Insight into α- and β-Ni(OH)2 in Electrochemical Hydrazine Oxidation in Alkaline Media

Abstract

Recently, direct hydrazine fuel cell (DHFC) has been intensively studied due to its advantages in terms of the high theoretical potential, the high power density with non-precious metal. However, the study of the catalytic activity of Ni in hydrazine oxidation is still demanded for commercialization. In this study, Ni/C catalyst with dominant α-Ni(OH)2 or β-Ni(OH)2 was synthesized by polyol reduction and by aging. The distinction for α- and β-Ni(OH)2 of the prepared Ni/C were observed by physicochemical and electrochemical analysis. The catalytic activity of hydrazine oxidation by different structure of α- and β-Ni(OH)2 was investigated in practical fuel cell system. As a result, α-Ni(OH)2 with intercalated H2O molecules exhibited the outstanding cell performance. Based on the results, it was demonstrated that α-Ni(OH)2 serves as active structure in alkaline DHFC.