Optical and structural properties of TiO2 nanopowders with Ce/Sn doping at various calcination temperature and time

In this paper, the influence of calcination temperature and time has been investigated on the structural, morphological, optical, and photo-catalytic properties of Sn/Ce co-doped TiO2 nano-powders prepared via sol-gel process. They were calcined at the temperatures in the range of 475-975 degrees C for 1 and 2 h. The photocatalytic ability of TiO2 powders was evaluated by means of methylene blue degradation experiments conducted under the irradiation of simulated solar light. The X-ray diffraction results showed that the tensile strain in the host lattice was present. The comparison with undoped and Sn or Ce-doped TiO2, co-doped TiO2 shows an obviously higher catalytic activity under visible light irradiation. The absorbance spectrum of Ce and Sn co-doped TiO2 exhibited significant red-shift to visible region. The red-shift is caused by the appearance of a new electronic state in the middle of the TiO2 band-gap. FESEM images show the formation of doped TiO2 nanoparticles with small size in structure and spherical in shape. The FTIR spectra exhibited peaks corresponding to the anatase and rutile structure phases of TiO2.