Density functional periodic study of the dehydrogenation of methane on Pd (111) surface

The adsorption and dehydrogenation mechanism of CH4 on Pd (1 1 1) surface was studied using density functional theory (DFT) together with periodic slab models. According to the optimized structural and energetic properties, it was found that CH3 prefers to adsorb on the top sites of the Pd metal surface. Whereas CH2, CH, and H prefer to adsorb on the fcc sites, and C prefers to adsorb on the hcp sites. In addition, this work identified the optimum configurations for the stable co-adsorption configurations of CH, and H. Finally, four transition states were found for analyzing the mechanism of dehydrogenation of CH4. The results show that the dehydrogenation of CH moiety is relatively difficult and the dehydrogenation of CH3 is the rate-determining step in the overall reaction. (C) 2013 Elsevier B.V. All rights reserved.