Tailoring Multiple Sites of Metal–Organic Frameworks for Highly Efficient and Reversible Ammonia Adsorption
Zhenzhen Wang, Zhiyong Li, Xia‐Guang Zhang, Qingchun Xia, Huiyong Wang, Chenlu Wang, Yanlei Wang, Hongyan He, Yang Zhao, Jianji Wang
Abstract
The structural diversity and designability of metal–organic frameworks (MOFs) make these porous materials a strong candidate for NH3 uptake. However, to achieve a high NH3 capture capacity and good recyclability of MOFs at the same time remains a great challenge. Here, a multiple-site ligand screening strategy of MOFs is proposed for highly efficient and reversible NH3 uptake for the first time. Based on the optimized DFT results for various possible ligands, pyrazole-3,5-dicarboxylate with multiple sites was screened as the best ligand to construct robust MOF-303(Al) with Al3+. It is experimentally found that the NH3 adsorption capacity of MOF-303(Al) is as high as 19.7 mmol g–1 at 25.0 °C and 1.0 bar, and the NH3 capture is fully reversible and no clear loss of capture capacity is observed after 20 cycles of adsorption–desorption. Various spectral studies verify that the superior NH3 capacity and excellent recyclability of MOF-303(Al) are mainly attributed to the hydrogen bonding interactions of NH3 with multiple sites of MOF-303(Al).