Hierarchically Nanostructured Nickel–Cobalt Alloy Supported on Nickel Foam as a Highly Efficient Electrocatalyst for Hydrazine Oxidation

Abstract

Synthesis of high-performance and nonprecious electrocatalysts for the hydrazine oxidation reaction (HzOR) is of vital importance for the development of direct hydrazine fuel cells (DHFCs) as a viable technology for portable or vehicular applications. Herein, we report a facile synthesis of a Ni foam (NF)-supported Ni–Co alloy catalyst with an urchin-like hierarchical nanostructure using a hydrothermal method combined with two-step calcination. The elaborate design and construction of such a self-supported electrocatalyst can simultaneously optimize the intrinsic activity, afford abundant accessible active sites, ensure good electrical conductivity, and facilitate the mass transfer of reactants and gaseous products. As a consequence, the Ni–Co/NF catalyst prepared under optimal conditions exhibited an exceptionally high activity of 1213 mA cm–2 at +0.30 V versus RHE, a low onset potential of −0.16 V versus RHE for the HzOR, good durability, and nearly 100% selectivity toward the HzOR following the four-electron pathway, outperforming the anode electrocatalysts of DHFCs hitherto reported.