The mechanism of H 2 dissociation and adsorption on Mn-modified Ni(111) surface: A density functional theory-based investigation

Abstract

The mechanism of H 2 dissociative adsorption on Mn-modified Ni(111) surface is investigated and explained using spin-polarized density functional theory (DFT). Potential energy surface (PES) is used to determine the efficient reaction pathway of H 2 on the surface. The dissociative adsorption of H 2 in the hollow sites with its center-of-mass (CM) positioned on top of Ni atom has low activation barrier. This is lower compared if its CM is on top of the Mn atom. The difference in the reactivity of H 2 with Ni and Mn as the CM is corroborated by the positions of the bonding and antibonding orbitals of H 2 as it approaches the surface which is verified from local density of states (LDOS). The greater density of states in the region around the Fermi level of the d zz, d xz, and d yz orbitals of the Ni atom explains the low activation barrier obtained for the dissociation of H 2 on top of the Ni atom in the Mn-modified Ni(111) surface.