Feeding Sequence Engineering of Beta Zeolite: Structure Tuning and Catalytic Performance in n -Butane Cracking

Precisely controlling the aluminum distribution and porosity in Beta zeolite is crucial for optimizing its catalytic performance. Herein, we report a facile but effective “bottom-up” method to achieve controllable regulation of the porosity and aluminum distribution of the final product by altering the feeding sequence of the silicon and aluminum sources. The aluminum-first route (Beta-Al) yielded ∼20 nm nanocrystals with an Al-rich surface and abundant intercrystalline mesopores, whereas the silicon-first route (Beta-Si) generated ∼400 nm large crystals with homogeneous Al distribution and intracrystalline mesopores. Mechanistic studies revealed that different feeding sequences led to distinct aluminosilicate precursors ([Si 8 Al] n vs [Si 4 Al] n ) and governed two crystallization pathways: solid–solid rearrangement for Beta-Al and dissolution–rearrangement for Beta-Si. When evaluated in n -butane catalytic cracking, Beta-Al exhibited higher activity and ethylene selectivity, while Beta-Si showed superior stability and propylene selectivity. This work demonstrates that feeding sequence engineering serves as a practical and industrially promising approach to tune Beta zeolite for targeted catalytic cracking applications. This strategy is simple, requires no post-treatment, and offers practical advantages for industrial catalyst manufacturing, where synthesis simplicity and low cost are highly valued.