Molybdenum doped carbon aerogels with catalytic potential
Résumé
High surface area carbon aerogels with increasing molybdenum content were obtained with the carbonization of resorcinol-formaldehyde polymer aerogel after incipient wetness impregnation (IWI). The Mo(VI) form of the impregnant was converted into different molybdenum species during the heat treatment, resulting in samples with substantially different surface and bulk compositions. The samples were tested in the hydroconversion reaction of acetic acid, a model biomass. The reaction pathways and the product distribution were governed by the accessibility of the carbon surface as well as by the amount and form of Mo. The highest selectivity for ethanol was 16 % when 85 % of the acetic acid was converted. Post-catalyst analysis of the aerogels revealed that their morphology and chemistry changed substantially during the redox processes. The products of each of the three potential pathways (hydrogenolysis, ketonization and consecutive reduction) oxidized the surface even in the reductive hydrogen flow.