In situ grown Ni phosphide nanowire array on Ni foam as a high-performance catalyst for hydrazine electrooxidation

Synthesis of high-performance and cost-effective electrocatalysts towards hydrazine electrooxidation is vital to develop the direct hydrazine fuel cell (DHFC) as a viable energy conversion technology. Herein, we report a combined experimental and theoretical study of nickel phosphides (Ni_xP) as promising catalysts for hydrazine electrooxidation. Ni_xP nanowire array supported on a Ni foam (NF) was synthesized by a one-step phosphorization method using hypophosphite as a P-source. Ni₁₂P₅ and Ni₂P phases are observed as the products of the direct phosphorization of commercial NF under the applied conditions with Ni₂P nanoparticles exclusively distributing on the surface of Ni₁₂P₅. The Ni_xP/NF catalyst exhibits a synergetic capabilities of exceptionally high activity, excellent durability and nearly 100% selectivity towards the complete electrooxidation of hydrazine in alkaline condition, which is among the best performance reported on hydrazine electrooxidation catalysts. First-principles calculations have been conducted to gain insight into the catalytic mechanism of Ni phosphides towards hydrazine electrooxidation.