Lignin-Directed Construction of Vertical Ru/RuO₂ Electron-Bridge Interfaces for Low-Input Self-Powered...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Hydrazine oxidation reaction (HzOR) is a promising alternative to oxygen evolution reaction (OER) for hydrogen production.
• Current two-electrode electrolyzers require high voltages and external power, limiting scalability.

Purpose of the Study:

• To develop a highly efficient and stable electrocatalyst for hydrogen production using hydrazine oxidation.
• To investigate the catalytic mechanism at the interface of the novel catalyst.

Main Methods:

• Hydrothermal activation of lignin to chelate Ru³⁺, forming Ru/RuO₂ heterojunctions.
• Pyrolysis of the chelated complex within a hierarchical lignin-derived carbon (HLC) matrix.
• Spectroscopic analysis and Density Functional Theory (DFT) calculations to understand the dynamic dual-center (DDC) mechanism.
• Electrochemical testing in 1.0 M KOH electrolyte.

Main Results:

• The Ru/RuO₂@HLC catalyst demonstrated efficient hydrogen evolution reaction (HER) activity, achieving 50 mA cm⁻² at a low overpotential of 12 mV, surpassing commercial Pt/C.
• Replacing OER with HzOR reduced the cell voltage to 0.14 V at 100 mA cm⁻².
• The DDC mechanism at the catalyst interface was identified, enhancing charge transfer and suppressing catalyst dissolution.
• A direct hydrazine fuel cell and hydrazine splitting system achieved a high hydrogen production rate of 2.32 mmol h⁻¹ with 100% Faradaic efficiency.

Conclusions:

• The Ru/RuO₂@HLC catalyst, derived from renewable biomass, offers a scalable and efficient platform for hydrogen production via hydrazine splitting.
• The study highlights the potential of biomass-derived ligands for designing advanced interfacial electrocatalysts.
• This approach provides a sustainable pathway for waste-to-hydrogen conversion.