Laser-Shocked RuO₂-FeCo₂O₄ Interface for Ultralow-Voltage Hydrazine Splitting and Autonomous Hydrogen Production

Herein, a hetero-interfaced RuO₂-FeCo₂O₄ composite synthesized via a rapid thermal-shock strategy using continuous-wave CO₂ laser irradiation is reported. The RuO₂-FeCo₂O₄ composite exhibits outstanding bifunctional activity, with a low overpotential of 50 mV for the hydrogen evolution reaction (HER) and an ultralow oxidation potential of -21 mV versus RHE for the hydrazine oxidation reaction (HzOR) at 10 mA cm^-2. Consequently, an overall hydrazine splitting (OHzS) employing this composite requires merely 0.109 V at 10 mA cm^-2, while maintaining excellent long-term stability and complete N₂H₄ degradation. Comprehensive in situ and ex situ analyses reveal that surface reconstruction plays a critical role in enhancing the catalytic performance of HER and HzOR. Density functional theory calculations further confirm that RuO₂ optimizes electronic structure and adsorption energies of key intermediates, promoting reaction kinetics. Additionally, a Zn-hydrazine battery with the RuO₂-FeCo₂O₄ cathode achieves a high energy efficiency of 91% and sustained operation over 200 h. Integration of this battery with the OHzS electrolyzer establishes a fully autonomous platform for continuous H₂ generation. This study underscores the versatility of CO₂ laser-induced thermal-shock synthesis and the synergistic catalytic behavior of the RuO₂-FeCo₂O₄ composite for energy-efficient H₂ production and hydrazine-based wastewater remediation.