High Efficiency CeO₂/CNTs Modified Pt/CNTs Catalysts for Electrochemical Oxidation of Methanol.

The composite catalysts of CeO2/multi-walled carbon nanotubes (CNTs)-Pt/CNTs were prepared. Morphologies of the resulting catalysts were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The results indicated that most of particles have a narrow particle size distribution, and the size distribution followed the Gaussian distribution. The electro-catalytic activity of the CeO2 or CeO2/CNTs modified Pt/CNTs catalysts towards the methanol oxidation reaction was examined by using the cyclic voltammetry (CV) experiments in H2SO4 containing methanol electrolyte. It is found that both catalysts of CeO2-Pt/CNTs and CeO2/CNTs-Pt/CNTs exhibited significantly improved electrochemically active surface area (EAS) and high catalytic activity toward methanol electro-oxidation, as compared with Pt/CNTs. Furthermore, the corresponding CO-stripping test showed that the onset potential and peak maxima in ceria incorporated platinum catalyst were shifted to lower potentials compared to that of the ceria free platinum system. The effects of the loading of CeO2 on CNTs on the electrocatalytic activity of the composite catalysts for methanol oxidation were investigated. We found that the optimal value of ceria loading on CNTs occurred at 40%.