Boosting electrocatalytic hydrazine oxidation at single-crystalline Ni nanosheets with embedded NiZn

Hydrazine oxidation reaction (HzOR) plays a crucial role in direct hydrazine fuel cells and holds promise for replacing the kinetics-sluggish oxygen evolution reaction in splitting water. While Ni–Zn alloys exhibit exceptional activity for HzOR, their synthesis under mild conditions remains a challenge. Herein, a Ni–Zn nanosheet catalyst with NiZn inclusion was prepared on Ni foam by controllable chemical etching together with ethylene glycol reduction. X-ray diffraction and transmission electron microscopy confirmed the single-crystalline nature and the presence of intermetallic NiZn. The strong interaction between Ni and ZnO, along with defects, facilitated the formation of this intermetallic compound. The Ni–Zn/Ni foam exhibits remarkable catalytic activity (214.3 ​mA ​cm−2 at 0.1 ​V) and durability (87.8 ​% retention after 24 ​h) towards hydrazine electrooxidation, thanks to the combined benefits of intermetallic NiZn, mesoporous nanosheets, microscopic defects, single-crystalline characteristics, and a coherent Ni–NiZn interface. This study provides a new method for designing highly active Ni–Zn electrocatalysts for HzOR.