Nanotwin-Induced Strain Enhances the Catalytic Efficiency of Ni–Zn for Hydrazine Oxidation

The hydrazine oxidation reaction (HzOR) is critical for direct hydrazine fuel cells and presents a promising alternative to the kinetics-sluggish oxygen evolution reaction in water splitting. Engineering catalysts with high-density nanotwin structures has emerged as a compelling strategy to enhance catalytic activity. However, such catalysts have to be explored for HzOR applications. This work reports the successful synthesis of a porous Ni–Zn catalyst featuring high-density coherent nanotwins (NT-Ni-Zn). NT-Ni-Zn supported on Ni foam exhibited exceptionally high catalytic activity and stability toward the HzOR, achieving a current density of 212.4 mA·cm–2 at 0.04 V vs reversible hydrogen electrode and retaining up to 93.9% after 15 h of continuous electrolysis. In addition, hydrazine-assisted water electrolysis using NT-Ni-Zn/Ni foam as both the cathode and anode require only a cell voltage of 70 mV to reach 10 mA cm–2. The exceptional HzOR activity of the Ni–Zn catalyst is attributed to the presence of the nanotwin structure, which promotes a favorable d-band center position and facilitates strong hydrazine binding on the twinned surface. This study provides valuable insights into the development of nanotwin catalysts for HzOR advancement.