This computational study explores the structural stability and catalytic performance of FeMn-based dual-atom catalysts (DACs) embedded in graphitic materials, focusing on active sites located at graphene edges. Using density functional theory (DFT) calculations and microkinetic simulations, we show that graphitic edges, particularly armchair edges, effectively stabilize the ortho-configured FeMnN₆ active site. This configuration demonstrates enhanced catalytic performance for the oxygen reduction reaction (ORR) compared to FeMnN₆ sites at zigzag edges or on basal graphene. In contrast, initial para-configured FeMnN₆ and MnFeN₆ active sites exhibit limited ORR activity due to OH- or O-poisoning. Interestingly, the presence of adsorbed *OH and *O intermediates not only stabilizes the system but also improves catalytic efficiency, enabling effective ORR activation. Acid stability calculations further reveal that while the ortho configuration performs well in high-pH environments, the poisoned para configuration offers broader pH tolerance, indicating complementary strengths. Overall, the findings highlight the critical role of edge effects in shaping the stability and functionality of FeMnN₆ and MnFeN₆ active sites, offering valuable insights for the development of efficient nonprecious metal catalysts for ORR applications.

中文翻译：

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增强石墨烯边缘负载的铁-锰双原子的稳定性和催化性能，用于氧还原反应

这项计算研究探讨了嵌入石墨材料中的 FeMn 基双原子催化剂 （DAC） 的结构稳定性和催化性能，重点关注位于石墨烯边缘的活性位点。使用密度泛函理论 （DFT） 计算和微动力学模拟，我们表明石墨边缘，尤其是扶手椅边缘，有效地稳定了邻位配置的 FeMnN ₆ 活性位点。与锯齿形边缘或基底石墨烯上的 FeMnN ₆ 位点相比，这种配置显示出增强的氧还原反应 （ORR） 催化性能。相比之下，由于 OH 或 O 中毒，初始对位配置的 FeMnN ₆ 和 MnFeN ₆ 活性位点表现出有限的 ORR 活性。有趣的是，吸附的 *OH 和 *O 中间体的存在不仅可以稳定系统，还可以提高催化效率，从而实现有效的 ORR 活化。酸稳定性计算进一步表明，虽然邻位构型在高 pH 值环境中表现良好，但中毒对位构型提供了更广泛的 pH 耐受性，表明互补优势。总体而言，研究结果强调了边缘效应在塑造 FeMnN ₆ 和 MnFeN ₆ 活性位点的稳定性和功能方面的关键作用，为开发用于 ORR 应用的高效非贵金属催化剂提供了有价值的见解。