Synthesis of single‐site catalysts whereby the local structure and the surrounding chemical environment are identical has been challenging particularly in heterogeneous catalysis as the support often presents spectrum of chemically distinct binding sites. Yet, the above criteria are crucial in attributing the apparent catalytic performance to the structural motif. The presented work augments on our previous work using monometallic molybdenum sulfide tethered within a zirconium‐based metal−organic framework (MOF), NU‐1000; the monometallic nature enables all presented sites to be catalytically addressable. As the molybdenum sulfide species resided within two distinct pores (micro‐ and mesopores) of the MOF support, we have imparted uniformity in the local chemical environment by reducing the pore heterogeneity down to a single mesopore. Single‐site and single‐atom nature of the candidate catalyst was established via X‐ray diffraction measurements. Redox mediators were implemented, which under a reductive potentials, provide reduced species; they can effectively deliver the necessary reducing equivalences to the catalytic units otherwise electrochemically unaddressable due to the low electron mobility within the framework. Our results indicate the micropore‐allocated molybdenum sulfide is ca. four times more active as to that in mesopores, while its catalytic mechanism is identical, underscoring the importance of controlling chemical environment beyond the active site.

中文翻译：

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单站点，单金属原子，多相电催化剂：金属有机骨架负载的硫化钼，用于氧化还原介体辅助的氢气释放反应

单一结构的催化剂的合成，其局部结构和周围的化学环境是相同的，在多相催化中尤其具有挑战性，因为载体通常会呈现出化学上不同的结合位点。然而，上述标准对于将表观催化性能归因于结构基元是至关重要的。提出的工作扩大了我们以前在基于锆的金属有机框架（MOF）NU-1000中使用单金属硫化钼进行束缚的工作；单金属性质使得所有存在的位点都可以被催化寻址。由于硫化钼物质位于MOF载体的两个不同的孔（微孔和中孔）中，我们通过将孔的异质性降低到单个中孔来赋予了局部化学环境均匀性。候选催化剂的单位和单原子性质是通过X射线衍射测量确定的。实施了氧化还原介体，其在还原电位下提供了减少的物种；它们可以有效地将必要的还原当量传递给催化单元，否则由于骨架内的低电子迁移率，电化学上无法解决这些催化单元。我们的结果表明，微孔分配的硫化钼约为。其活性是中孔活性的四倍，而其催化机理是相同的，从而强调了在活性位点以外控制化学环境的重要性。它们可以有效地将必要的还原当量传递给催化单元，否则由于骨架内的低电子迁移率，电化学上无法解决这些催化单元。我们的结果表明，微孔分配的硫化钼约为。其活性是中孔活性的四倍，而其催化机理是相同的，从而强调了在活性位点以外控制化学环境的重要性。它们可以有效地将必要的还原当量传递给催化单元，否则由于骨架内的低电子迁移率，电化学上无法解决这些催化单元。我们的结果表明，微孔分配的硫化钼约为。其活性是中孔活性的四倍，而其催化机理是相同的，从而强调了在活性位点以外控制化学环境的重要性。