Cobalt-Phosphorus Decorated Graphene as Electrocatalyst for Oxygen Reduction Reactions: A Density Functional Theory Study

摘要

Proton exchange membrane fuel cells (PEMFCs) are extremely vital energy-conversion devices in the hydrogen economy. In the manuscript, the ORR electrocatalysis catalyzed by the Co/P doped graphene is investigated by the density functional theory calculations. The binding strength between Co and its coordination is -5.64 eV, being much stronger than the Co cohesive energy, which effectively guarantees the stability of Co atomic distribution. According to the adsorption affinity as well as the free energy, the P ligand is easily oxidized by the OH adsorption. Intriguingly, the presence of OH activator significantly boosts the ORR activity of Co/P doped graphene and the corresponding overpotential is reduced from 1.11 V to 0.73 V. Furthermore, the positive influence of P on the ORR activity is highlighted compared with CoC4 moiety possessed the overpotential of 0.92 V. This work provides the deep understanding of OH activation mechanism as well as the new strategy for the design of carbonbased materials as oxygen electrodes.