Effect of active site and charge transfer on methane dehydrogenation over different Co doped Ni surfaces by density functional theory

Abstract

To uncover the effects and the underlying mechanisms of Co content on CH4 dehydrogenation over Ni–Co bimetal catalyst, the CH4 successive dehydrogenation process over Ni (111) and different Co doped Ni (111) surface has been systematically studied via DFT calculation. Active sites and electronic properties have been obtained. CH4 physically located at the top site of Ni or Co, while other CHx species preferably occupied the threefold site. Besides, the charge transferred from surface to absorbates and the p-band center of absorbates could well describe the adsorption strength of CHx and the activation barrier of CH dehydrogenation on different surfaces. More importantly, the addition of small Co could improve the resistance to carbon deposition by weakening the adsorption of C, suppressing the activity of CH4 dehydrogenation and promoting C hydrogenation process.