Polypyrrole nanotube-supported gold nanoparticles: An efficient electrocatalyst for oxygen reduction and catalytic reduction of 4-nitrophenol

Polypyrrole nanotubes (PPyNTs)/Au nanoparticle hybrids were synthesized by using covalently attached imidazolium-type ionic liquids (ILs) as linkers. The approach involves the surface functionalization of PPyNTs with ILs, anion-exchange with Au precursor and followed by the reduction of metal ions to produce the Au nanoparticles. The surface functionalized ILs on the PPyNTs surface play an important role in the formation of Au/ILs/PPyNTs hybrids. The synthesized Au nanoparticles supported on the ILs/PPyNTs surface have a smaller particle size and better dispersion than those on pristine PPyNTs surface. The morphology and optical properties of the produced nanohybrids were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectrometer, X-ray diffraction (XRD) and UV-vis spectroscopy. The catalytic performances of Au/ILs/PPyNTs hybrids were evaluated for both the electrocatalytic oxygen reduction and catalytic reduction of 4-nitrophenol in the presence of NaBH4. The results revealed that the Au/ILs/PPyNTs hybrids are effective electrocatalysts for dioxygen reduction and for the reduction of 4-nitrophenol. (C) 2011 Elsevier B.V. All rights reserved.