▎ 摘　　要

Development of effective bifunctional electrocatalysts for the oxygen electrode reaction is desirable. In this work, the electrocatalytic performance of transition metals and oxygen (TM/O) codecorated graphene is evaluated by density functional theory calculations. The outstanding NiO2-pen moiety (a NiO2C2 structure with O atoms in the pentatomic ring) is screened out due to its low overpotential and good stability. Furthermore, the results indicate that the catalytic activity of TM/O sites is inversely correlated with the binding energy E-b. The enhanced E-b weakens the adsorption ability and decreases the corresponding overpotentials. Our finding provides a rational strategy to design functional carbonbased electrocatalysts.