Co-doped RuO₂ nanoparticles with enhanced catalytic activity and stability for the oxygen evolution reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and stable electrocatalysts are vital for hydrogen energy technologies, particularly for the oxygen evolution reaction (OER).
• Rutile RuO2 is a promising OER catalyst but suffers from poor stability due to oxidative dissolution at high potentials.

Purpose of the Study:

• To develop a Co-doped RuO2 nanoparticle catalyst for improved OER activity and stability in alkaline media.
• To investigate the mechanism by which Co doping enhances catalytic performance and durability.

Main Methods:

• Synthesis of Co-doped RuO2 nanoparticles.
• Electrochemical characterization of OER performance, including overpotential measurements at different current densities.
• Durability testing under continuous operation and accelerated cycling conditions.

Main Results:

• Ru0.95Co0.05O2 demonstrated significantly enhanced OER activity, with low overpotentials of 217 mV at 10 mA cm-2 and 290 mV at 100 mA cm-2 in 1 M KOH.
• The catalyst exhibited outstanding stability, maintaining performance for 50 hours at 100 mA cm-2 and showing minimal degradation after 2000 cycles.
• Co doping promotes oxygen vacancies and increases electron density around Ru, enhancing oxygen species adsorption and inhibiting RuO2 dissolution.

Conclusions:

• Co-doped RuO2 nanoparticles represent a highly active and stable electrocatalyst for the oxygen evolution reaction.
• The doping strategy effectively addresses the stability limitations of pure RuO2, paving the way for practical hydrogen energy applications.