In Situ Formation of Three-Dimensional Uniform Pt/Carbon Nanotube Nanocomposites from Ionic Liquid/Carbon Nanotube Gel Matrix with Enhanced Electrocatalytic Activity toward Methanol Oxidation

We report here a new electrochemical method for in situ deposition of Pt nanoparticles onto multiwalled carbon nanotubes (MWNTs) to form a three-dimensional uniform Pt/MWNT nanocomposite with excellent electrocatalytic activity toward the oxidation of methanol, by taking advantage of the good solubility of MWNTs and chloroplatinic acid (H2PtCl6) into ionic liquids (i.e., BmimPF(6)) to form a homogeneous and electronic conductive gel matrix. The gel is prepared by first dissolving H2PtCl6 into ionic liquids and then grinding the ionic liquids with MWNTs. The formation of the nanocomposite is accomplished by the reduction of the H2PtCl6 precursor onto MWNTs, both in the gel matrix. Scanning electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry results reveal that the good homogeneity and conductivity of the prepared gel matrix substantially results in the formation of a three-dimensional nanocomposite, in which Pt nanoparticles are homogeneously deposited onto MWNTs in the gel matrix. Voltammetric study with the as-prepared Pt/MWNT nanocomposite indicates that the nanocomposite processes an enhanced electrocatalytic activity toward the oxidation of methanol, as compared with the Pt/MWNT nanocomposite prepared with the conventional electrochemical method by the reduction of the H2PtCl6 precursor in the Solution phase Onto MWNTs confined onto conducting Substrate. The strategy demonstrated here is facile, cost-effective. and environmentally benign and may be versatile for the preparation of three-dimensional MWNT-based nanocomposites with other kinds of metal nanoparticles with excellent properties.