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.