The methanol-to-hydrocarbons reaction refers collectively to a series of important industrial catalytic processes to produce either olefins or gasoline. Mechanistically, methanol conversion proceeds through a ‘pool’ of hydrocarbon species. For the methanol-to-olefins process, these species can be delineated broadly into ‘desired’ lighter olefins and ‘undesired’ heavier fractions that cause deactivation in a matter of hours. The crux in further catalyst optimization is the ability to follow the formation of carbonaceous species during operation. Here, we report the combined results of an operando Kerr-gated Raman spectroscopic study with state-of-the-art operando molecular simulations, which allowed us to follow the formation of hydrocarbon species at various stages of methanol conversion. Polyenes are identified as crucial intermediates towards formation of polycyclic aromatic hydrocarbons, with their fate determined largely by the zeolite topology. Notably, we provide the missing link between active and deactivating species, which allows us to propose potential design rules for future-generation catalysts.

甲醇制烃反应统指一系列重要的工业催化方法，用于生产烯烃或汽油。从机理上讲，甲醇转化是通过烃类的“库”进行的。对于甲醇制烯烃工艺，可以将这些物质大致划分为“所需的”较轻烯烃和“不需要的”较重馏分，这些馏分在数小时内引起失活。进一步优化催化剂的关键是在操作过程中跟踪碳质物质形成的能力。在这里，我们报告了操作性Kerr门控拉曼光谱研究与最先进的操作性分子模拟相结合的结果，这使我们能够追踪甲醇转化各个阶段中烃类的形成。多烯被认为是形成多环芳烃的关键中间体，其命运很大程度上取决于沸石的拓扑结构。值得注意的是，我们提供了活性和失活物质之间的缺失联系，这使我们能够为下一代催化剂提出潜在的设计规则。