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 M₁M₂ DACs (referred to as M₁M₂N₆) and their complexes with ligand of *OH. According to the evaluation of catalytic activity and stability, NiNiN₆, NiCuN₆, CuCuN₆, and CoNiN₆(OH) were found to possess excellent ORR activity comparable to, even superior to Pt catalyst. Especially, NiNiN₆ 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 O₂ adsorption energy, the electronegativity of metal atoms, and the adsorption free energy of *OH (ΔG _*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 ΔG _*OH of 0.95 eV. This work provides a significant guidance for the discovery and design of highly active noble-metal-free ORR DACs.

中文翻译：

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通过第一性原理筛选探索用于氧还原反应的高效双金属位点电催化剂

作为氧还原电催化的新前沿，双原子催化剂（DAC）在燃料电池和金属空气电池的大规模商业化中展现出广阔的应用前景。在这里，我们提出了一种基于密度泛函理论的计算方案，以从一系列基于石墨烯的 N 配位 M ₁ M ₂ DAC（称为 M ₁ M ₂ N ₆ )及其与*OH配体的配合物。根据催化活性和稳定性评价，NiNiN ₆、NiCuN ₆、CuCuN ₆和CoNiN ₆(OH)被发现具有与 Pt 催化剂相当，甚至优于 Pt 催化剂的优异 ORR 活性。特别是，具有最低过电势 (0.35 V) 的 NiNiN ₆表现出最高的电化学活性，这应归因于 DAC 和 ORR 中间体之间适当的结合强度。此外，我们的结果表明，O ₂吸附能、金属原子的电负性和*OH的吸附自由能(ΔG _*OH ) 可用于定性预测 ORR 活性。从导出的经典火山图推断，对于 Δ，最佳过电势可以降低到 0.28 VG _{*0.95 eV 的 OH}。这项工作为发现和设计高活性无贵金属 ORR DAC 提供了重要指导。