PdCu/C anode catalysts for the alkaline ascorbate fuel cell

Abstract

In this work, PdCu/C catalysts are used to increase the power output of an alkaline ascorbate fuel cell using an alkaline anion exchange membrane. The alkaline ascorbate fuel cell produces significantly more power than a direct ascorbic acid fuel cell using an acidic cation exchange membrane. However, that alkaline ascorbate fuel cell employs Pd catalyst at the anode. Since addition of Cu to a Pd catalyst results in higher oxidation rates for polyalcohol oxidation in alkaline media, we add Cu to this Pd catalyst to study its impact on ascorbate oxidation in alkaline media. The ascorbate fuel cell maximum power density increases from 53 mW cm−2 when Pd/C is used at the anode to 89 mW cm−2 when Pd28Cu72/C is used. Per mass of Pd, the Pd/C anode produces only 32 mW mg−1 while the Pd28Cu72/C anode produces 194 mW mg−1. Electrochemical analysis of various PdCu/C catalysts shows that the current density after oxidation at −0.4 V for 1 h increases with the addition of greater quantities of Cu to the Pd catalyst, from 0.111 mA cm−2 on Pd/C to 0.757 mA cm−2 on Pd11Cu89/C. This increase in catalytic efficiency when Cu is added to the Pd catalyst is attributed to a combination of the electronic and bifunctional effects.