Exploring Highly Efficient Dual-Metal-Site Electrocatalysts for Oxygen Reduction Reaction by First Principles Screening

Emerging as a new frontier in oxygen reduction electrocatalysis, dual-atom catalysts (DACs) exhibit a promising application prospect in the large-scale commercialization of fuel cells and metal–air batteries. Here, we present a density-functional theory-based computational scheme to identify highly active noble-metal-free DACs for oxygen reduction reaction (ORR) from a series of graphene-based N-coordinated M 1 M 2 DACs (referred to as M 1 M 2 N 6 ) and their complexes with ligand of *OH. According to the evaluation of catalytic activity and stability, NiNiN 6 , NiCuN 6 , CuCuN 6 , and CoNiN 6 (OH) were found to possess excellent ORR activity comparable to, even superior to Pt catalyst. Especially, NiNiN 6 with the lowest overpotential (0.35 V) exhibited the highest electrochemical activity, which should be attributed to the appropriate binding strength between DAC and ORR intermediates. Furthermore, our results demonstrated that the O 2 adsorption energy, the electronegativity of metal atoms, and the adsorption free energy of *OH (Δ G *OH ) can be used to qualitatively predict the ORR activity. It was inferred from the derived classic volcano plot that the optimal overpotential could be lowered to 0.28 V for Δ G *OH of 0.95 eV. This work provides a significant guidance for the discovery and design of highly active noble-metal-free ORR DACs.