To attain a circular carbon economy and resolve CO₂ electroreduction technology obstacles, single-atom catalysts (SACs) have emerged as a logical option for electrocatalysis because of their extraordinary catalytic activity. Among SACs, metal–organic frameworks (MOFs) have been recognized as promising support materials because of their exceptional ability to prevent metal aggregation. This study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100% for CO formation in H-cell and three-compartment microfluidic flow-cell reactors and an excellent turnover frequency of 23,699 h⁻¹, validating their intrinsic catalytic potential. These results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets, which are linked to the evaporation of Zn-containing organic linkers during pyrolysis. Furthermore, using X-ray absorption spectroscopy and density functional theory calculations, a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO* preadsorbed sites as initial states was possible and provided valuable insights.

中文翻译：

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晶体空位诱导的 MOF 纳米片作为合理的单原子支撑加速 CO2 电还原为 CO

为了实现循环碳经济并解决CO ₂电还原技术障碍，单原子催化剂（SAC）因其非凡的催化活性而成为电催化的合理选择。在SAC中，金属有机框架（MOF）因其具有防止金属聚集的特殊能力而被认为是有前途的支撑材料。这项研究表明，精确设计的 MOF 纳米片上原子分散的 Ni 单原子在 H 电池和三室微流控流通池反应器中形成 CO 时表现出约 100% 的高法拉第效率，并且具有 23,699 h -1 的优异周转^频率，验证其内在催化潜力。这些结果表明，晶体学变化影响 MOF 纳米片上丰富的空位位点，这与热解过程中含锌有机连接体的蒸发有关。此外，利用X射线吸收光谱和密度泛函理论计算，可以对不饱和原子配位环境和涉及CO*预吸附位点作为初始状态的潜在机制进行全面研究，并提供了有价值的见解。