Metal–organic framework (MOF)‐derived materials have attracted increasing interest and show promising catalytic performances in many fields. Intensive efforts have been focused on the structure design and metal‐site integration in MOF‐derived catalysts. However, the key catalytic processes related with the metal sites in MOF‐derived catalysts that dominate the electrocatalytic performance still remain obscure. Herein, we show a neglected but critical issue in the pyrolytic synthesis of MOF‐derived catalysts: the coupled evolution of dual sites, that is, metallic sites and single‐atom metal sites. The identification of active sites of single‐atom sites from the visible particles has been elucidated through the combined X‐ray spectroscopic, electron microscopic, and electrochemical studies. Interestingly, after a total removal of metallic cobalt sites, catalysts with purified single‐atom metal sites show no faltering activity for either the oxygen reduction reaction (ORR) or hydrogen evolution reaction (HER), while significantly enhanced ORR selectivity is achieved; this reveals the dominant activity and selectivity contribution from single‐atom electrocatalysis. The insight of the coupled evolution of dual sites and the as‐demonstrated dual‐site decoupling strategies open up a new routine for the design and synthesis of MOF‐derived catalysts with the optimized single‐atom electrocatalysis towards various electrochemical reactions.

中文翻译：

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金属-有机框架（MOF）衍生的双功能催化剂中的关键单原子电催化

金属有机框架（MOF）衍生的材料引起了越来越多的兴趣，并在许多领域显示出令人鼓舞的催化性能。MOF衍生的催化剂一直致力于结构设计和金属-位点集成。但是，与MOF衍生的催化剂中的金属位点有关的，主导电催化性能的关键催化过程仍然不清楚。本文中，我们在MOF衍生的催化剂的热解合成中显示了一个被忽略但至关重要的问题：双位点（即金属位点和单原子金属位点）的耦合演化。通过结合X射线光谱，电子显微镜和电化学研究，已经阐明了从可见粒子中识别单原子位点的活性位点。有趣的是，在完全除去金属钴位点之后，具有纯化的单原子金属位点的催化剂对氧还原反应（ORR）或氢释放反应（HER）均没有显示减弱的活性，而ORR选择性则显着提高。这揭示了单原子电催化的主要活性和选择性贡献。对双位点耦合演化和所示的双位点去偶联策略的深刻见识为MOF衍生的催化剂的设计和合成开辟了新的程序，并针对各种电化学反应优化了单原子电催化。这揭示了单原子电催化的主要活性和选择性贡献。对双位点耦合演化和所示的双位点去偶联策略的深刻见识为MOF衍生的催化剂的设计和合成开辟了新的程序，并针对各种电化学反应优化了单原子电催化。这揭示了单原子电催化的主要活性和选择性贡献。对双位点耦合演化和所示的双位点去偶联策略的深刻见识为MOF衍生的催化剂的设计和合成开辟了新的程序，并针对各种电化学反应优化了单原子电催化。