Sorbitol transformation into biofuels over bimetallic platinum based catalysts supported on SiO2-Al2O3 – Effect of the nature of the second metal

• Published in: Fuel processing technology Vol. 177; pp. 159 - 169
• Main Authors: Messou, Davina, Vivier, Laurence, Especel, Catherine
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2018; Elsevier Science Ltd; Elsevier
• Subjects: Aluminum oxide; Ammonia; Aqueous solutions; Bimetallic catalysts; Bimetals; Biofuels; Catalysis; Catalysts; Chemical Sciences; Chemisorption; Cyclohexane; Dehydrogenation; Hydrogenolysis; Impregnation; Liquid fuels; Liquid phases; Nuclear fuels; Organic chemistry; Palladium; Platinum; Rhenium; Silicon dioxide; Sorbitol; Synergistic effect; Transformations; Vapor phases; Sorbitol; Bimetallic catalysts; Rhenium; Biofuels; Platinum
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2018.04.030

Sorbitol hydrogenolysis in aqueous medium was carried out over Pt based catalysts supported on SiO2-Al2O3 and modified by a second metal (Re, Ir, Rh and Pd). The catalysts were synthetized by two preparation methods, co-impregnation and successive impregnations. The metallic properties of these catalysts were characterized by transmission electron microscopy and X-ray diffraction, H2 chemisorption, temperature programmed reduction and by the model reaction in gas phase of cyclohexane dehydrogenation. The acidic properties were characterized by ammonia thermodesorption and by the model reaction in gas phase of 3,3-dimethyl-1-butene. The catalytic performances were compared to those of corresponding monometallic catalysts under hydrothermal conditions, in a batch reactor at 240 °C under 60 bar H2 pressure. The main products were poly- and mono‑oxygenated compounds in liquid phase and hydrocarbons in gaseous phase. Among the studied modifiers, Re allowed to promote the catalytic performances of Pt leading to a synergistic effect for the transformation of sorbitol into liquid fuels (hexane). The highest efficiency of the Re-Pt/SiO2-Al2O3 catalyst prepared by co-impregnation was explained by an optimal balance between the acidic and metallic functions constituted of bimetallic particles of small size dispersed on the acidic support. [Display omitted] •Bimetallic catalysts were prepared for the sorbitol hydrodeoxygenation to biofuels.•A Pt/SiO2-Al2O3 monometallic catalyst was modified by addition of various metals.•Re additive leads to a bimetallic interaction with charge transfer from Ru to Pt.•The co-impregnated Re-Pt catalyst induces a synergistic effect for hexane formation.•Its surface state exhibits an optimal repartition of the metallic and acidic sites.