Supportless platinum nanotubes are synthesized by the decomposition of a platinum acetylacetonate vapor within anodic alumina templates at 210 °C. As synthesized, the nanotubes are nanoparticulate aggregates composed of Pt crystallites approximately 3 nm in diameter and with a range of lengths from 1 μm to 20 μm. Annealing treatments result in crystallite growth and morphological evolution of the tubular nanostructures. The oxygen reduction activity of the PtNTs was investigated using the rotating disc electrode method at room temperature. PtNTs annealed at 500 °C exhibited a specific activity of 2084 μA/cm~2_(Pt) at 0.9 V, a value approaching that of polycrystalline Pt. The electrochemical surface area of the annealed structures was found to be quite low, from 5-10 m~2/g, resulting in moderate overall mass activity of up to 177 mA/mg_(pt).
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