The catalytic activity of PtnCum (n+m=3, m≠3) clusters for methanol dehydrogenation to CO

Abstract

Based on the density functional theory (DFT), the geometric for the reactants, intermediates, transition states and dehydrogenation products have been optimized. The energy diagrams are drawn out along both the O-adsorption path and H-adsorption path, and the C-H bond scission pathway is energetically more favorable than the O-H bond scission pathway. By calculation, the Pt is the active site in the whole reaction processes, and the barrier energy of the rate-determining step is 11.09 kcal/mol by Pt: Cu=2: 1 which is lower than that of Pt 3 and PtCu 2 . Importantly, it is shown that the complete dehydrogenation product of methanol, CO, can more easily dissociate from PtCu 2 cluster than from Pt 3 cluster. Therefore, Cu doping can promote the catalytic activity of Pt in a certain extent.