Theoretical inspection of TM-P4C single-atom electrocatalysts: High performance for oxygen reduction and evolution reactions

Developing the cost-effective or even bifunctional electrocatalysts for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) with industrially relevant activity is highly desired for metal-air batteries at the current stage. Herein, in this work, the catalytic performances of the single transition metal (TM) atom embeds graphene sheet with the tetra-coordinates Phosphorus (TMP4) for ORR and OER are investigated based on the density functional theory method. The results demonstrate that the most promising ORR and OER catalytic activity can be achieved on the CoP4 with the smallest potential gap Delta E and the lowest overpotential of 0.37 and 0.32 eV among all TMP4 systems, respectively, and the catalytic activity is even better than that of the traditional Pt and IrO2 catalysts. Furthermore, the AIMD and phonon dispersion calculations are conducted to confirm the thermodynamics and dynamics stability of CoP4. This work screens out promising candidates for novel graphenebased bifunctional ORR and OER catalysts and offers detailed microscopic insights into the mechanism of OER/ ORR, provides a theoretical guidance for the development of further single-atom catalysts.