Laser‐Shocked RuO ₂ –FeCo ₂ O ₄ Interface for Ultralow‐Voltage Hydrazine Splitting and Autonomous Hydrogen Production

Abstract Herein, a hetero‐interfaced RuO ₂ –FeCo ₂ O ₄ composite synthesized via a rapid thermal‐shock strategy using continuous‐wave CO ₂ laser irradiation is reported. The RuO ₂ –FeCo ₂ O ₄ 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 N ₂ H ₄ 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 RuO ₂ optimizes electronic structure and adsorption energies of key intermediates, promoting reaction kinetics. Additionally, a Zn–hydrazine battery with the RuO ₂ –FeCo ₂ O ₄ 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 H ₂ generation. This study underscores the versatility of CO ₂ laser‐induced thermal‐shock synthesis and the synergistic catalytic behavior of the RuO ₂ –FeCo ₂ O ₄ composite for energy‐efficient H ₂ production and hydrazine‐based wastewater remediation.