Atomically engineered interfaces inducing bridging oxygen-mediated deprotonation for enhanced oxygen evolution in...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and stable electrocatalysts are essential for commercializing proton exchange membrane electrolyzers, particularly for water oxidation in acidic media.
• Existing catalysts often face a trade-off between activity and stability, limiting their practical application.

Purpose of the Study:

• To develop novel electrocatalysts with improved efficiency and stability for the oxygen evolution reaction (OER) in acidic media.
• To investigate the fundamental mechanisms underlying the enhanced catalytic performance of Ru-O-Ir interfaces.

Main Methods:

• Synthesis of Ru-O-Ir atomic interfaces.
• Electrochemical characterization, including overpotential measurements at various current densities and long-term stability tests (>1000 h).
• Operando spectroelectrochemical measurements and theoretical calculations to elucidate reaction mechanisms.

Main Results:

• The Ru-O-Ir catalysts achieved low overpotentials (167 mV at 10 mA cm⁻²) in 0.5 M H₂SO₄.
• Exceptional stability was demonstrated, with sustained operation for over 1000 hours at 10 mA cm⁻² and negligible degradation after 200,000 CV cycles.
• Mechanistic studies revealed a near-optimal OER pathway involving a bridging oxygen site on Ir (Ir-O_BRI) acting as a proton acceptor, accelerating proton transfer at an adjacent Ru site and overcoming typical scaling limitations.

Conclusions:

• Rational design of multiple active sites, such as Ru-O-Ir interfaces, can effectively break the activity/stability trade-off in OER catalysts.
• The identified mechanism offers a promising strategy for developing high-performance electrocatalysts for acidic oxygen evolution reactions.
• This work provides valuable insights for advancing proton exchange membrane electrolyzer technology.