Unraveling the Nature of Extraframework Catalytic Ensembles in Zeolites: Flexibility and Dynamics of the Copper-Oxo Trimers in Mordenite,The Journal of Physical Chemistry Letters

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Unraveling the Nature of Extraframework Catalytic Ensembles in Zeolites: Flexibility and Dynamics of the Copper-Oxo Trimers in Mordenite
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2021-11-03 , DOI: 10.1021/acs.jpclett.1c03288
Elena V Khramenkova ₁ , Michael G Medvedev ₂ , Guanna Li _{3,

4} , Evgeny A Pidko ₁

Affiliation

Extraframework cations define the chemical versatility of zeolite catalysts. Addressing their structural complexity and dynamic behavior represents one of the main fundamental challenges in the field. Herein, we present a computational approach for the identification and analysis of the accessible pool of intrazeolite extraframework complexes with a Cu/MOR catalyst as an industrially important model system. We employ ab initio molecular dynamics for capturing the ensemble of reactive isomers with the [Cu₃O₃]²⁺ stoichiometry confined in the mordenite channels. The high structural diversity of the generated isomers was ensured by concentrating the kinetic energy along the low-curvature directions of the potential energy surface (PES). Geometrically distinct [Cu₃O₃]²⁺ complexes were identified via a series of clustering procedures ensuring that one structure of each local minima is retained. The proposed procedure has resulted in a set of previously unknown peroxo-complexes, which are >50 kJ/mol more stable than the recently hypothesized chair-shaped structure. Our analysis demonstrates that the most stable peroxo-containing clusters can be formed under operando conditions from molecular oxygen and the Cu₃O unit, similar to that in methane monooxygenase (MMO) enzymes.

中文翻译：

揭示沸石中超框架催化集合的性质：丝光沸石中铜-氧代三聚体的灵活性和动力学

超骨架阳离子定义了沸石催化剂的化学多功能性。解决它们的结构复杂性和动态行为是该领域的主要基本挑战之一。在此，我们提出了一种计算方法，用于识别和分析具有 Cu/MOR 催化剂的沸石内框架外配合物的可访问池，作为工业上重要的模型系统。我们采用从头分子动力学来捕获具有 [Cu ₃ O ₃ ] ²⁺的反应异构体的集合化学计量限制在丝光沸石通道中。通过沿势能面 (PES) 的低曲率方向集中动能，确保了生成的异构体的高度结构多样性。通过一系列聚类程序确定了几何上不同的 [Cu ₃ O ₃ ] ²⁺配合物，以确保保留每个局部最小值的一个结构。所提出的程序产生了一组以前未知的过氧复合物，它们比最近假设的椅子形结构更稳定 > 50 kJ/mol。我们的分析表明，最稳定的含过氧簇可以在操作条件下由分子氧和 Cu ₃O 单位，类似于甲烷单加氧酶 (MMO) 中的单位。

更新日期：2021-11-11

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