Electrocatalytic performance comparison of Pt/V and Pd/V electrocatalysts for ethanol oxidation reaction

Abstract

Direct ethanol fuel cells (DEFCs) operate at low temperature, which makes the oxidation and reduction reactions slower, requiring electrocatalysts able to accelerate these reactions. In the present work, commercial Vulcan carbon (V) supported Pt and Pd catalysts were compared as electrocatalysts for ethanol oxidation reaction (EOR) in acidic and alkaline medium, respectively. Cyclic voltammetries obtained in presence of ethanol showing a better catalytic performance for the Pd/V electroctalyst compared to the Pt/V electrocatalyst. The maximum current density related with the EOR in a 1.0 mol L-1 ethanol + 1.0 mol L-1 NaOH solution was 236.9 A g Pd-1 for Pd/V. The better performance of the Pd/V electrocatalyst can be associated with a lower Pd nanoparticles sizes and higher particles dispersion onto the Vulcan carbon surface in the Pd/V electrocatalyst. The onset potential for the EOR was 0.2 V vs. SCE for the Pt/V sample and -0.6 V vs. Hg/HgO for the Pd/V sample.