Carbon supported Pd-Ni and Pd-Ru-Ni nanocatalysts for the alkaline direct ethanol fuel cell (DEFC)

Abstract

Carbon supported Pd-Ni and Pd-Ru-Ni nanocatalysts were prepared by the chemical reduction method, using sodium borohydride and ethylene glycol mixture as the reducing agent. The catalytic activity towards ethanol electro-oxidation in alkaline medium was studied by cyclic voltammetry. The current density obtained for the electro-oxidation was affected by varying ethanol concentration between 0.25 and 4 M. Raising ethanol concentration up to 3 M increased the coverage of the adsorbed ethoxy (CH3COads) species on the nanocatalyst surface, thus yielding an increase in current density. Pd-Ni/C displayed better electrocatalytic activity than Pd/C and Pd-Ru-Ni/C nanocatalysts. Transmission electron microscopy results showed that Pd-Ni and Pd-Ru-Ni nanoparticles were uniformly dispersed on carbon support. The average particle size of Pd-Ni was 7 ± 0.8 nm in diameter while for Pd-Ru-Ni was 6 ± 0.5 nm. The nanocatalysts performance in alkaline DEFC was evaluated under passive state at room temperature (25 °C).