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

Abstract

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.