Preparation of C Doped TiO<sub>2</sub> Photocatalysts and their Photocatalytic Reduction of Carbon Dioxide

TiO 2 doped with C was obtained by way of immersion and calcinations method by using citric acid (CA) as dopant material.，and characterized by using XPS、XRD, UV-Vis, FT-IR and SPS. The results of analysis and characterization showed that C substituted partial Ti atoms in the lattice of TiO 2 and formed Ti-O-C structure. The photocatalytic properties of C-TiO 2 photocatalysts had been evidently improved as a result of a noticeable shift to visible region and the enhancement of the charge separation efficiency. The doped carbon lowers the band gap and expends the absorption of visible light region. CO 2 was photocatalytically reduced to form HCOOH by the best C-TiO 2 -3/1-600 nanoparticles under the irradiation of the simulated daylight lamp. Methanoic acid yield may achieve 2633.98μmol/g-Cat when irradiation time is six hours.