Outer-Sphere Modulation of Zr-based Metal-Organic Frameworks for Nerve Agent Detoxification

Organophosphorus nerve agents with extreme toxicity have been still used in the past few years. Recent advances in Zr-based metal-organic framework (MOF) catalysts have emerged as promising platforms for efficient nerve agent degradation, based on highly active Zr6 nodes and further enhancement of the activity via ligand functionalization. However, catalytic optimization confined to proximal modulation, where functional groups often interact with substrates, and thus impacts of outer-sphere modulation are still veiled. Here, we present a strong influence of outer-sphere modulation in optimizing the catalytic activity of Zr-based MOFs for nerve agent simulant degradation. A series of Zr-based MOFs with porphyrin ligands was prepared by substituting porphyrin cores with different metal ions (Al, Cu, Co, and Fe). Notably, the Fe-substituted MOF exhibited superior hydrolytic performance against a nerve agent simulant, achieving a half-life of just 5 minutes at 1 mol% catalyst loading. This performance is comparable to the most active Zr-based MOF catalysts reported to date. Our findings highlight a new perspective for optimizing catalytic metal nodes of Zr-based MOF via outer-sphere modulation and provide a new paradigm for engineering high-performance MOFs for chemical defense.