To overcome diffusional limitations associated with the catalytic cracking of large hydrocarbons, a novel core-shell hierarchical zeolite has been developed and evaluated. Large, branched hydrocarbons encounter diffusional limitations in micropores of zeolites for cracking reactions, a limitation overcome by improved textural properties of hierarchical zeolites, leading to enhanced cracking activity. This will result in an improvement in deactivation rate, cracking activity, and enhanced product selectivity towards light hydrocarbon products. The impact of chain length involving a long chain paraffin (hexadecane) and a highly branched aromatic (1,3,5-TIPB) was also investigated to study the influence of the presence of the micro-mesopore network in overcoming diffusion limitations.

This paper investigates the use of hierarchical core-shell BEA@NanoZSM-5 in the catalytic cracking of 1,3,5 triisopropylbenzene (1,3,5-TIPB), and n-hexadecane (C₁₆). The novel hierarchical composite was synthesized by preliminary seeding of the core BEA crystals and subsequent growth under hydrothermal conditions leading to the formation of an intergrown and distinctive nanocrystalline ZSM-5 shell zeolite. Evidence of the existence of a hierarchical structure was probed by Ar sorption utilising non-local density functional theory (NLDFT) pore size distribution analysis.

为了克服与大烃类催化裂化相关的扩散限制，开发并评估了一种新型核壳分级沸石。大的支链烃在沸石的微孔中遇到用于裂化反应的扩散限制，通过改善分级沸石的结构特性克服了这一限制，从而提高了裂化活性。这将导致失活率、裂化活性的改进和对轻质烃产品的增强的产品选择性。还研究了涉及长链石蜡（十六烷）和高度支化芳烃（1,3,5-TIPB）的链长的影响，以研究微介孔网络的存在对克服扩散限制的影响。

本文研究了分级核壳 BEA@NanoZSM-5 在 1,3,5 三异丙基苯 (1,3,5-TIPB) 和正十六烷 (C ₁₆ )催化裂化中的应用。这种新型分层复合材料是通过对核心 BEA 晶体进行初步接种并随后在水热条件下生长，从而形成共生且独特的纳米晶 ZSM-5 壳沸石来合成的。利用非局部密度泛函理论 (NLDFT) 孔径分布分析，通过 Ar 吸附来探测分层结构存在的证据。