Gold stabilized aqueous sols immobilized on mesoporous CeO2-Al2O3 as catalysts for the preferential oxidation of carbon monoxide

Nanostructured Au/Al2O3-CeO2 catalysts with a low content of precious metal (0.9%wt.) were prepared immobilizing two different stabilized Au sols on a high surface area Al2O3-CeO2 mixed oxide with a uniform pore size distribution, synthesized by a one-pot methodology. The samples were characterized by elemental analysis, N2 physisorption, XRPD, TEM and 27Al-MAS NMR techniques. The catalytic activity of the two samples in the preferential oxidation of CO in excess of H2 (CO-PROX) was comparatively evaluated in the 35-110°C temperature range. The Au-THPS/AlCe20 sample, prepared immobilizing a sol obtained reducing an aqueous solution of gold tetrachloroaurate salt with bis[tetrakis(hydroxymethyl)phosphonium sulfate], resulted very active and selective at low temperatures and its catalytic activity was correlated with the structural characteristics of the metal particles and of the ordered mesoporous support.