Spatial Engineering of Acidity in Hierarchical Zeolites for Enhanced Methanol‐to‐Olefins Catalysis

ABSTRACT The spatial distribution and accessibility of acidic sites are critical for optimizing zeolite catalytic performance. Hierarchical zeolites with efficient diffusion pathways enhance acid‐site accessibility, yet spatially resolving these accessible sites remains challenging. Here, we present a versatile and controllable strategy for synthesizing hierarchical ZSM‐5 zeolites with spatially tunable, highly accessible acid sites. Uniformly distributed (OMMS‐ZSM‐5(H)) and shell‐enriched (OMMS‐ZSM‐5(A)) acid domains were selectively fabricated by modulating precursor composition and water content. Confocal laser scanning microscopy (CLSM) with fluorescent probes directly visualizes acid site distribution and intracrystalline diffusion, revealing significantly enhanced accessibility. OMMS‐ZSM‐5(H) demonstrates superior MTO performance, with an ultralow deactivation rate of 9.9 × 10 −3 h −1 and a 33 h lifetime, 16 times longer than conventional ZSM‐5. This improved stability is attributed to the hierarchical acid sites, which increase molecular diffusion to ∼10 −15 m 2 s −1 , two orders of magnitude greater than conventional ZSM‐5, and outperform shell‐enriched analogues. This work establishes a strategy for designing high‐performance zeolite catalysts through spatial control engineering of accessible acidic sites.