Interstitial-Substitutional-Mixed Solid Solution of RuO₂ Nurturing a New Pathway Beyond the Activity-Stability Linear...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Acidic oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane water electrolyzers (PEMWE) face activity-stability trade-offs.
• Conventional adsorbate evolution mechanism (AEM) leads to overoxidation in highly oxidative environments.

Purpose of the Study:

• To propose a novel proton acceptor-electron donor mechanism (PAEDM) in RuO2.
• To break the activity-stability trade-off in acidic OER using a mixed solid solution structure.

Main Methods:

• Constructed interstitial-substitutional mixed solid solution structure (C,Ta-RuO2).
• Utilized in situ spectroscopy and theoretical calculations.
• Fabricated a homemade PEMWE.

Main Results:

• C,Ta-RuO2 demonstrated a favorable PAEDM, reducing deprotonation energy barrier and enhancing activity.
• Substitutional Ta prevented Ru overoxidation, ensuring long-term stability.
• Optimized C,Ta-RuO2 achieved low overpotential (171 mV) and ultra-long stability (>1300 h).
• A homemade PEMWE with C,Ta-RuO2 showed high water splitting performance (1.63 V@1 A cm-2).

Conclusions:

• The study presents a novel strategy to develop efficient OER electrocatalysts.
• PAEDM in C,Ta-RuO2 effectively addresses the activity-stability challenge in acidic OER.
• This approach guides future developments in water oxidation catalysis for PEMWE.