Rationalizing the mechanism of ethanol dehydrogenation on Pt/C

Using ab initio calculations we investigate the mechanism of ethanol dehydrogenation on Pt catalyst. The calculated adsorption energies indicate CH4 and H2 as final products, which is consistent with experimental observations. A detailed analysis of reaction pathways with measured and computed data indicates partial desorption of CH3CHO and CO, with both processes occurring simultaneously and rapidly. We found that the latter is not preceded by the formation of surface CO species and results from: (1) a kinetic process due to the high activation barrier for C-C bond breaking during the ethanol degradation process and (2) an initial CO configuration that favors its desorption. Besides deciphering the new mechanism, our calculations validate previously suggested degradation pathways and show that the combination of experiment and simulations is an effective approach to improve our understanding of catalytic reactions.