phase composition and photocatalytic activity of the carbon doped mesoporous TiO2

Utilizing dicyandiamide as carbon source, the carbon doped mesoporous TiO2 (C–TiO2) with high photocatalytic activity was synthesized by sol-gel method, and the influence of calcination temperatures on the phase composition and photocatalytic properties of C–TiO2 photocatalyst were investigated. The XRD analysis shows carbon dopant in TiO2 can change the phase structure of the TiO2 and retard the TiO2 phase transformation from anatase to rutile. The N2 adsorption-desorption isotherms further inform the presence of mesoporous structure and XPS analysis clearly demonstrates that carbon atoms are successfully incorporated into the TiO2 crystals, which could cause a long-tail absorption in the visible-light region. Methylene blue was used to evaluate the photocatalytic activity of C–TiO2 under a xenon lamp irradiation. Compared with TiO2(550), the photocatalytic activity of as-prepared C–TiO2 is greatly improved, and C–TiO2 photocatalyst synthesized at 550 °C exhibits the most excellent photocatalytic performance due to its appropriate TiO2 phase composition of 74.7 wt% anatase and 25.3 wt% rutile, a larger specific surface area and effectively separating of e− and h+.