Zhou Jin-Jian, Zhang Meng, Lu Jie, Gu Meng-Xuan, Li Yu-Xia, Liu Xiao-Qin, Sun Lin-Bing
State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
Inorg Chem. 2021 May 3;60(9):6633-6640. doi: 10.1021/acs.inorgchem.1c00438. Epub 2021 Apr 19.
To date, some attempts have been made to synthesize hierarchically porous metal-organic frameworks (HPMOFs), and in most cases, mesopores are formed in microporous frameworks. However, mass transfer and diffusion are still limited in such HPMOFs since micropores connect mesopores and mesopores are noncontinuous. Here, we fabricate a new hierarchical structure through the formation of microporous MOFs within continuous mesoporous channels. Confined space in the as-prepared mesoporous silica-containing template was used to prepare well-dispersed metal precursor of ZnO. The strategy of ligand vapor-induced crystallization was then designed to construct MOFs inside mesoporous channels, in which vapored ligand at elevated temperature diffuses and reacts with metal precursor. Our results indicate that framework isomerism is controllable by adjusting the crystallization conditions. In comparison to their microporous and mesoporous counterparts, the hierarchically porous materials show obviously enhanced adsorption performance on a series of bulky molecules including dye, enzyme, and metal-organic polyhedron.
迄今为止，人们已做出一些尝试来合成具有分级多孔结构的金属有机框架材料（HPMOFs），并且在大多数情况下，中孔是在微孔框架中形成的。然而，由于微孔连接中孔且中孔不连续，此类HPMOFs中的传质和扩散仍然受限。在此，我们通过在连续的中孔通道内形成微孔金属有机框架来构建一种新的分级结构。利用所制备的含介孔二氧化硅模板中的受限空间来制备分散良好的氧化锌金属前驱体。随后设计了配体气相诱导结晶策略，以在中孔通道内构建金属有机框架，其中高温下的气态配体扩散并与金属前驱体反应。我们的结果表明，通过调整结晶条件可控制骨架异构现象。与微孔和中孔对应材料相比，这种分级多孔材料对包括染料、酶和金属有机多面体在内的一系列大分子表现出明显增强的吸附性能。
