Resolving the deactivation mechanism of zeolite in methanol to olefins (MTO) and clarifying the formation and evolution of coke precursors (e.g., polycyclic aromatic hydrocarbons [PAHs]) are crucial to understanding the whole MTO process; however, they are challenging due to the extraordinarily complex reaction network. Herein, the deactivation behavior of typical zeolite catalysts (viz., H-SSZ-13, H-beta, and H-ZSM-5) in MTO was investigated. The results indicate that the alkylation of cyclic intermediates (e.g., methylbenzene and cyclohexene) with cyclic carbocations (e.g., cyclopentadienyl and cyclohexadienyl cations) is a main manner to form PAHs and that the cross-linked PAHs act as the primary coke precursors. In addition, the formation of coke precursors is related to zeolite pore structure. The large intra-crystalline space of H-SSZ-13 and H-Beta provides enough reaction space for the alkylation and cross-linking of cyclic intermediates, whereas for H-ZSM-5, with smaller intra-crystalline space, the alkylation and cross-linking of cyclic intermediates are more energy demanding.

解决甲醇制烯烃（MTO）中沸石的失活机理并阐明焦炭前体（例如多环芳烃[PAHs]）的形成和演化对于理解整个MTO过程至关重要；然而，由于反应网络极其复杂，它们具有挑战性。在此，研究了典型沸石催化剂（即 H-SSZ-13、H-beta 和 H-ZSM-5）在 MTO 中的失活行为。结果表明，环状中间体（如甲苯和环己烯）与环状碳阳离子（如环戊二烯基和环己二烯基阳离子）的烷基化是形成PAHs的主要方式，并且交联的PAHs充当初级焦炭前体。此外，焦炭前驱体的形成与沸石的孔结构有关。 H-SSZ-13和H-Beta较大的晶内空间为环状中间体的烷基化和交联提供了足够的反应空间，而H-ZSM-5的晶内空间较小，为烷基化和交联提供了足够的反应空间。环状中间体的连接需要更多的能量。