Chen Peng, Liu Ying, Xu Yarong, Guo Chenxi, Hu P
Key Laboratory for Advanced Materials, Centre for Computational Chemistry and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai200237, China.
Research Institute of Urumqi Petrochina Chemical Company, Urumqi83000, China.
JACS Au. 2022 Dec 19;3(1):165-175. doi: 10.1021/jacsau.2c00576. eCollection 2023 Jan 23.
The production of ethylene from ethane dehydrogenation (EDH) is of great importance in the chemical industry, where zeolites are reported to be promising catalysts and kinetic simulations using the energetics from quantum mechanical calculations might provide an effective approach to speed up the development. However, the kinetic simulations with rigorous considerations of the zeolite environment are not yet advanced. In this work, EDH over Fe/SAPO-34 is investigated using quantum mechanical calculations with kinetic simulations. We show that an excellent agreement between the reaction rates from the self-consistent kinetic simulations using the coverage-dependent kinetic model developed in this work and the experimental ones can be achieved. We demonstrate that the adsorbate-adsorbate interactions are of paramount importance to the accuracy of kinetic calculations for zeolite catalysts. Our self-consistent kinetic calculations illustrate that the CHCH• radical rather than CHCH* is a favored intermediate. Perhaps more importantly, we reveal that the traditional model to describe catalytic reactions in heterogeneous catalysis cannot be used for the kinetics of the system and it may not be appropriate for many real catalytic systems. This work not only builds a framework for accurate kinetic simulations in zeolites, but also emphasizes an important concept beyond the traditional model.
乙烷脱氢（EDH）制乙烯在化学工业中具有重要意义，据报道，沸石是很有前景的催化剂，利用量子力学计算得出的能量进行动力学模拟可能为加速该领域的发展提供有效途径。然而，对沸石环境进行严格考量的动力学模拟尚未取得进展。在这项工作中，我们使用量子力学计算和动力学模拟研究了Fe/SAPO - 34上的乙烷脱氢反应。我们发现，使用本工作中开发的基于覆盖度的动力学模型进行自洽动力学模拟得出的反应速率与实验反应速率之间能达成极佳的一致性。我们证明，吸附质 - 吸附质相互作用对沸石催化剂动力学计算的准确性至关重要。我们的自洽动力学计算表明，CHCH•自由基而非CHCH*是更受青睐的中间体。或许更重要的是，我们揭示了传统的描述多相催化中催化反应的模型不能用于该体系的动力学，并且可能不适用于许多实际的催化体系。这项工作不仅为沸石中的精确动力学模拟构建了框架，还强调了超越传统模型的一个重要概念。
