Current chemical warfare (CW)-protection strategies use adsorbent materials to minimize the throughput of CWAs, but these materials have limited capacity and may not degrade agents to nontoxic products. Multifunctional composites that couple high-capacity -adsorbents with catalytic nanoparticles offer a promising route towards organophosphorus (OP) compound degradation. Many metal oxides are good low-temperature adsorbents for OP compounds, but they typically display modest reactivity towards OP compounds and non-catalytic degradation poisons active/adsorption sites. We couple anatase TiO₂ aerogels with supported Cu nanoparticles (Cu/TiO²) and characterize the adsorption and degradation of CW simulants and live agents under dark and illuminated conditions. The TiO₂ aerogel provides a high surface area for CW agent/simulant adsorption as well as a mesoporous void network to facilitate mass transport. The high interfacial contact between Cu nanoparticles and the TiO₂ aerogel stabilizes a higher fraction of low-valent Cu^0/+1 in the Cu nanoparticles relative to what is achieved by depositing Cu nanoparticles on non-networked nanoparticulate TiO₂ supports. While TiO₂aerogels alone display only modest CWA degradation activity, the Cu/TiO₂ aerogels are much more active for agent degradation. The Cu/TiO₂ aerogels also display enhanced agent degradation under visible illumination conditions, indicating that the surface plasmon resonance of Cu nanoparticles is initiating agent degradation chemistry. We benchmark the activity of Cu/TiO₂ aerogels relative to Au/TiO₂ aerogels to assess Cu as a onprecious alternative to Au nanoparticles. A fundamental understanding of the ability of these materials to degrade organophosphorous compounds under these controlled laboratory conditions is an important first step in the development of new degradation strategies for field-decontamination.

Jeremy Pietron

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