Decomposition of contaminants using photochemically active nanoparticles.

Abstract

The decomposition of hazardous biological (viruses and bacteria) and non-biological (e.g., nerve agents, H 2 S, HCN) compounds can be realized using a new class of photochemically active nanoparticles that have been fine-tuned for decontamination applications. Several metal oxides (TiO 2 , ZnO, Fe 2 O 3 , WO 3 ) have demonstrated the ability to destroy contaminants upon exposure to UV light. However, to make them of practical use, improving their activity is necessary. These materials work by photoactivating water and oxygen to create highly reactive species (e.g., OH•) that readily decompose the compounds described above. This project researched developing a new class of highly photoactive materials by combining: scientific investigation into the mechanisms of photocatalysis, advanced techniques to synthesize nanoparticles, and testing the ability of these materials to destroy simulants of CBW/NTA agents. In-situ microscopy established that the photocatalytic activity occurred uniformly over a TiO 2 surface. A large number of nanomaterials were synthesized and evaluated. Two main nanoparticle synthesis routes were explored: (A) solution routes and (B) solvothermal routes. Specialized test equipment was designed and constructed. We discovered a large number of doped-TiO 2 materials that were less active than un-doped TiO 2 . However, our testing showed that several materials synthesized were more catalytically active than any un-doped material, including newly commercialized TiO 2 nanoparticles.