Computational Screening of Metal-Organic Framework-Supported Single-Atom Transition-Metal Catalysts for the Gas-Phase Hydrolysis of Nerve Agents

Recent studies have suggested that the gas-phase hydrolysis of nerve agents by Zr-based metal-organic frameworks (MOFs) may be limited by product inhibition resulting from strong bidentate binding of the hydrolysis products to the Zr₆-nodes. A potential method to avoid this problem is to deposit single-atom catalysts on the nodes so that the products bind in a more favorable monodentate mode. Such catalytic active sites can be characterized with atomic precision, enabling detailed computational mechanistic studies. Thus, we used density functional theory to perform a comprehensive screening of single-atom transition-metal catalysts, in varying oxidation states, deposited on NU-1000 nodes for the gas-phase hydrolysis of the nerve agent sarin. By calculating the complete reaction pathways for M-NU-1000 systems, we discovered that the highest reaction barrier varies between catalysts, highlighting the need to consider more than a single reaction step when screening a large number of diverse materials. The single-metal catalysts are predicted to exhibit lower product desorption energies than unfunctionalized NU-1000. By comparing their relative turnover frequencies using the energetic span model, we identified several catalysts that are predicted to be more active than the parent MOF for this reaction. Finally, we explored periodic trends and molecular descriptors for their effect on catalytic activity.