One-Step “Green” Synthetic Approach for Mesoporous C-Doped Titanium Dioxide with Efficient Visible Light Photocatalytic Activity

Mesoporous C-doped TiO2 nanomaterials with anatase phase are synthesized by a one-step “green” synthetic approach with low-cost inorganic Ti(SO4)2 and glucose as precursors for the first time. This facile method avoids treatment at high temperature, use of expensive or unstable precursors, and production of undesirable byproducts in the synthesis process. The physicochemical properties of as-prepared samples are characterized in detail by X-ray diffraction (XRD), Raman spectroscopy (Raman), N2 adsorption−desorption isotherms, transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG), UV−vis diffuse reflectance spectroscopy (UV−vis DRS), and photoluminescence (PL). The results indicate that oxygen sites in the TiO2 lattice are substituted by carbon atoms and an O−Ti−C bond is formed. The observed new electronic states above the valence band edge are directly responsible for the electronic origin of the band gap narrowing and visible light photoactivity of the C-doped TiO2. Furthermore, the possible formation mechanism of mesoporous C-doped TiO2 is also discussed. The as-prepared C-doped TiO2 exhibits excellent visible light photocatalytic activity in degradation of toluene in the gas phase compared with that of commercial TiO2 photocatalyst (P25) and C-doped TiO2 prepared by the solid state method. The efficient activity can be attributed to the large surface area and pore volume. Our novel synthesis approach is energy-efficient and environmentally friendly, which can provide an effective approach for industrial applications owing to its low cost and easy scaling up.