Understanding the influence of rare earth yttrium on surface characterizations of orthorhombic α-Mo_2C(023) surface: A first-principle calculation approach

摘要

A detailed theoretical study on clean and Y-doped orthorhombic ?-Mo2C(023) surface has been investigated by means of the first-principles calculations. The calculated surface energies of ?-Mo2C(023) surface indicated that the catalytic activity ?-Mo2C(023) surface decrease gradually with the increase of Mo chemical potential. It is demonstrated from the doped formation energy that the Y atom prefers to replace the Mo2 site of ?-Mo2C(023) surface and the doped formation energy of YM2/?-Mo2C(023) surface is lowest. The detailed work function calculations reveal that the doping of Y atom can facilitate the escaping of the electron from the ?-Mo2C(023) surface. According to the calculated results of electron density differences and density of state, it was found that the Y doping has a strongly influence on the electronic structures of ?-Mo2C(023) surface. Hirshfeld charge analysis found that the more charges are transferred from Y atom to the adjacent C atoms compared to Mo atoms.