Influence of the nature of the support on the catalytic properties of Pt-based catalysts for hydrogenolysis of glycerol

A series of platinum catalysts supported over various supports (Al2O3, Al2O3-SiO2 and TiO2) were prepared and characterized by X-ray diffraction, N-2 sorption, H-2 chemisorption, temperature programmed reduction, FTIR of adsorbed pyridine, 3,3-dimethyl-1-butene isomerization and cyclohexane dehydrogenation. These catalysts were evaluated for aqueous-phase process (APP) of glycerol at 210 degrees C, under N-2 or H-2 atmosphere (60 bar as total pressure). Among the tested catalysts, Pt/TiO2 was the most active and the most selective toward C-3 products (propanediols, propanol) which can be further valorized into chemicals. TiO2 was identified as the support leading to the most stable Pt metallic phase, catalytic phase on which the hydrogenation/dehydrogenation reactions take place. The presence of acidic sites brought by the oxide support is necessary for the dehydration reactions (i.e. for C-O cleavages), but a too high quantity of these sites can promote the C C bond cleavages via an acidic cracking mechanism. Among the various supported Pt-based catalysts studied in this work, Pt/TiO2 sample appears to be the most promising system for the transformation of polyol in aqueous phase. (C) 2012 Elsevier B.V. All rights reserved.