Nanocast ordered Mesoporous Ceria as Support for Highly Active Gold Catalysts for Toluene total Oxidation

Abstract

AuCeO2 catalysts were synthesized using ceria prepared by the nanocasting pathway using the mesoporous SBA 15 silica as structure template and cerium nitrate as the CeO2 precursor via a solid –liquid route. These catalysts have been characterised by means: elemental analysis, H2- TPR, X-ray powder diffraction (XRD), BET surface area, diffuse reflectance ultra-violet visible spectroscopy (DR/UV-vis). Catalytic oxidation of toluene was investigated on gold/cerium oxide catalysts prepared by deposition-precipitation with several loading of gold (1wt%, 2wt%, and 4wt %). The presence of gold has been found to enhance the activity of cerium oxide to the deep oxidation of toluene, the degree of this effect depending on the gold loading. The activity for toluene deep oxidation of the AuCeO2 samples follows the order: 2wt%AuCeO2 ~ 1wt%AuCeO2 > 4wt%AuCeO2. The AuCeO2 catalysts are active at low temperature and selective for CO2 and H2O. The 1wt% AuCeO2 catalyst exhibits a long-term stability. The results we obtained point out that the catalytic activity of the gold/mesoporous ceria system towards the deep oxidation of toluene depends on the gold particle size and the amount of reducible surface oxygen species.