Dihydrogen complexes, which retain the H–H bond, have been extensively studied in molecular science and found to be prevalent in homogeneous and enzymatic catalysis. However, their counterparts in heterogeneous catalysis, specifically nondissociative chemisorbed dihydrogen binding on the catalyst surface, are rarely reported experimentally. This scarcity is due to the complexity of typical material surfaces and the lack of effective characterization techniques to prove and distinguish various dihydrogen binding modes. Herein, using high-pressure operando solid-state NMR technology, we report the first unambiguous experimental observation of activated dihydrogen binding on a reduced ceria catalyst through interactions with surface oxygen vacancies. By employing versatile NMR structural and dynamical analysis methods, we establish a proportional relationship between the degree of ceria surface reduction and dihydrogen binding, as evidenced by NMR observations of H-D through-bond coupling (J_HD), T₁ relaxation, and proton isotropic chemical shifts. In situ NMR analysis further reveals the participation of bound dihydrogen species in a room-temperature ethylene hydrogenation reaction. The remarkable similarities between surface-activated dihydrogen in heterogeneous catalysis and dihydrogen model molecular complexes can provide valuable insights into the hydrogenation mechanism for many other solid catalysts, potentially enhancing hydrogen utilization.

中文翻译：

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高压操作固态核磁共振波谱揭示了 CeO2 上的非解离活化二氢键


保留 H-H 键的二氢配合物已在分子科学中得到广泛研究，并发现在均相催化和酶催化中普遍存在。然而，它们在多相催化中的对应物，特别是催化剂表面上的非解离化学吸附氢气的结合，很少有实验报道。这种稀缺性是由于典型材料表面的复杂性以及缺乏有效的表征技术来证明和区分各种二氢结合模式。在此，我们利用高压原位固态核磁共振技术，首次明确地观察到活化的氢气通过与表面氧空位的相互作用而结合在还原的二氧化铈催化剂上。通过采用通用的 NMR 结构和动力学分析方法，我们建立了二氧化铈表面还原程度和二氢结合之间的比例关系，这一点通过 HD 通过键耦合 ( J _HD )、 T ₁弛豫和质子各向同性化学的 NMR 观察得到证明轮班。原位核磁共振分析进一步揭示了结合二氢物种在室温乙烯氢化反应中的参与。多相催化中表面活化的氢气与氢气模型分子复合物之间的显着相似性可以为许多其他固体催化剂的加氢机理提供有价值的见解，从而有可能提高氢气的利用率。