Effect of Adsorbed Water and Surface Hydroxyls on the Hydrolysis of VX, GD, and HD on Titania Materials: The Development of Self-Decontaminating Paints

Abstract

Titania materials such as anatase (TiO2), nanotubular titania (NTT), and nanocrystalline titania (nTiO2) exhibit extremely short half-lives for VX, provided adequate surface-adsorbed water is present. The effect of coadsorbed water on the hydrolytic activity of these materials toward VX, GD, and HD was assessed to select the most promising candidate for study in self-decontaminating paints and coatings. The best candidate is nTiO2, primarily chosen for its extremely short VX half-life at quite high water-content. For the most part, imbedding nTiO2 into various coatings negatively impacts its reactivity. A notable exception is observed for the case of HD and nTiO2/Wax (a paint simulant), where a somewhat shorter half-life is observed compared to the nascent nTiO2 powder. However, encrusting a painted surface with nTiO2 powder, leaving it partly exposed rather than wholly imbedded, results in improved reactivity.