Formation of CO2 and Ethane from Propionyl over Platinum: A Density Functional Theory Study

The conversion of propionyl, the most stable dehydrogenation product of 1-propanol on flat and stepped Pt(111) surfaces is explored computationally as a model for the transformation of alcohols on Pt to CO 2 and hydrocarbons. We studied a reaction network in which dehydrogenation steps or hydroxyl insertion may precede the desired C–C cleavage, via either decarboxylation or decarbonylation. In the latter case, CO 2 will be obtained via a subsequent water-gas-shift reaction. On a flat surface, the decarbonylation pathway with the highest barrier of 91 kJ mol –1 was calculated to be preferred, as the decarboxylation reactions are inaccessible because of high barriers of the preceding dehydrogenations, 129 kJ mol –1, or the C–C bond scission itself, 204 kJ mol –1 . At step defects the highest barrier for decarboxylation was determined to be notably lower, at 86 kJ mol –1, making this pathway competitive for C–C scission.