Magnetron sputtering of platinum nanoparticles onto vertically aligned carbon nanofibers for electrocatalytic oxidation of methanol

The electrochemical activities of Pt-sputtered electrodes based on vertically aligned carbon nanofibers (Pt/VACNEs) directly grown on the carbon paper are investigated. Different Pt loading (0.01 mg cm(-2), 0.025 mg cm(-2) and 0.05 mg cm(-2)) electrodes are developed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that the Pt nanoparticles are homogeneously dispersed on the surface of vertically aligned carbon nanofibers. TEM and X-ray diffraction (XRD) results reveal the Pt nanoparticles diameter increase with increasing Pt loading. The Pt/VACNFs electrodes show good electrochemical active surface area, methanol oxidation peak current density and CO tolerance. The electrochemical catalyst activities weaken as the diameter grows larger. Compared to common electrodes prepared by commercial catalyst in a conventional ink-process, the performance improvement suggests that unique structure of Pt/VACNFs electrode ensures the electronic pathway and Pt nanopartides exposed to three-phase boundary, which leads to a significant improvement of the Pt utilization and a potential application in direct alcohol fuel cells. (C) 2011 Elsevier Ltd. All rights reserved.