Au/Fe2O3 Nanocatalysts for Toluene Oxidation as Model VOCs

Abstract

Au/ Fe2O3 catalysts were synthesized using iron oxide prepared by the nanocasting pathway using the mesoporous SBA-15 silica as structure template and iron nitrate as the Fe2O3 precursor via a solid–liquid route. These catalysts have been characterised by means: H2-TPR, X-ray powder diffraction (XRD), BET surface area. The gold particles sizes were investi gated by high resolution transmission electron microscopy (HRTEM). Catalytic oxidation of toluene was investigated on gold/iron oxide catalysts prepared by deposition-precipitation with different loading of gold (1 wt%, 2 wt%, and 4 wt%). The presence of gold has been found to enhance the activity of iron oxide towards the deep oxidation of toluene, the extent of this effect depending on the gold loading. The activity for toluene total oxidation of the Au/Fe2O3 samples follows this order: 2 wt% Au/Fe2O3 > 4 wt%Au/Fe2O3 > 1 wt%Au/Fe2O3. The Au/Fe2O3 catalysts are active at low temperature and selective for CO2 and H2O. The results we obtained point out that the catalytic activity of the gold/mesoporous iron system towards the deep oxidation of toluene depends on the gold particle size and/or the gold oxidation state and the reducibility of Au2O3 to AuO