Deciphering pH Mismatching at the Electrified Electrode-Electrolyte Interface towards Understanding Intrinsic Water...

Area of Science:

• Electrochemistry
• Materials Science
• Surface Chemistry

Background:

• Understanding electrode/electrolyte interface control is crucial for advancing electrocatalyst design.
• Microscopic electrode kinetics are essential for developing electrocatalysts with specific functionalities.
• The oxygen evolution reaction (OER) is a critical process in many electrochemical applications.

Purpose of the Study:

• To investigate the key influencing factors controlling the electrode/electrolyte interface.
• To understand the role of local pH effects on the oxygen evolution reaction (OER) using an iridium dioxide electrocatalyst.
• To establish guiding principles for designing high-performance electrocatalysts.

Main Methods:

• Utilized an iridium dioxide electrocatalyst to study the oxygen evolution reaction (OER).
• Investigated the effect of pH mismatch between the local electrode surface and bulk electrolyte.
• Employed a wide spectrum of analytical approaches to verify findings.

Main Results:

• Discovered a significant pH mismatching effect at the electrode/electrolyte interface.
• Demonstrated that intrinsic OER activity is identical under acidic or near-neutral conditions when pH mismatch is adjusted.
• Identified local pH effects at the electrified solid-liquid interface as the primary cause of 'fake' OER performance.

Conclusions:

• Local pH significantly influences observed OER performance, masking intrinsic electrocatalytic activity.
• Adjusting for local pH effects reveals identical intrinsic OER activity for iridium dioxide.
• This work advances the understanding of proton-induced effects at electrode interfaces, aiding future electrocatalyst development.