Carbon Nanotubes Generated from Template Carbonization of Polyphenyl Acetylene as the Support for Electrooxidation of Methanol

Abstract

The template carbonization of polyphenyl acetylene yielded well aligned, cylindrical, mono disperse carbon nanotubes (CNT), which are effectively utilized to load Pt, Pt−Ru, and Pt−WO3 nano particles. The nanoparticles are effectively dispersed inside the tube with the particle sizes of around 1.2, 1.6, and 10 nm for Pt, Pt−Ru, and Pt−WO3, respectively. The electrochemical surface area of the CNT-based electrode was higher compared to the Vulcun XC 72R carbon, graphite, and glassy carbon (GC) electrodes. The X-ray photoelectron spectroscopic measurements revealed that the Pt and Ru are in metallic state and W is in +VI oxidation state. The higher activity of GC/CNT−Pt−WO3−Nafion for methanol oxidation compared to GC/CNT/Pt−Ru−Nafion and GC/CNT/Pt−Nafion suggests the better utilization of the catalytic particles. The stability of the electrode for methanol oxidation polarized at +0.6 V follows the order of GC/CNT/Pt−Ru−Nafion > GC/CNT/Pt−WO3 > GC/CNT/Pt−Nafion, and for the electrodes polarized at +0.4 V, the order is GC/CNT/Pt−WO3−Nafion > GC/CNT/Pt−Ru−Nafion > GC/CNT/Pt−Nafion. The differences in the stability possibly suggest the better tolerance of the adsorbed species of methanol oxidation for the GC/CNT/Pt−WO3−Nafion electrode (when it is polarized at +0.4 V).