Reaction Kinetics of Ethylene Glycol Reforming over Platinum in the Vapor versus Aqueous Phases

First-principles, periodic, density functional theory (DFT) calculations are carried out on Pt(111) to investigate the structure and energetics of dehydrogenated ethylene glycol species and transition states for the cleavage of C−H/O−H and C−C bonds. Additionally, reaction kinetics studies are carried out for the vapor phase reforming of ethylene glycol (C 2 H 6 O 2 ) over Pt/Al 2 O 3 at various temperatures, pressures, and feed concentrations. These results are compared to data for aqueous phase reforming of ethylene glycol on this Pt catalyst, as reported in a previous publication (Shabaker, J. W.; et al. J. Catal. 2003, 215, 344). Microkinetic models were developed to describe the reaction kinetics data obtained for both the vapor-phase and aqueous-phase reforming processes. The results suggest that C−C bond scission in ethylene glycol occurs at an intermediate value of x (3 or 4) in C 2 H x O 2 . It is also found that similar values of kinetic parameters can be used to describe the vapor and aqueous phase reforming data, suggesting that the vapor phase chemistry of this reaction over platinum is similar to that in the aqueous phase over platinum.