Journal of Power Sources, Vol.193, No.2, 462-469, 2009
A proper amount of carbon nanotubes for improving the performance of Pt-Ru/C catalysts for methanol electro-oxidation
This study aims to improve the performance of the anode catalyst in a direct methanol fuel cell by using carbon black (XC) and mesoporous carbon (MC) as supporting materials for preparing Pt-Ru/XC and Pt-Ru/MC catalysts. This study investigates the effect of adding different amounts of bare carbon nanotubes (CNTs) or carbon nanotubes impregnated with Pt and Ru (abbreviated as Pt-Ru/CNT, containing 10 wt.% Pt and Ru) to the prepared catalysts. Experimental results reveal that 10 wt.% Pt-Ru/C with carbon black and mesoporous carbon prepared by the multiple impregnation method had smaller Pt-Ru grain sizes and a better dispersion or carbon supports due to low precursor concentrations in each impregnation. These, in turn, achieved better electro-catalytic performance for methanol oxidation. Adding CNTs or Pt-Ru/CNT to Pt-Ru/XC and Pt-Ru/MC obviously improves their electro-catalytic characteristics. The appropriate amounts of bare CNT and Pt-Ru/CNT added to Pt-Ru/XC and Pt-Ru/MC catalysts are 5% and 20%, respectively. The resulting catalysts (both containing 10 wt.% Pt and Ru) produce activities similar to those of the E-TEK Pt-Ru/C catalyst containing 20 wt.% Pt and Ru. (c) 2009 Elsevier B.V. All rights reserved.
Keywords:Methanol electro-oxidation;Pt-Ru catalysts;Carbon nanotubes;Mesoporous carbon;Direct methanol fuel cell