Boosting Acidic Oxygen Evolution Electrocatalysis by Engineering the Interfacial Water at the Electrified...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Optimizing catalyst-electrolyte interfaces is key for efficient electrochemical reactions, particularly proton transfer kinetics.
• Acidic oxygen evolution reaction (OER) stability is often limited by catalyst degradation.

Purpose of the Study:

• To enhance the long-term stability of acidic OER using ruthenium dioxide (RuO2) catalysts.
• To investigate the effect of interstitial boron (B) insertion on RuO2's interfacial water structure and OER performance.

Main Methods:

• Synthesis of boron-inserted ruthenium dioxide (B-RuO2).
• In situ attenuated total reflectance-surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS).
• Local pH monitoring and ab initio molecular dynamics (AIMD) simulations.

Main Results:

• Boron insertion facilitates proton diffusion by enhancing hydrogen-bond network connectivity, suppressing Ru oxidative collapse.
• Interfacial water reorientation and movement of nonbonding oxygen away from the Fermi level reduce structural corrosion.
• B-RuO2 demonstrates over 1000 hours of stable OER operation at 10 mA cm-2 and high performance in a proton exchange membrane water electrolyzer (PEMWE).

Conclusions:

• Engineering interfacial water structure via interstitial boron insertion is a novel strategy to promote acidic OER stability.
• This approach significantly improves proton diffusion kinetics and prevents catalyst degradation, paving the way for more robust electrolyzer designs.