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SEM of Pd-nanotube

Palladium nano-wireWe employ various synthetic techniques in combination with sputtering deposition to form novel nanoscale structures, such as canoes/shells, flowers, tubes and wires with critical nanoscale dimensions. We are currently studying the formation of Pt and Pd nanotubes, nanowires and other nanostructures by combining electrospinning and dc sputtering with the goal of understanding and controlling their morphology, size, and composition — therefore, catalytic activity. The nanostructures have a high surface area to volume ratio, high aspect ratio and high hardness. The dc sputtering deposition of the desired coating on top of the fiber creates a wire with a polymer core surrounded by the metal. Upon air-calcination, the polymer solution and any remaining solvent are eliminated and the various nanostructures are created. Sputtering provides further control of the crystallinity and composition of the nanostructures by dictating the deposition process parameters. The morphology of the structures is studied by scanning electron microscopy, their chemical composition by electron dispersive spectroscopy and their crystallinity by X-ray diffraction, while the catalytic activity is studied by cyclic voltammetry. Applications of these nanostructures as hydrogen sensors is pursued in collaboration with the Nano/Bio Interface Center of U. Penn. This project is supported by an NSF-DMR Partnership for Research and Education in Materials (Grant No. 0353730).