Construction of imidazole@defective hierarchical porous UiO-66 and fibrous composites for rapid and nonbuffered catalytic hydrolysis of organophosphorus nerve agents

Abstract

Hydrolytic destruction of toxic organophosphorus nerve agents by metal-organic framework (MOF) catalysts is commonly reliant on bulk water and volatile liquid base, preventing real-world implementation. Poor accessibility to MOF-based active sites in heterogeneous catalysis is also a crucial factor since reactants diffusion is limited by inherently small micropores. To overcome these practical limitations, a ligand-selective pyrolysis strategy was used to construct unsaturated Zr defects and additional mesopores in UiO-66(Zr). Owing to synergistic effect of Zr defects and hierarchical pores, hydrolysis rate constant (k) of nerve agent simulant DMNP (dimethyl 4-nitrophenyl phosphate) on optimal DHP-UiO-30% (defective hierarchical porous UiO-66) is 3.2 times higher than counterpart UiO-30% in N-ethylmorpholine buffer. Encapsulating imidazole (Im) into DHP-UiO-30% affords Im@DHP-UiO, mimicking phosphotriesterase. Im-72@DHP-UiO exhibits rapid DMNP detoxification with 99% conversion in 12 min and initial half-life (t1/2) of 1.8 min in nonbuffered water. As the first example of ‘three-in-one’ detoxifier, Im@DHP-UiO is further integrated onto nonwoven fabric to construct Im@DHP/Fiber, achieving solid-phase detoxification at ambient humidity with t1/2 of 19.6 min and final conversion of 91%. This is comparable to many powdered catalysts in aqueous solution buffered by volatile bases. This unified strategy is critical and viable to efficiently hydrolyze nerve agents in practical settings.