The adsorption energies of intermediates in CO methanation on the modified Ni 3 Al(111) surface and the Ni(111) surface are calculated using density functional theory. A microkinetic analysis based on the calculated adsorption energies is performed to explain the different kinetics of CO methanation catalyzed by Ni 3 Al and Ni powders. The electronic structures of different atoms on the modified Ni 3 Al surface are also presented, and correlate well with the adsorption energies and geometries.