A Density Functional Investigation on C Atom Adsorbed on Ni (111) Surface in the Steam Reforming of Acetic Acid

The adsorption modes of C on the clean Ni (111) surface had been investigated by first principles Density Functional Theory (DFT) within a periodic slab model and the generalized gradient approximation. The threefold hep and fee hollow sites on Ni (111) surface were preferred to be adsorbed strongly by the C atom with chemisorptions energy of-6.89 eV and -6.81 eV. The calculated binding energies had been compared with the previous experimental and theoretical results and good agreement was found. The local density of states (LDOS) showed that the formation of adsorption bonding was mainly due to the mixing between the carbon 2p and Ni 3d orbitals. The analysis of charge density difference and Mulliken population suggested that there were a net charge flow of electrons from the Ni surface to C atom induced by the adsorption.