Layer-by-Layer Photocatalytic Assembly for Solar Light-Activated Self-Decontaminating Textiles

Novel photocatalytic nanomaterials that can be used to functionalize textiles, conferring to them efficient solar-light-activated properties for the decontamination of toxic and lethal agents, are described. Textiles functionalized with one-dimensional (1D) SnS₂-based nanomaterials were used for photocatalytic applications for the first time. We showed that 1D SnS₂/TiO₂ nanocomposites can be easily and strongly affixed onto textiles using the layer-by-layer deposition method. Ultrathin SnS₂ nanosheets were associated with anatase TiO₂ nanofibers to form nano-heterojunctions with a tight interface, considerably increasing the photo-oxidative activity of anatase TiO₂ due to the beneficial interfacial transfer of photogenerated charges and increased oxidizing power. Moreover, it is easy to process the material on a larger scale and to regenerate these functionalized textiles. Our findings may aid the development of functionalized clothing with solar light-activated photocatalytic properties that provide a high level of protection against chemical warfare agents

Chemistry of NO_<i>x</i> on TiO₂ Surfaces Studied by Ambient Pressure XPS: Products, Effect of UV Irradiation, Water, and Coadsorbed K⁺

Self-cleaning surfaces containing TiO₂ nanoparticles have been postulated to efficiently remove NO_<i>x</i> from the atmosphere. However, UV irradiation of NO_<i>x</i> adsorbed on TiO₂ also was shown to form harmful gas-phase byproducts such as HONO and N₂O that may limit their depolluting potential. Ambient pressure XPS was used to study surface and gas-phase species formed during adsorption of NO₂ on TiO₂ and subsequent UV irradiation at λ = 365 nm. It is shown here that NO₃^–, adsorbed on TiO₂ as a byproduct of NO₂ disproportionation, was quantitatively converted to surface NO₂ and other reduced nitrogenated species under UV irradiation in the absence of moisture. When water vapor was present, a faster NO₃^– conversion occurred, leading to a net loss of surface-bound nitrogenated species. Strongly adsorbed NO₃^– in the vicinity of coadsorbed K⁺ cations was stable under UV light, leading to an efficient capture of nitrogenated compounds