Extension and clustering of polycyclic aromatic hydrocarbons (PAHs) are key mechanistic steps for coking and deactivation in catalysis reactions. This paper reports a strategy integrating high-resolution MALDI FT-ICR mass spectrometry with isotope labeling to unveil a complete route for aromatic hydrocarbon evolution in SAPO-34-catalyzed methanol-to-olefins (MTO). A previously unrecognized mechanism, cage-passing growth forming cross-linked multi-core PAHs with a graphene-like structure, is elucidated. This mechanism is shown to be general for other cage-based molecular sieves, providing a versatile means to decipher PAH growth in catalysis and combustion.
