A research team from Gyeongsang National University has developed a pulsed-laser-fabricated ruthenium@carbon catalyst that dramatically lowers the energy barrier for hydrogen production while simultaneously degrading toxic hydrazine pollutants. Published in eScience with DOI 10.1016/j.esci.2025.100408, this breakthrough addresses two critical challenges in the transition to sustainable energy systems: the high energy costs of conventional hydrogen production and the environmental hazards posed by industrial pollutants.
The catalyst consists of uniform ruthenium nanospheres encapsulated within graphitic carbon shells, with the optimized Ru@C-200 configuration achieving exceptional performance metrics. It requires only 48 mV overpotential for hydrogen evolution and 8 mV for hydrazine oxidation at 10 mA cm⁻², far outperforming conventional electrocatalysts. This low energy requirement is crucial because hydrogen is expected to play a central role in future carbon-neutral energy systems, but conventional water electrolysis has been hindered by the slow and energy-intensive oxygen evolution reaction.
When integrated into a hydrazine-splitting electrolyzer, a Ru@C-200‖Ru@C-200 pair required only 0.11 V to achieve 10 mA cm⁻² and maintained stability for over 100 hours. The researchers further demonstrated a rechargeable zinc-hydrazine battery capable of powering hydrogen production independently, achieving 90% energy efficiency and remaining stable across 600 charge-discharge cycles. This integration creates a self-powered system where hydrogen production, waste treatment, and energy storage occur simultaneously.
The catalyst's ability to completely oxidize hydrazine while generating hydrogen positions it as a practical solution for industries that manage hydrazine-rich wastewater. Hydrazine is an industrial pollutant that can be converted into harmless nitrogen through proper treatment. The research, available at https://doi.org/10.1016/j.esci.2025.100408, shows how engineered Ru-C interfaces simultaneously improve activity, selectivity, and durability for both anodic and cathodic reactions.
Comprehensive characterization using Transmission Electron Microscopy, X-ray Diffraction, Raman Spectroscopy, X-ray Photoelectron Spectroscopy, and Extended X-ray Absorption Fine Structure confirmed the fcc-structured metallic Ru core and enhanced ordering of the carbon shell. In situ analyses revealed that metallic Ru sites are responsible for hydrogen evolution, while surface-generated RuOOH species drive hydrazine oxidation.
This multifunctional approach demonstrates how a single catalyst can address the dual needs of lowering hydrogen production costs and eliminating hazardous pollutants. The strong electronic coupling between the ruthenium core and carbon shell plays a pivotal role in accelerating charge transfer and efficiently activating hydrazine and hydrogen-related intermediates. This innovation may accelerate the adoption of safer, more efficient hydrogen infrastructures and inspire new hydrazine-assisted technologies tailored for clean energy conversion and environmental remediation.
