Direct hydrazine fuel cells have been attracting much interest owing to their high theoretical standard equilibrium potential (1.56 V) and high-power density (5400 W h L−1). The electrocatalyst is the pivotal component for the fuel cells, and low-cost, earth-abundant catalysts with high activity and durability are highly desired. Metal-metal oxide core-shell heterostructures have exhibited outstanding performances in many realms, especially in catalysis, due to the enriched phase interfaces and the strong metal/metal oxide interactions. Herein, Co@CoO core-shell heterostructures with a crystalline Co core and an amorphous CoO shell have been prepared by a simple solution reduction process and shown to be effective catalysts for the electro-oxidation of hydrazine in alkaline media. The core-shell structure was confirmed by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The electrochemical evaluation was carried out in a typical three-electrode system. The synergistic effect between the metallic Co core and amorphous CoO shell renders a high catalytic activity with a small onset potential of −1.10 V vs Ag/AgCl and a high current density of 67.6 mA cm−2 at −0.90 V vs Ag/AgCl in 0.5 M N2H4 with 1.0 M KOH. The electrocatalytic performance of the Co@CoO catalyst is comparable to those of the state-of-the-art catalysts.

Crystalline-amorphous Co@CoO core-shell heterostructures for efficient electro-oxidation of hydrazine

255th National Meeting (2018)

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