Post‐Shaping Over‐Impregnation: A Facile Strategy for Pt‐KL Catalysts With Ultrahigh Metal Dispersion and Enhanced Aromatization Performance

ABSTRACT The precise localization of metal clusters within zeolite frameworks is critical for the aromatization catalysis. In this study, a simple post‐shaping over‐impregnation (PSOI) method was developed for the industrial‐scale fabrication of Pt/KL catalysts with controlled platinum distributions, which was applied after the zeolite shaping process. Even with this simple method, we discovered that merely adjusting the metal loading provides a controllable means to position Pt clusters either near the pore entrances or deep within the channels‐a strategy vividly exemplified by the enhanced aromatization performance achieved when Pt clusters are confined within the linear channels of the KL zeolite. The location of Pt clusters was determined by HAADF‐STEM, ZLC, CO‐DRIFTS, XPS, and H 2 pulse chemisorption measurements. Molecular diffusion studies based on the Zero Length Column ( ZLC ) method revealed that the optimized intra‐channel Pt distribution at 0.37 wt% loading yielded a maximal diffusion time constant ( D/R 2 ) and moderate activation energy for n‐hexane transport, facilitating efficient reactant and product diffusion. At a loading of 0.37 wt%, Pt preferentially occupies internal channel sites, resulting in 82.4% aromatic selectivity during n‐hexane aromatization at 440°C. In situ DRIFTS spectroscopy further reveals the formation and evolution of olefinic, cyclic, and aromatic species associated with channel‐confined Pt clusters. Deviation from the optimal Pt loading leads to superficial Pt deposition and pore crowding, resulting in diffusion limitations and a pronounced decline in aromatization performance. These results demonstrate that post‐shaping spatial control of Pt clusters establishes a direct relationship between structure, diffusion, and reactivity and provides a practical industrially viable strategy for optimizing zeolite‐based aromatization catalysts.