Agent Degradation via Catalytic and Photocatalytic Reactions on Surfaces and in Organized Assemblies

Research pursued under Contract no. DAJA45-87-C-005 has concentrated on the catalytic and photocatalytic destruction of simulants for V-agents in oxide semiconductor systems, in particular titanium dioxide. Near UV irradiation of TiO2 semiconductor particles suspended in solution generates electrons and holes in the conduction and valence bands, respectively, free charge carriers that are highly reactive reductants and oxidants. We have previously shown that all the simulants employed underwent complete oxidation and mineralization in the presence of light activated TiO2. In addition, surface adsorbed hydroxide and peroxide ions act as powerful nucleophiles promoting ester hydrolysis. These thin films were formed by a sol-gel type procedure yielding layers with a specific surface texture and a high porosity, the roughness factor being 100 to 200. Hydrolysis and oxidative decontamination were tested with agents deposited on the surface which, due to the fractal-type pore geometry, shows a very high capacity for uptake of adsorbent.