近日，复旦大学孙正宗团队研究了表面Al位富集的外延双层MWW沸石。2025年10月28日出版的《美国化学会志》发表了这项成果。

在均匀结晶的微孔内，沸石利用嵌入的酸中心选择性地调整化学键。分子筛的催化性能取决于其酸强度和酸丰度、可及性和耐久性，这是在单一分子筛结构中难以实现的。双层沸石具有较短的扩散距离和优良的层间支撑框架，通过共价键相互连接。其表面铝位点对大体积分子催化具有显著的可及性优势。

在这项工作中，研究组证明了直接合成双层MWW （BL-MWW）分子筛，以六方氮化硼（h-BN）为外延模板种子，六亚亚胺（HMI）和环己酮（CYCL）为双有机结构导向剂。BL-MWW分子筛平均厚度为5nm，具有共价层间支撑结构。在CYCL分子和钠离子的协同作用下，BL-MWW的外表面富集了T2铝的强酸性位点，富集量高达11.1%，超过了内部的6.3%。在800°C水热处理下，BL-MWW结构保持完整，在不同官能团大分子的烷基化转化和耐久性以及大分子和聚合物的裂解方面都优于同类沸石。

附：英文原文

Title: Epitaxial Bilayer MWW Zeolite with Enriched Surface Al Sites

Author: Hongbin Li, Yajie Wang, Kexin Yan, Guolong Sun, Xian Li, Haoyu Li, Junxiang Shu, Xueqian Kong, Xiao Chen, Hongbin Zhang, Changlin Zheng, Yi Tang, Zhengzong Sun

Issue&Volume: October 28, 2025

Abstract: Inside the uniform and crystalline micropores, zeolite utilizes embedded acid centers to selectively tailor chemical bonds. The catalytic performance is determined by the acid strength and abundance, accessibility, and endurance, which are challenging to realize in a single zeolite structure. Bilayer zeolite has a short diffusion distance and excellent interlayer supportive frameworks interconnected via covalent bonds. Its surface aluminum sites display significant accessibility advantages for bulky molecular catalysis. In this study, we demonstrate a direct synthesis of bilayer MWW (BL-MWW) zeolite, using hexagonal boron nitride (h-BN) as the epitaxial template seed, and hexamethylenimine (HMI) and cyclohexanone (CYCL) as the dual organic structure-directing agents. The BL-MWW zeolite displays an average of 5 nm thickness and a covalent interlayer supportive structure. Synergistically coordinated by the CYCL molecule and sodium ion, the external surface of BL-MWW exhibits an enrichment up to 11.1% of the stronger acid sites of T2 aluminum, surpassing the 6.3% of the internal ones. The BL-MWW structure remains intact with 800 °C hydrothermal treatment and outperforms its peer zeolites in both conversion and endurance for alkylation of bulky molecules with different functionalities as well as cracking of macromolecules and polymers.

DOI: 10.1021/jacs.5c11868

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c11868