In this study, PtRu nanoparticles deposited on binary carbon supports were developed for use
in direct methanol fuel cells using carbon blacks (CBs) and multi-walled carbon nanotubes
(MWCNTs). The particle sizes and morphological structures of the catalysts were analyzed
using X-ray diffraction and transmission electron microscopy, and the PtRu loading content
was determined using an inductively coupled plasma-mass spectrometer. The electrocatalytic
characteristics for methanol oxidation were evaluated by means of cyclic voltammetry
with 1 M CH3OH in a 0.5 M H2SO4 solution as the electrolyte. The PtRu particle sizes and
the loading level were found to be dependent on the mixing ratio of the two carbon materials.
The electroactivity of the catalysts increased with an increasing MWCNT content,
reaching a maximum at 30% MWCNTs, and subsequently decreased. This was attributed to
the introduction of MWCNTs as a secondary support, which provided a highly accessible
surface area and caused morphological changes in the carbon supports. Consequently, the
PtRu nanoparticles deposited on the binary support exhibited better performance than those
deposited on the single support, and the best performance was obtained when the mass ratio
of CBs to MWCNTs was 70:30.