Ethane Adsorption and Decomposition on Ni(111) Surface

A possible decomposition mechanismfor ethane on Ni(111) surface was investigated using first-principles density functional theory (DFT) and a self-consistent periodic calculation. The transition states were determined using complete linear synchronous transit and quadratic synchronous transit (LST/QST) methods. All the species involved in this process had four possible adsorption sites (top, fcc, hcp, and bridge) on the Ni(111) surface and all these were fully optimized to obtain their equilibrium geometries and electronic structures. The corresponding adsorption energies and Mulliken charge analyses of these species were predicted and compared. Favorable adsorption sites on the Ni(111) surface for these species were found. In the C—C bond activation pathway, the energy barrier of the rate-limiting step was 257.9 kJ·mol-1. However, the energy barrier of the rate-limiting step was only 159.8 kJ·mol-1 for the C—H bond activation pathway, which suggested that the C—H bond activation pathway would be preferred. As a result, the main products are C2H4 and H2.