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 carbon-based electrocatalysts.

Developing the optimized electrocatalysts with high Pt utilization as well as the outstanding performance for the oxygen reduction reaction (ORR) has raised great attention. Herein, the effects of the interlayer ZrC, HfC, or TiN and the multilayer Pt shell on the adsorption ability and the catalytic activity of the TiC@Pt core-shell structures are systemically investigated by density functional theory (DFT) calculations. For the sandwich structures, the presence of TiN significantly enhances the adsorption ability of the Pt shell, leading to the deterioration of the activity whilst the negligible influence of the ZrC and HfC insertion results the comparable performance with respect to TiC@Pt1ML. In addition, increasing the thickness of the Pt shell reduces the oxyphilic capacity and then mitigates the OH poisoning. From the free energy plots, the superior activity of TiC@Pt2ML is identified in comparison with 1ML and 3ML Pt shell. Herein, the improved activity with its high Pt atomic utilization makes the potential TiC@Pt2ML electrocatalyst for the future fuel cells.

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