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

Authors: 
Pennington, A. - Presenter, Federal Energy Management Program
DeSario, P. A., Naval Research Laboratory
Pitman, C. L., NRC Postdoctoral Associate
Brintlinger, T. H., Naval Research Laboratory
Pietron, J. J., Naval Research Laboratory
Stroud, R., Naval Research Laboratory
Rolison, D., Naval Research Laboratory
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.