Interplay of Electronic and Steric Effects to Yield Low‐Temperature CO Oxidation at Metal Single Sites in Defect‐Engineered HKUST‐1
Interplay of Electronic and Steric Effects to Yield Low‐Temperature CO Oxidation at Metal Single Sites in Defect‐Engineered HKUST‐1
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DOI：
10.1002/anie.202000385
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发表时间：
2020-03
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通讯作者：
Weijia Wang;Dmitry I. Sharapa;A. Chandresh;A. Nefedov;S. Heissler;L. Heinke;F. Studt;Yuemin Wang;C. Wöll
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文献类型：
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作者：
Weijia Wang;Dmitry I. Sharapa;A. Chandresh;A. Nefedov;S. Heissler;L. Heinke;F. Studt;Yuemin Wang;C. Wöll
与沉积在氧化物纳米颗粒上的催化活性金属单原子相反，金属有机框架（MOF）的结晶性质允许对反应机制进行彻底表征。使用无缺陷的HKUST-1 MOF薄膜，我们证明了通过减少完整框架的原始Cu 2 +/Cu 2+对以受控方式产生的Cu+/Cu 2+二聚体缺陷，在低温CO氧化中具有高催化活性。结合先进的红外光谱和密度泛函理论，我们提出了一个新的反应机制，其中的关键中间体是不带电的O2物种，弱结合到Cu+/Cu 2+。我们的研究结果揭示了一个复杂的电子和空间效应之间的相互作用在缺陷位点的MOFs和提供重要的指导方针，定制和利用单金属原子位点的催化活性。
Abstract In contrast to catalytically active metal single atoms deposited on oxide nanoparticles, the crystalline nature of metal‐organic frameworks (MOFs) allows for a thorough characterization of reaction mechanisms. Using defect‐free HKUST‐1 MOF thin films, we demonstrate that Cu+/Cu2+ dimer defects, created in a controlled fashion by reducing the pristine Cu2+/Cu2+ pairs of the intact framework, account for the high catalytic activity in low‐temperature CO oxidation. Combining advanced IR spectroscopy and density functional theory we propose a new reaction mechanism where the key intermediate is an uncharged O2 species, weakly bound to Cu+/Cu2+. Our results reveal a complex interplay between electronic and steric effects at defect sites in MOFs and provide important guidelines for tailoring and exploiting the catalytic activity of single metal atom sites.