Optimizing Hydrazine Activation on Dual‐Site Co‐Zn Catalysts for Direct Hydrazine‐Hydrogen Peroxide Fuel Cells

ABSTRACT

Direct hydrazine‐hydrogen peroxide fuel cells (DHzHPFCs) offer unique advantages for air‐independent applications, but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts. This study reports a novel dual‐site Co‐Zn catalyst designed to enhance the hydrazine oxidation reaction (HzOR) activity. Density functional theory calculations suggested that incorporating Zn into Co catalysts can weaken the binding strength of the crucial N₂H₃* intermediate, which limits the rate‐determining N₂H₃* desorption step. The synthesized p‐Co₉Zn₁ catalyst exhibited a remarkably low reaction potential of −0.15 V versus RHE at 10 mA cm⁻², outperforming monometallic Co catalysts. Experimental and computational analyses revealed dual active sites at the Co/ZnO interface, which facilitate N₂H₃* desorption and subsequent N₂H₂* formation. A liquid N₂H₄‐H₂O₂ fuel cell with p‐Co₉Zn₁ catalyst achieved a high open circuit voltage of 1.916 V and a maximum power density of 195 mW cm⁻², demonstrating the potential application of the dual‐site Co‐Zn catalyst. This rational design strategy of tuning the N₂H₃* binding energy through bimetallic interactions provides a pathway for developing efficient and economical non‐precious metal electrocatalysts for DHzHPFCs.