Developing nonprecious group single-atom catalyst (SACs) based on alkaline earth metal has been rarely explored. Mg metal hampered the catalytic activity towards ORR due to the strong bonding of active centers with oxygenated group intermediate, whereas N-bonded Mg atoms have optimal bonding strength with intermediate oxygen species by adjusting the p-band center position. The co-ordination environment of Mg-Nx plays very crucial role in exhibiting the excellent catalytic activity towards ORR. We provide very simple MOF free methodology without any post acid treatment or any subsidiary sacrificial metal like Zn. The Mg-N-C catalyst exhibited a half-wave potential of 0.80 V versus the reversible hydrogen electrode, approaching the recently reported Fe-N-C catalyst. Electrochemical calculation further support the Mg-Nx sites as the origin of ORR via efficient 4-electron transfer pathway in basic medium. Importantly, current density is found to decrease less than 2% in diffusion limited current and loss of activity by only 13% at 0.9 V after 10,000 cycles in alkaline medium which far superior to the durability limit set by the US department of energy and overpasses the state-of-the-art Pt/C catalyst. The charge transfer resistance is the crucial parameter influencing on the ORR activity along with (pyridinic N+ pyrrolic N) content and degree of graphitization. This methodology can be applied to design a variety of other alkaline earth metal based M-N-C electrocatalysts and studied for various applications.

很少探索开发基于碱土金属的非贵族单原子催化剂（SAC）。镁金属由于活性中心与含氧基团中间基团之间的牢固键合而阻碍了对ORR的催化活性，而N键合的Mg原子通过调节p带中心位置具有与中间氧物种的最佳键合强度。Mg-Nx的配位环境在表现出优异的ORR催化活性方面起着至关重要的作用。我们提供非常简单的无MOF方法，无需任何后酸处理或任何辅助牺牲金属（如Zn）。与可逆氢电极相比，Mg-NC催化剂的半波电势为0.80 V，接近最近报道的Fe-NC催化剂。电化学计算进一步证实了Mg-Nx位点是通过碱性介质中有效的4电子转移途径作为ORR的起源。重要的是，发现在碱性介质中经过10,000次循环后，在扩散限制电流中电流密度在0.9 V时降低不到2％，而活性损失仅降低13％，远远超过了美国能源部设定的耐久性极限，并超过了最先进的Pt / C催化剂。电荷转移阻力是影响ORR活性以及（吡啶N +吡咯N）含量和石墨化程度的关键参数。该方法学可用于设计多种其他基于碱土金属的MNC电催化剂，并已针对各种应用进行了研究。发现在碱性介质中经过10,000次循环后，在扩散限制电流中电流密度降低不到2％，并且在0.9 V时活性降低仅13％，远远超过了美国能源部设定的耐久性极限，并超过了最先进的Pt / C催化剂。电荷转移阻力是影响ORR活性以及（吡啶N +吡咯N）含量和石墨化程度的关键参数。该方法学可用于设计多种其他基于碱土金属的MNC电催化剂，并已针对各种应用进行了研究。发现在碱性介质中经过10,000次循环后，在扩散限制电流中电流密度降低不到2％，并且在0.9 V时活性降低仅13％，远远超过了美国能源部设定的耐久性极限，并超过了最先进的Pt / C催化剂。电荷转移阻力是影响ORR活性以及（吡啶N +吡咯N）含量和石墨化程度的关键参数。该方法学可用于设计多种其他基于碱土金属的MNC电催化剂，并已针对各种应用进行了研究。电荷转移阻力是影响ORR活性以及（吡啶N +吡咯N）含量和石墨化程度的关键参数。该方法学可用于设计多种其他基于碱土金属的MNC电催化剂，并已针对各种应用进行了研究。电荷转移阻力是影响ORR活性以及（吡啶N +吡咯N）含量和石墨化程度的关键参数。该方法学可用于设计多种其他基于碱土金属的MNC电催化剂，并已针对各种应用进行了研究。