Influence of activated carbon surface chemistry on the activity of Au/AC catalysts in glycerol oxidation

The main goal of this work is the study of the relationship between the surface chemical characteristics of activated carbon and the performance of the respective gold-supported catalysts in the oxidation of glycerol. For that purpose, a set of modified activated carbons with different levels of oxygenated functional groups on the surface, but with no major differences in their textural parameters, was prepared. A strong effect of the activated carbon surface chemistry on the catalytic activity was observed. Gold particles with similar average sizes resulted in different performances, being the surface oxygenated acid groups particularly prejudicial for the catalytic activity. Basic oxygen-free supports characterized by a high density of free π-electrons lead to more active catalysts; the observation was tentatively explained on the basis of a recent proposed mechanism by considering the capability to promote electron mobility. However, the presence of oxygenated groups on the support does not influence significantly the selectivities.