▎ 摘　　要

Based on density functional theory, M-S-4 structure embedded graphene (MS4/C, where M = Fe, Co and Ni) as a novel catalyst for ORR has been studied. It is found that the ORR activity of MS4/C catalyst depends on the selection of central metal atom. The adsorption energies of ORR intermediates on CoS4/C are smaller than those on FeS4/C, but are larger than those on NiS4/C. Due to the optimal adsorption strength, the free energy change of the rate-determining step involved in ORR is more favorable for CoS4/C compared with FeS4/C and NiS4/C, suggesting that CoS4/C has a better catalytic activity. (C) 2015 Elsevier B.V. All rights reserved.