AMMONIA SENSING OF ELECTROSPUN V2O5 COMPOSITE MATERIALS: SYNTHESIS, CHARACTERIZATION AND ELECTRICAL PROPERTIES

Semiconductor transition metal oxides with d0 electron configuration, such as V2O5, containing active sites able to adsorb gaseous molecules and catalyze reactions on their surface, show promising properties as sensing elements in resistive gas sensors. To maximize the surface area and to improve the sensing efficiency, divanadium pentoxide nanostructures such as nanotubes, nanorods and nanobelts have been synthesized by different methods, such as reverse micelle, sol-gel and chemical vapor deposition. Recently, vanadium oxide-based fibers were also synthesized by the electro-spinning method combined with sol-gel processing [1]. In the present work, we report efforts made in developing Pt-doped vanadium oxide/polymer composites for ammonia sensing in air. Taking as reference vanadium oxide/polyvinyl acetate (V2O5/PVAc) fibers [1], it has been undertaken a study to investigate the influence of the nature of polymer and platinum on the sensing performances. A simple sol-gel based electrospinning method has been applied for the synthesis of platinum-vanadium oxide/polyvinyl acetate (Pt-V2O5/PVAc), vanadium oxide/polyvinyl pyrrolidone (V2O5/PVP) and platinum-vanadium oxide/polyvinyl pyrrolidone (Pt-V2O5/PVP) fibers for gas sensing applications. The pure metal oxide phase has been subsequently obtained by removing the polymer through annealing at high temperature of the composite fibers in air. The "as-spun" fibers and related products of annealing have been widely studied to characterize their morphological and microstructural properties by XRD, FTIR, XPS and SEM investigations. The application of the produced fibers as high performance ammonia resistive sensors has been demonstrated.