The adsorption and dissociation of methane on cobalt surfaces: thermochemistry and reaction barriers

The adsorption and dissociation of methane (CH4) on a variety of cobalt (Co) surfaces have been assessed using density functional theory. The adsorption of CHx (x = 0-4) and H species, as well as the sequential dissociation of CH4 on Co(111), (100) and (110) surfaces, have been studied. Using the calculated adsorption energies, the preferred adsorption sites for CHx (x = 0-4) and H species on different Co surfaces have first been located, and then the stable co-adsorption configurations of CHx and H (x = 0-3) on these surfaces obtained. In addition the mechanism for the sequential dissociation of CH4 on Co surfaces has been investigated and compared in terms of the thermodynamics and kinetics involved. Our results suggest that Co(100) is the preferred surface for CH4 dissociation, both thermodynamically and kinetically, rather than (111) and (110) surfaces.