▎ 摘　　要

The stable geometries and adsorption behaviors of CHX (x=0, 1, 2, 3, 4) species on the single-atoms metal embedded graphene (M-graphene) are investigated by first-principles calculations. It is found that the adsorbed CHX species have the different stability on the M-graphene surfaces, and the adsorption energies of CHX species on the Al-graphene are smaller than those on the Au-graphene. Besides, the adsorption of CHX species can regulate the electronic structure and magnetic properties of M-graphene systems. Moreover, the diffusion pathways of CHX (x = 0-3) species and the conversion reactions between CHX (x = 1-4) species on the M-graphene are analyzed systematically. In the conversion reactions, the adsorbed C and CH species can be more easily converted into the CHX+2 species through the hydrogenation reactions, the broken M-H bond and the formation of new C-H bond need overcome the large energy barriers. These results give a clue for designing graphene-based anode materials with high activity and inhibiting carbon deposition. (C) 2016 Elsevier B.V. All rights reserved.