The character of coke is typically regarded as a “deactivator” in zeolite catalysis. We report the interdependence of coke nature and location with its true character in the mechanisms of ethylene oligomerization: a model zeolite catalyzed transformation involved in many sustainable processes. We prepared, characterized, and tested ZSM-5 zeolites of different diffusion paths and acidities, using polymeric-, organic-template, or template-free strategies and various Si/Al ratios. The results indicate that coke can improve the selectivity/yield of higher olefins and jet-fuel aliphatics, and this positive effect is better than modifying the number of acid sites. The molecular-level nature of these coke species is elucidated using high-resolution mass spectrometry. The “enhancer” character of the coke can be better exploited in polymeric templated (hierarchical) ZSM-5 zeolite because mesopores retain coke without critically affecting accessibility or causing deactivation. Furthermore, this catalyst is stable for at least 74 h on stream and in multiple reaction-regeneration cycles.

焦炭的特性通常被认为是沸石催化中的“钝化剂”。我们报告了焦炭性质和位置的相互依赖性及其在乙烯低聚机制中的真实特征：参与许多可持续过程的模型沸石催化转化。我们使用聚合物模板、有机模板或无模板策略和各种 Si/Al 比制备、表征和测试了不同扩散路径和酸度的 ZSM-5 沸石。结果表明，焦炭可以提高高级烯烃和喷气燃料脂肪族化合物的选择性/收率，这种积极作用优于改变酸位点的数量。使用高分辨率质谱法阐明了这些焦炭种类的分子水平性质。焦炭的“增强剂”特性可以在聚合模板化（分层）ZSM-5 沸石中得到更好的利用，因为中孔保留焦炭而不会严重影响可及性或导致失活。此外，该催化剂在运行和多个反应再生循环中至少稳定 74 小时。