DFT study of methanol adsorption on PtCo(111)

Abstract

Methanol adsorption on PtCo(111) surface at low coverage is studied using Density Functional Theory (DFT) calculations without and with van der Waals corrections. We investigated the PtCo FCT alloy surface with a uniform distribution. The most favorable site for CH3OH adsorption is on top of a Co atom, with an adsorption energy of −0.92 eV. Methanol attachs to the surface by the O atom, with a distance of 2.24 Å. The molecule presents a small distortion after adsorption. The C–O–Co bond angle is 142°. The C–H bonds are strengthened whereas the C–O and O–H bonds are weakened. A charge transfer from C atom to O atom occurs upon adsorption, and then further transfer occurs to the Co atom on the surface. The calculated vibrational frequencies for adsorbed methanol present a red-shift displacement compared to gas-phase, confirming the adsorption process.