Interfacial Hydrogen-Bonding Network and Active-Site Electronic Structure Modulation via Indium Doping in RuO₂ for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane (PEM) water electrolyzers are crucial for hydrogen production via water splitting.
• The stability of iridium-free metal oxides, particularly ruthenium oxides (RuO2), remains a significant challenge.
• Degradation of active sites hinders the efficiency and scalability of PEM water electrolyzers.

Purpose of the Study:

• To enhance the stability and activity of ruthenium oxide catalysts for PEM water electrolysis.
• To investigate the effect of indium (In) doping on RuO2 catalyst performance.
• To elucidate the mechanism by which In doping improves catalyst durability and efficiency.

Main Methods:

• Synthesis of indium-doped ruthenium oxide (In-RuO2) catalysts.
• Electrochemical characterization, including overpotential measurements at 10 mA/cm².
• Long-term stability testing at 100 mA/cm² for 600 hours.
• Surface analysis using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS).

Main Results:

• In-doped RuO2 exhibited a low overpotential of 174 mV at 10 mA/cm².
• The catalyst demonstrated remarkable stability, operating for 600 hours at 100 mA/cm².
• Spectroscopic analyses revealed that In doping promotes surface hydroxylation, lowering the water dissociation barrier.
• Doping increased Ru electron density, preventing the formation of unstable high-valence oxides.

Conclusions:

• Indium doping is an effective strategy to enhance the activity and stability of Ru-based catalysts for water splitting.
• Surface hydroxylation induced by In doping plays a critical role in improving catalyst performance.
• This work provides a foundation for developing low-cost, highly efficient catalysts for hydrogen production.