(70g) Cycled Organophosphate (DMMP) Decomposition over Plasmonic Copper TiO2 Aerogels

Degradation of organophosphates for remediation of environmental pollutants (ex: diazinon, chlorpyrifos) and protection from chemical warfare agents (CWAs, ex: soman, sarin) has spurred research into the development of sorbent and degradative materials. We couple plasmonic copper nanoparticles with mesoporous nanoparticulate metal oxide aerogel architectures (TiO₂, CeO₂) and demonstrate thermal and photo-driven degradation of CWA simulant Dimethyl Methylphosphonate (DMMP). While TiO₂ and CeO₂ adsorb DMMP, thermal and photo-driven degradation functionality is increased by depositing Cu nanoparticles onto the oxide network. Degradation pathways, rates, active lifetime, and product distributions differ tremendously based on the illumination and humidity conditions. Long term stability for DMMP degradation is monitored via in situ DRIFTS over the course of 60 hours under constant dilute DMMP feed. The degree and reversibility of DMMP binding to the composite aerogels was characterized via in situ DRIFTS after multiple regeneration cycles and by ex situ X-ray photoelectron spectroscopy (XPS) pre- and post-DMMP exposure.