New Insights in Single-Step Hydrodeoxygenation of Bioglycerol to Propylene by Coupling Rational Catalyst Design with Systematic Analysis

This work proposes rationalized developments to achieve relevant breakthroughs in single-step bioglycerol-to-propylene. It discusses how to successfully get high loadings of highly reactive sub-2 nm Mo particles onto silicas. Dispersed MoOx feature propylene yield that range from 84.1% to 65.6% at space-velocity 1.7h -1 and pressure 50 bar, but they become less hydrogenating when increasing space-velocity or lowering H2-pressure. In turn, β-Mo2C and η-MoC feature, at steady-state, unprecedent 153.1h-1 and 98.2h-1 , respectively. Coupling in-situ XPS and kinetic data reveal that Mo5+, Mo3+ and Mo2+-C species play a critical role in the HDO events. Glycerol-to-propylene progresses over MoOx via successive Mo5+/Mo6+ and Mo3+/Mo4+ cycles, while over Mo carbides, it occurs mostly on carbidic-oxycarbide surface. The re-oxidation of Moδ+ represses HDO events, which is attributed to the oxygen accumulation. This approach offers a potential versatility to serve as a base for building new design schemes destined to HDO of complex biomolecules