Comparative study of textural, structural and catalytic properties of xerogels and aerogels CeO2–TiO2 mixed oxides

CeO2–TiO2 mixed oxides (aerogels and xerogels) were synthesized via sol–gel method with a Ce/Ti molar ratio of 1/5. Characterization of the samples was accomplished by N2 physisorption, XRD, UV–Vis and FTIR spectroscopy, H2-TPR and TEM. Textural analysis reveals that aerogels showed a pronounced specific surface area. XRD analysis confirmed that xerogels were amorphous whereas aerogels stabilized TiO2 anatase phase even at high calcination temperature. Furthermore, the addition of CeO2 to the TiO2 samples decreases the anatase–rutile phase transformation and the band gap energy when compared with pure TiO2. These mixed oxides were used as supports for Ru catalysts in the catalytic wet air oxidation of p-hydroxybenzoic acid at 140 °C and 50 bar of air. The Ru catalyst supported on aerogel exhibits good catalytic activity due to the high Ru dispersion.