(560fy) Impact of Defects on the Decomposition of Chemical Warfare Agent Simulants in Zr-Based Metal Organic Frameworks

Given the threat associated with chemical warfare agents (CWAs), there is a need to develop new materials that can effectively and rapidly detoxify CWAs. It has been shown experimentally that metal organic frameworks (MOFs) containing zirconium secondary building units, such as Zr₆O₄(OH)₄ found in UiO-67 and related MOFs, are highly active for neutralizing the CWA simulant, dimethyl methylphosphonate (DMMP), as well as actual CWAs. It has been assumed that missing linker defects are required for the reaction to proceed in UiO-67. However, it is not known if a single isolated defect is sufficient or if multiple defects are required for facile decomposition of DMMP and CWAs in this material. In this work we use density functional theory calculations to explore the reaction pathways of DMMP on Zr₆O₄(OH)₄–based MOFs. We use full periodic and cluster models to study reaction pathways on UiO-67 multiple defects per secondary building unit. We find that multiple defects can dramatically lower the reaction barrier for DMMP decomposition.