Fe Phthalocyanine-Based Catalyst for the Electro-Oxidation of N,N- Diaminourea and Hydrazine and Its Application in an Anion-Exchange Membrane Fuel Cell

Abstract

? The Author(s) 2014.We present a carbon-supported iron phthalocyanine catalyst for the electro-oxidation of N,N-diaminourea (DAU), a hydrazine derivative. This catalyst can oxidize DAU, which is scarcely oxidized by conventional metal electrodes. The onset potential reaches 0.3 V vs. a reversible hydrogen electrode, and the oxidation current of DAU is comparable to that of hydrazine. The activity of Co phthalocyanine was also examined; the Fe phthalocyanine catalyst exhibited a higher oxidation current for DAU than the Co phthalocyanine catalyst. The dependence of the activity on the concentration of DAU suggests that DAU forms a complex with Fe phthalocyanine. Based on this concentration-dependence and an HPLC (high performance liquid chromatography) analysis of DAU hydrolysis, it was shown that hydrolysis of DAU in an electrolyte solution does not significantly affect the electro-oxidation of DAU by a carbon-supported Fe phthalocyanine. We made an anion-exchange membrane fuel cell that incorporates Fe phthalocyanine as an anode catalyst. This cell delivered considerable electricity when DAU was supplied as a fuel (open circuit potential: 0.59 V, short circuit current: 69 mAcm-2 at room temperature).