Node engineering of Zr-Metal Organic Frameworks unlocks potent catalysts for organophosphorus hydrolysis

Organophosphorus chemical warfare agents (CWAs) pose urgent threats to human health and the environment, driving the search for highly efficient catalytic detoxification strategies. Zirconium based metal-organic frameworks (Zr-MOFs) have long been regarded as the most effective catalysts for CWA simulant hydrolysis, owing to the open Lewis acidic sites of their robust Zr6-oxo clusters. This performance established MOF-808 as the accepted state of the art and has remained unsurpassed for the past decade. The Zr6 clusters in MOFs that enable high activity also bind products too strongly, which poisons active sites and restricts turnover, creating an apparent performance ceiling. Herein, we introduce a generalizable node-engineering strategy that achieves Nb substitution of Zr within canonical Zr6 clusters, creating mixed metal Zr6-xNbx clusters rarely realized in MOFs. This approach is demonstrated across four archetypal Zr-MOFs (UiO-66, UiO-68, MOF-808, NU-1000) while preserving framework integrity and porosity. The resulting Zr/Nb-MOFs accelerate phosphoester hydrolysis by up to two orders of magnitude, with MOF-808-Zr/Nb delivering the fastest rates reported to date. Under continuous-flow operation, MOF-808-Zr/Nb maintains superior catalytic activity and durability at concentrations down to 1 ppm. These results establish Nb node engineering as a generic approach for creating next generation heterogeneous catalysts in environmental remediation and chemical defense.