Design strategies and applications of charged metal organic frameworks

As one unique subclass of metal organic frameworks (MOFs), charged MOFs (anionic and cationic MOFs) have attracted extensive attention owing to the strong electrostatic interactions of their charged frameworks. They can serve as interesting cation/anion exchange materials through the exchange of positive/negative counterions in the framework with functional guest species like luminescent or catalytic guest molecules to endow with enhanced performance or unique functions. The inherent charged properties of charged MOFs afford them excellent selectivity in adsorption and separation. This review focuses on the state-of-the-art development of charged MOFs. Firstly, a comprehensive summary of the design strategies and synthetic methods of charged MOFs will be presented. Then, we will discuss how guest ion exchange can enhance the performance of charged MOFs and canvass the potential applications in the fields of gas adsorption and separation, luminescence, sensing, pollutants removal, heterogeneous catalysis and proton conduction. Finally, the critical challenges and future perspectives in this promising field are also highlighted. (C) 2019 Elsevier B.V. All rights reserved.