Visualizing and quantifying local OER activity on stainless-steel mesh via gas bubble dynamics

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Efficient catalysts for the oxygen evolution reaction (OER) are vital for sustainable energy technologies.
• Stainless steel mesh (SSM) offers a low-cost alternative to precious metal catalysts for OER.
• Understanding the spatial distribution of active sites on SSM is crucial for optimizing its performance.

Purpose of the Study:

• To develop an in situ method for visualizing and quantifying localized OER activity on SSM electrodes.
• To investigate the role of mechanical strain in OER activity on SSM.
• To identify the underlying mechanisms responsible for enhanced OER activity in strained regions.

Main Methods:

• Utilized in situ oxygen bubble evolution dynamics and time-resolved optical tracking to monitor OER activity.
• Employed in situ electrochemical Raman mapping to analyze surface composition and phase transitions.
• Investigated SSM model electrodes under controlled electrochemical conditions.

Main Results:

• Demonstrated that curved, strained regions of SSM exhibit significantly enhanced OER activity.
• Observed accelerated bubble nucleation and growth in compressive strain domains.
• Revealed that compressive strain promotes the phase transition of nickel hydroxide to nickel oxyhydroxide at lower potentials.

Conclusions:

• Gas bubble dynamics serve as a powerful tool for spatially resolved quantification of electrocatalytic activity.
• Compressive strain is a key factor influencing the formation of catalytically active phases on stainless steel.
• This research provides insights for designing high-performance, low-cost OER catalysts based on stainless steel.