Simultaneous Modulation of Mesoporosity and Al Siting for Superior Performance Zeolite Catalyst in Ethylene...

Porosity and Al siting are key levers for optimizing zeolite catalysts, yet they are often addressed independently due to the lack of effective integrated tuning strategies. Herein, we report an integrative methodology for preparing hierarchical zeolite (Z_F) with interconnected mesostructures and tunable Al siting, achieved via regioselective dissolution of Al-rich domains by presetting accessible and inaccessible zones within parent zeolite (Z_P). Remarkably, ∼60% of the framework channels' Al atoms were selectively removed without impairing the channel intersections' Al atoms. Despite a 39% reduction in Brønsted acid sites (BAS), Z_F exhibits a 1.8-fold higher turnover frequency (TOF) than Z_P during ethylene transformation at 973K, attributable to the introduction of mesoporosity. Notably, site-specific ³¹P NMR analysis reveals that BAS located at channel intersections exhibits a TOF of 516 h^-1, which is 13 times higher than that of sites within the channels (40 h^-1). The hierarchical zeolite also demonstrates superior durability and enhanced aromatic selectivity compared to Z_P. These results highlight the synergistic benefits of simultaneously tuning porosity and Al siting, offering a new paradigm for the rational design of high-performance zeolite catalysts and providing deeper insights into the interplay between structure and function in zeolite-based catalysis.