Spatially Proximate Acid Sites in Zeolites Synergistically Boost Alkane Activation

Abstract

ABSTRACT The activation of light alkanes on zeolites has long been attributed to strong Brønsted acid sites (BAS), a focus that has constrained further catalyst development. Here, we report that in steamed ZSM‐5 zeolites, B 2 sites from partial hydrolysis of framework aluminum cooperate with neighboring classical BAS (B 1 ) to establish a proximate acid‐site microenvironment that substantially enhances both alkane adsorption and activation. Combining solid‐state NMR, in situ FTIR spectroscopy with two‐dimensional correlation analysis, and density functional theory calculations, we demonstrate that the neighboring B 1 /B 2 sites exhibit a stronger intrinsic affinity for propane than isolated B 1 sites, accelerating its accumulation within the pores, which is attributable to the locally optimized van der Waals interactions tuned by the Al─OH of B 2 . The resulting cooperative acid sites synergistically entrap alkane molecules and facilitate C─H bond activation, boosting propane conversion from 27.2% to 37.5%. Our findings reveal a mechanism for alkane activation that is driven by proximate acid‐site cooperativity rather than conventional acid strength of isolated BAS, opening an avenue for designing efficient zeolite catalysts via microenvironment engineering.