| Abstract: | Sol-gel TiO2-CeO2 materials were synthesized at pH=3 employing HNO3 as hydrolysis agent. Gels were thermally treated at 473, 673, 873, and 1073 K, respectively. Morphologies of the final substrates were studied via N2 sorption, XRD and TEM. N2 isotherms indicated a steady porosity in TiO2-CeO2 samples treated up to 873 K. Adsorption-desorption isotherms and TEM micrographs were used to perform fractal analyses of annealed samples. A dominant anatase phase was detected by XRD between 473 and 873 K while a rutile phase was evident at 1073 K. The presence of cerium conferred an increased thermal stability to the TiO2 materials against particle sintering and pore collapse. The structure of cerium-doped anatase lattice was visualized through crystal simulation to investigate the possible substitution of Ti4+ by Ce+4 ions. This effect and the progressive segregation of CeO2 crystals with temperature on the surface of TiO2 grains lead to substrates of assorted morphologies. |
