A THEORETICAL-STUDY OF CARBON CHEMISORPTION ON NI(111) AND CO(0001) SURFACES

Atomic carbon is a key intermediate which interacts with the surface d uring hydrocarbon growth reactions over transition metal surfaces. How ever, experimental data are scarce, available only for carbon-metal bi nding energies on nickel(111) and (100) single crystal surfaces. There fore, to deepen our understanding of the chemisorption of carbon and t o quantify its role in the catalytic formation of hydrocarbons, we hav e calculated the binding energy of atomic carbon on Ni(111) and Co(000 1) surfaces using density-functional theory within the generalized gra dient approximation and the full-potential linear augmented planewave (FP-LAPW) method. The results presented are in excellent agreement wit h known experimental values and substantially expand the database of g eometric and energetic parameters describing adsorption of carbon on n ickel and cobalt surfaces as a function of surface coverage and the ad sorption site. The surface coverage dependence of the binding energy w ill be discussed and is used to interpret the tendency of the differen t surfaces toward molecular weight growth and their intrinsic reactivi ties. (C) 1998 Academic Press.