Staged Synergy of Spatially Coupled Brønsted and Ga Lewis Acid Sites on Ga-doped HY Zeolite for Cascade Conversion of Dimethylfuran to para -Xylene

Abstract Catalytic valorization of biomass-derived 2,5-dimethylfuran into para-xylene (p-X) is frequently bottlenecked by the stochastic distribution of multiple acid sites in conventional metal-doped zeolites, which obscures the nature of acid-site cooperativity. To address this heterogeneity, we present a template-free in situ crystallization protocol that embeds gallium into the FAU architecture, enabling controlled modulation of the speciation and spatial proximity of different acid sites via the initial gel composition. The optimized construct, with 3.58 wt % Ga and 9.94 wt % Al, delivers a p-X productivity of 58.9 mmolp-X·gcat.–1·h–1 under mild reaction conditions. By integrating multi-scale characterizations and kinetic analysis, we identify a catalytically relevant ensemble specifically as tetrahedral extra-framework Ga Lewis sites (Ga-L) residing in close spatial proximity to framework Al Brønsted acid sites (Al-B). Interpretable symbolic regression elucidates a distinct “relay-type” synergy: the proximal Ga-L and Al-B effectively promote the initial Diels–Alder cycloaddition, whereas the subsequent dehydration step is governed primarily by Brønsted acidity. DFT calculations validate this spatially coupled synergy, which directs electron transfer in DMF and stabilizes a metastable intermediate, thereby lowering the activation barrier of the rate-determining cycloaddition step.