چکیده (انگلیسی):

We have investigated the CH4 adsorption and the C-H bond breaking activation on the metal ad-atom of M@M (111) (M=Ni, Pd, Pt, Cu, Ag, Au) and M@M (111)/H (covered by hydrogen atoms) 3 and 1-layer surfaces (4-type surfaces) using spin-polarized Density Functional Theory (DFT). We find that the adsorption energies of methane are related to the d-band center of metal ad-atoms. In particular, the distances between CH4 and Ni, Pd, and Pt ad-atoms of 4-type surfaces are shortened and the adsorption energies of CH4 on metal ad-atoms are stronger than the perfect surfaces because the d-band center of metal ad-atoms are close to the Fermi level. Furthermore, we have investigated the activation barrier energies of C-H bond breaking of CH4 on Ni, Pt, and Ag ad-atoms of 4-type surfaces because Pt ad-atom exhibits stronger adsorption energy of CH4, Ag ad-atom exhibits weaker ones, and Ni utilizes for the steam reforming reaction. We find that Ni and Pt ad-atoms show lower activation barrier energies, and they are related to the CH4 adsorption energies as well as the d-band centers.