▎ 摘　　要

First-principles electronic structure calculations based on spin-polarized density functional theory were carried out to study the adsorption of oxygen-containing functional groups -OH, -CHO, and -COOHon a two-dimensional (2D) infinite graphene sheet without edge states and defects. We find that the energy gain of adsorption can be significantly improved when the graphene sheet is supported via a point contact, a prototype for graphene sheet supported by catalysts, nanoparticles or nanopillars, or a surface with steps, edges, adatoms, or defects. This was modeled by placing a single atom of Fe, Co, and Ni under the graphene surface. Thus supported graphene not only becomes magnetic, but the carbon atoms in contact with the metal atoms become chemically more active as well. The use of point contact support to improve adsorption has advantages over that of introducing defects: (1) It does not destroy the intrinsic 2D geometry of the graphene sheet. (2) Patterned structures can be created by tailoring the position of the metal atoms supporting the graphene sheet. (3) The geometry distortion created by point contact can be made more uniform and lead to better adsorption energies. (4) Reduction of the work function of supported graphene makes the manipulation of electrons more flexible and controllable in tuning their electronic structure and magnetic properties.