▎ 摘　　要

By density functional theory (DFT) calculations, it is found that the single-atom Fe anchored three Si modified defective graphene (3Si-graphene-Fe) exhibits the high stability, and this system is semiconducting property and has non-magnetic moment. Besides the most stable configurations, electronic structures and magnetic properties of adsorbed species (O-2, CO, 2CO and CO/O-2) on 3Si-graphene-Fe systems are comparably discussed. The adsorption of O-2 is more stable than that of CO molecule and the coadsorption of 2CO and CO/O-2 has the larger adsorption energy than that of the isolated one. The adsorbed O-2, CO and CO/O-2 can induce the change in magnetic properties of 3Si-graphene-Fe system, and the coadsorbed CO/O-2 on system exhibits the metallic property. Among the reaction mechanisms, the CO oxidation reactions through Eley-Rideal (ER) reactions have lower energy barriers (<0.5 eV) than those of the Langmuir-Hinshelwood (LH) and new termolecular Eley-Rideal (TER) mechanisms, indicating that the ER reaction as starting step is an energetically favourable process. These results provide an important guidance on validating the catalytic activity of single atom on graphene-based materials.