The design of diatomic catalysts with uniformly dispersed metal atoms is expected to improve catalytic performance, which is conducive to the intensive comprehending of the synergistic mechanism between dual-metal sites for the oxygen evolution reaction (OER) at the atomic level. Herein, we design a strategy to immobilize bimetallic Fe-Co atoms onto nitrogen-doped graphene to obtain a diatomic catalyst (DA-FC-NG) with FeN₃-CoN₃ configuration. The DA-FC-NG shows excellent OER activity with a low overpotential (η₁₀ = 268 mV), which is superior to commercial iridium dioxide catalysts. Theoretical calculations uncover that the excellent activity of DA-FC-NG is due to the interaction between Fe and Co diatoms, which causes charge rearrangement and induces the adsorption of intermediates on the Fe–O–Co bridge structure, thus improving the catalytic OER performance. This work is of great significance for the design of highly active diatomic catalysts to replace noble metal catalysts for energy-related applications.

Developing transition metal-nitrogen-carbon materials (M-N-C) as electrocatalysts for the oxygen evolution reaction (OER) is significant for low-cost energy conversion systems. Further d-orbital adjustment of M center in M-N-C is beneficial to the improvement of OER performance. Herein, we synthesize a single-Mn-atom catalyst based on carbon skeleton (Mn₁-N₂S₂C_x) with isolated Mn-N₂S₂ sites, which exhibits high alkaline OER activity (η₁₀ = 280 mV), low Tafel slope (44 mV·dec⁻¹), and excellent stability. Theoretical calculations reveal the pivotal function of isolated Mn-N₂S₂ sites in promoting OER, including the adsorption kinetics of intermediates and activation mechanism of active sites. The doping of S causes the increase in both charge density and work function of active Mn center, and ortho-Mn₁-N₂S₂C_x expresses the fastest OER kinetics due to the asymmetric plane.

Lack of high-efficiency, cost-efficient, and well-stocked oxygen evolution reaction (OER) electrocatalysts is a main challenge in large-scale implementation of electrolytic water. By regulating the electronic structure of isolated single-atom metal sites, high-performance transition-metal-based catalysts can be fabricated to greatly improve the OER performance. Herein, we demonstrate single-atom manganese coordinated to nitrogen and sulfur species in two-dimensional graphene nanosheets Mn-NSG (NSG means N- and S- codoped graphene) as an active and durable OER catalyst with a low overpotential of 296 mV in alkaline media, compared to that of the benchmark IrO₂ catalyst. Theoretical calculations and experimental measurements reveal that the Mn-N₃S sites in the graphene matrix are the most active sites for the OER due to modified electronic structure of the Mn site by three nitrogen and one sulfur atoms coordination, which show lower theoretical overpotential than the Mn-N₄ sites and over which the O–O formation step is the rate-determining step.