Covalently Bound MOF/COF Aerogels as Robust Catalytic Filters for Rapid Nerve Agent Decomposition

Abstract

Metal-organic frameworks (MOFs) show promising results in various fields, such as gas separation and catalysis, but they face limitations due to problems associated with their low processability. This study addresses these challenges by utilizing postsynthetic modification (PSM) of NH2-UiO-66 and NH2-MOF-808 with 1,3,5-benzene tricarbaldehyde (BTCA) to form hybrid aerogels consisting of MOF-loaded covalent organic framework (COF). BTCA-modified MOF nanoparticles via imine bond formation were confirmed by 1H NMR, FTIR, and solid-state 13C NMR spectroscopies. MOF/COF composites were analyzed via TGA, PXRD, BET, and solid-state 13C NMR, showing retained crystallinity and increased porosity in comparison to the sum of the individual components. Moreover, improved aerogel mechanical properties and increased MOF loading of up to 75 wt % were achieved for covalently bound aerogels. Hybrid aerogel composites were successfully utilized as catalytic filters for the decomposition of nerve agent simulant and pesticide dimethyl-4-nitrophenylphosphate (DMNP), avoiding secondary pollution associated with MOF powder catalysis.