Energy‐Saving Electrolytic Hydrogen Generation: Ni₂P Nanoarray as a High‐Performance Non‐Noble‐Metal Electrocatalyst

It is highly attractive but challenging to develop earth-abundant electrocatalysts for energy-saving electrolytic hydrogen generation. Herein, we report that Ni₂ P nanoarrays grown in situ on nickel foam (Ni₂ P/NF) behave as a durable high-performance non-noble-metal electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The replacement of the sluggish anodic oxygen evolution reaction with such the more thermodynamically favorable HzOR enables energy-saving electrochemical hydrogen production with the use of Ni₂ P/NF as a bifunctional catalyst for anodic HzOR and cathodic hydrogen evolution reaction. When operated at room temperature, this two-electrode electrolytic system drives 500 mA cm^-2 at a cell voltage as low as 1.0 V with strong long-term electrochemical durability and 100 % Faradaic efficiency for hydrogen evolution in 1.0 m KOH aqueous solution with 0.5 m hydrazine.