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, N2 sorption, H2 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 °C, under N2 or H2 atmosphere (60 bar as total pressure). Among the tested catalysts, Pt/TiO2 was the most active and the most selective toward C3 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 CO cleavages), but a too high quantity of these sites can promote the CC 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.

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► Pt/Al2O3, Pt/Al2O3–SiO2 and Pt/TiO2 catalysts were synthesized and characterized.
► Their performances were evaluated for glycerol transformation in aqueous phase.
► Textural and structural modifications of catalysts occur during catalytic test.
► Metallic and acidic sites are involved in the selective CO cleavage of glycerol.
► Pt/TiO2 system is the most active and selective to C3 compounds (1,2-PD, propanol).