An Efficient Reaction Pathway Search Method Applied to the Decomposition of Glycerol on Platinum

First-principles-calculation-based understanding of the reaction mechanisms of processing biomass derivatives is currently lacking due to the cost involved in performing computations of multireaction mechanisms of large molecules. We combine semiempirical methods (group additivity and Bronsted-Evans-Polanyi (BEP) linear free energy relationships) and density function theory (DFT) calculations to provide an efficient search method of key intermediates and reactions and point out the most likely reaction pathways for conversion of glycerol to synthesis gas on Pt(111). The following pathway, C3H8O3 -> CHOHCHOHCH2OH -> CHOHCHOHCHOH -> CHOHCOHCHOH -> COHCOHCHOH -> COCOHCHOH -> CO + COHCHOH, is identified as the most favorable one and a highly dehydrogenated species (COCOHCHOH) is a key intermediate for C-C bond cleavage. The (over-)functionalization of biomass changes the nature of the rate-controlling step to dehydrogenation compared to C-C scission in hydrocarbons and monols. Our results indicate that for biomass reforming, catalysts with high initial-step dehydrogenation activity should be developed.