Disentangling the Pitfalls of Rotating Disk Electrode-Based OER Stability Assessment: Bubble Blockage or Substrate...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Oxygen evolution reaction (OER) catalyst stability is crucial for energy technologies.
• Aqueous model systems (AMSs) like rotating disk electrode (RDE) tests are widely used but may overestimate catalyst stability compared to membrane electrode assembly (MEA) settings.
• Existing research identifies catalyst-backing electrode inertness and bubble shielding as key issues, but their combined impact remains unclear.

Purpose of the Study:

• To investigate the interplay between catalyst-backing electrode material corrosion and bubble shielding in RDE-based OER stability studies.
• To determine the primary cause of the discrepancy between RDE and MEA stability data for OER catalysts.
• To develop methods to improve the reliability of RDE for OER catalyst stability assessment.

Main Methods:

• An inverted RDE setup was utilized.
• Online gas chromatography was employed for quantifying evolved oxygen.
• The experimental design excluded the influence of bubble retention on the catalyst surface.

Main Results:

• The stability discrepancy between RDE and MEA data is primarily caused by corrosion-prone substrate materials in AMS, not by bubble accumulation.
• Mechanistic insights into the degradation process during RDE stability studies were obtained.
• Experimental strategies to mitigate RDE-related limitations were proposed.

Conclusions:

• Corrosion of catalyst-backing electrode materials is the main factor overestimating OER catalyst stability in RDE tests.
• The developed approach allows for accurate dissection of degradation processes in RDE studies.
• Findings facilitate better transferability of stability data between AMS and MEA, advancing OER catalyst development.