Li Hao, Qin Ze, Yang Xianfeng, Chen Xiao, Li Yingwei, Shen Kui
Guangdong Provincial Key Laboratory of Fuel Cell Technology, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China.
Analytical and Testing Centre, South China University of Technology, Guangzhou, Guangdong 510640, China.
ACS Cent Sci. 2022 Jun 22;8(6):718-728. doi: 10.1021/acscentsci.1c01563. Epub 2022 May 6.
The nanoarchitecture engineering of metal-organic frameworks (MOFs) is a fascinating but intellectually challenging concept that opens up avenues for both tailoring the properties of MOFs and expanding their applications. Herein, we report the confined growth of ZIF-8 single crystals in a three-dimensionally ordered (3DO) macroporous polystyrene replica and reveal that their growth patterns, morphologies, and nanoarchitectures can be highly engineered using the concentration of the precursor. Impressively, the favorable in situ confined growth enables the successful fabrication of 3DO sphere-assembled ZIF-8 single crystals or 3DO single-crystalline ZIF-8 sphere arrays when a low- or high-concentration precursor solution, respectively, is used as the feedstock. Furthermore, our strategy can be extended to the preparation of other 3DO MOF single crystals, including ZIF-67 and HKUST-1, with similar controllable hierarchical nanoarchitectures. With the successful preparation of a series of diameter-tunable ZIF-8 single-crystalline spheres, we further unravel their interesting size-performance relationship in the Knoevenagle reaction between benzaldehyde and malononitrile, wherein the smallest spheres show the fastest first-order reaction kinetics. This study not only develops a general strategy for engineering the nanoarchitectures of MOF single crystals but also provides fundamental knowledge of the mechanism for the growth of hierarchical single crystals under confined spaces.
金属有机框架材料（MOFs）的纳米结构工程是一个引人入胜但极具智力挑战的概念，它为定制MOFs的性质和扩展其应用开辟了道路。在此，我们报道了ZIF-8单晶在三维有序（3DO）大孔聚苯乙烯复制品中的受限生长，并揭示了它们的生长模式、形态和纳米结构可以通过前驱体的浓度进行高度调控。令人印象深刻的是，当分别使用低浓度或高浓度的前驱体溶液作为原料时，这种有利的原位受限生长能够成功制备出3DO球形组装的ZIF-8单晶或3DO单晶ZIF-8球体阵列。此外，我们的策略可以扩展到制备其他具有类似可控分级纳米结构的3DO MOF单晶，包括ZIF-67和HKUST-1。通过成功制备一系列直径可调的ZIF-8单晶球体，我们进一步揭示了它们在苯甲醛和丙二腈的Knoevenagle反应中有趣的尺寸-性能关系，其中最小的球体表现出最快的一级反应动力学。这项研究不仅开发了一种工程化MOF单晶纳米结构的通用策略，还提供了在受限空间内分级单晶生长机制的基础知识。
