A theoretical study of CHx chemisorption on the Ru(0001) surface

The thermodynamics of methane decomposition on the ruthenium (0001) surface has been investigated with ab initio periodic calculations for coverages of 25% and 11%. All surface intermediates are more stable than the gas-phase methane even if the last step of the decomposition path (CH→C+H) is highly endothermic. Amongst all of the surface species, CH appears to be the most stable, in agreement with experiments. All of the surface species (CHx=3,0 and H) adsorb on three-fold sites. Short-range lateral interactions between CHx=3,0 and H are also considered and are found to be mostly repulsive.