▎ 摘　　要

Essentially, the performance of single-atom catalysts (SACs) has been strongly affected by their supports. Herein, the structural, electronic, and catalytic properties of single-iron catalysts over defective graphene have been investigated under the scheme of density functional theory for the oxygen reduction reaction. Graphene with single and double vacancies offers the excellent capacity to anchor single iron, forming Fe-N-3 and Fe-N-4 bonding networks. Among these concept catalysts, Fe-N-4 located at double vacancies offers the highest catalytic activity with an overpotential of 0.81 V via the HOOH dissociation pathway, which allows Fe/DVG-N-4 to be regarded as available, low-cost, and high-efficiency catalyst.