Molecular Routes of Dynamic Autocatalysis for Methanol-to-Hydrocarbons Reaction

作者：Shanfan Lin, Yuchun Zhi, Wei Chen, Huan Li, Wenna Zhang, Caiyi Lou, Xinqiang Wu, Shu Zeng, Shutao Xu, Jianping Xiao, Anmin Zheng, Yingxu Wei, Zhongmin Liu · 发表于：Journal of the American Chemical Society · 年份：2021 · DOI：10.1021/jacs.1c03475 · 被引用次数：115 · 研究领域：Zeolite Catalysis and Synthesis、Catalysis and Oxidation Reactions、Advanced NMR Techniques and Applications

The industrially important methanol-to-hydrocarbons (MTH) reaction is driven and sustained by autocatalysis in a dynamic and complex manner. Hitherto, the entire molecular routes and chemical nature of the autocatalytic network have not been well understood. Herein, with a multitechnique approach and multiscale analysis, we have obtained a full theoretical picture of the domino cascade of autocatalytic reaction network taking place on HZSM-5 zeolite. The autocatalytic reaction is demonstrated to be plausibly initiated by reacting dimethyl ether (DME) with the surface methoxy species (SMS) to generate the initial olefins, as evidenced by combining the kinetic analysis, in situ DRIFT spectroscopy, 2D 13 C– 13 C MAS NMR, electronic states, and projected density of state (PDOS) analysis. This process is operando tracked and visualized at the picosecond time scale by advanced ab initio molecular dynamics (AIMD) simulations. The initial olefins ignite autocatalysis by building the first autocatalytic cycle—olefins-based cycle—followed by the speciation of methylcyclopentenyl (MCP) and aromatic cyclic active species. In doing so, the active sites accomplish the dynamic evolution from proton acid sites to supramolecular active centers that are experimentally identified with an ever-evolving and fluid feature. The olefins-guided and cyclic-species-guided catalytic cycles are interdependently linked to forge a previously unidentified hypercycle, being composed of one “selfish” autocata...