Preparation and electrochemical properties of MnO2 nanosheets attached to Au nanoparticles on carbon nanotubes.

A wet chemical route for the preparation of MnO(2) nanosheet/Au nanoparticle/MWNT hybrid materials is developed. The Au nanoparticles are prepared by reducing AuCl(4)(-) with citrate and attached to thiol-modified MWNTs. Owing to the reducing property and the binding ability to Mn-containing species of capping agents surrounded the Au nanoparticles, the MnO(2) nanosheets are formed on the surface of Au nanoparticles. The ternary nanocomposites of MnO(2)/Au/MWNT have been characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and FT-IR spectroscopy. The affiliation of MnO(2) nanosheets into the hybrids remarkably enhances the electrocatalytic performance of Au nanoparticle/MWNT towards the oxygen reduction reaction. The specific capacitance of the ternary hybrids is also increased dramatically comparing with that of Au/MWNT.