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

Abstract

Ethanol powered direct alcohol fuel cells (DAFCs) have attracted enormous attention as potential power sources for portable electronic devices and transportation due to the much higher energy density than gaseous fuels such as hydrogen and natural gas. On the other hand, the commercialization of DAFCs is limited by the slow electro-kinetics of alcohol oxidation and alcohol crossover through the membrane to the cathode side. The kinetics of alcohol oxidation and oxygen reduction reactions can be improved by operating DAFCs in alkaline medium. Moreover, catalyst materials that are much cheaper and more abundant than Pt can be used for ethanol electro-oxidation and oxygen reduction reactions in alkaline DAFCs. Furthermore, the alkaline DAFCs use alkaline anion exchange membranes (AAEMs) as the electrolyte which protects the electrodes from carbonate formation. Pd has proved to be a good electrocatalyst for ethanol oxidation in alkaline medium, showing higher activity and better steady-state behaviour than Pt. In this work, carbon supported Pd-based nanocatalysts were prepared and evaluated electrochemically for ethanol oxidation in alkaline medium. Carbon supported nanocatalysts were prepared by the chemical reduction method, using the mixture of sodium borohydride and ethylene glycol as the reducing agent.