Zirconium hydroxide (Zr(OH)4) shows strong potential for trapping and decomposing chemical warfare agents. VX is especially reactive. H and G are also reactive, but to a lesser extent. However, it is unclear how the reactivity of this promising material is affected by environmental factors such as humidity and trace gases likely to be present under operational conditions. For example, do they enhance reactivity, or do they block surface sites involved in reaction with CW or simulants. If the latter, can the surface be easily regenerated? The work described here combines theory and experiment to elucidate changes in the reactivity of Zr(OH)4 with a common simulant (DMMP) under in operando (ambient) conditions, i.e. in the presence of humidity and background atmospheric gases such as CO2. The theory component relies on DFT and molecular dynamics to model DMMP interactions with slabs of Zr(OH)4. The slabs are allowed to relax, whereupon they spontaneously form surface terminal hydroxyls and water, which are probably involved with the surface reactivity mechanism. Experimentally, thin films of Zr(OH)4 are air-brushed onto prisms for Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR). The prisms are exposed to water, D2O, or isotopically labeled CO2, then DMMP, and interrogated for differences in the surface chemistry. Similar experiments are conducted with Diffuse Reflection IR Spectroscopy (DRIFTS) of Zr(OH)4 powders. We evaluate the role on reactivity of specific surface sites such as under-coordinated Zr, and surface moieties such as bridging and terminal hydroxyls.

DMMP reactivity on zirconium hydroxide under in operando conditions

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.