Density Functional Theory Study of Water Dissociative Chemisorption on the Fe₃O₄(111) Surface

Abstract

Water dissociative chemisorption on the Feoct-tet1-terminated Fe3O4(111) surface was studied using periodic density functional theory (DFT) at both low and high water coverage. The active sites and adsorption patterns were identified, and the dissociation pathways and energetics were calculated. It was found that water can undergo dissociative chemisorption to form a surface hydroxyl group and a H atom with a favorable thermochemical energy and a moderate activation barrier at low coverage. This reaction can be readily catalyzed by water molecules around the active sites. We found that direct breakup of the hydroxyl group into H and O adatoms on the surface is energetically difficult and higher water coverage has an only modest effect on catalyzing the reaction. Our results are consistent with the kinetic and isotope exchange experiments.