Upgrading furfural to bio-fuels using supported molybdenum carbides: study of the support effect

Materials exhibiting different textural and surface properties (SiO₂, TiO₂, ZrO₂ and ZSM-5) were investigated as supports for Mo carbides in the upgrading of furfural (FF) in liquid phase to produce 2-methylfuran (2MF). The state of the catalysts after carburization, passivation, and reactivation under a hydrogen atmosphere was investigated by XAS analysis. The effect of the supports was observed in the first step of the reaction, i.e., the hydrogenation of FF to furfuryl acid and related to Lewis acidic and basic sites. The nature of the supports was also relevant to the final state of the Mo carbides after carburization, passivation, and reactivation. The comparison of the materials showed that Mo₂C/SiO₂ was the least decarburized catalyst after reactivation, and the most active in converting furfural, while the Mo₂C/TiO₂ system presented smaller carbide particles after carburization and more disorganized particles after reactivation. Mo carbide supported on SiO₂ and on TiO₂ were found to be suitable catalysts for producing a mixture containing 2-methylfuran and C₁₀ compounds with potential application as biofuel.