Controlled synthesis of gold nanosnakes assisted by poly(vinyl pyrrolidone)-sodium dodecyl sulphate aggregations

摘要

Anisotropic single-crystalline gold nanosnakes were synthesised in poly(vinyl pyrrolidone) (PVP)-sodium dodecyl sulphate (SDS) aggregation aqueous solution by reducing HAuCl_4 with PVP without any additional reducing agent. The crystal structures, growth process and the influence of SDS concentrations on the growth of gold nanosnakes have been investigated by X-ray diffraction and transmittance electron microscopy. In this approach, the peculiar structure of PVP-SDS aggregations is indispensable for the asymmetrical formation of gold nanosnakes. Without PVP-SDS aggregations, only long tortuous gold nanobelts were synthesised. When SDS concentration was increased from 3 to 10 mM, gold nanosnakes, nanokites and nanoplates were fabricated. To the best of our knowledge, this is the first report on the SDS-induced shape transformation from snake-like to plate-like at fixed low HAuCl_4 concentration in PVP-SDS aggregation aqueous solutions. Moreover, the gold nanosnakes exhibit excellent electrocatalytic property towards the oxidation of methanol indicating their potential applications in fuel cells, catalysis, biosensing and nanodevices.