Theoretical Study of the Adsorption of Bisulfate on Small Gold Clusters

Abstract

The results of density functional theory energy calculations of bisulfate adsorbed to gold atom clusters are presented and discussed. The gold atom clusters are used to model a gold(111) surface. These calculations involve the Becke three-parameter functional to approximate the exchange energy and the Lee, Yang, and Parr approximation to include the electronic correlation contribution. The structure and stability of the bisulfate ion at different adsorption sites on the gold surface are examined. The bisulfate in its tripod orientation is found to be the most stable configuration due to the direct interaction of each oxygen of the tripod with a gold atom of the surface. The binding of the bisulfate is predominantly electrostatic and is strongly dependent on the local charge of the gold up to second-nearest neighbors from the adsorption site. Additionally, the bisulfate prefers the face-centered cubic 3-fold hollow adsorption site directly above a hollow in the second layer and a gold atom in the third layer.