Arrays of Microscale Linear Ridges with Self-Cleaning Functionality for the Oxygen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Gas bubble accumulation on electrodes hinders electrocatalytic water splitting efficiency by blocking active sites.
• Effective gas management is crucial for optimizing clean hydrogen production and electrocatalytic reaction rates.

Purpose of the Study:

• To investigate the impact of microscale linear ridge electrode morphologies on gas bubble dynamics and oxygen evolution reaction (OER) performance.
• To correlate electrode surface features with improved mass transfer and reduced bubble residence times for enhanced electrocatalysis.

Main Methods:

• Fabrication of nickel electrodes with regular arrays of linear ridges at varying microscale separations.
• High-speed imaging to monitor gas bubble evolution, adhesion, and detachment dynamics on the ridge structures.
• Electrochemical characterization to evaluate OER performance, including current density and sustained operation.

Main Results:

• Linear ridges promoted a 'self-cleaning' effect, inducing simultaneous bubble release and enhancing mass transfer.
• Ridge morphology provided preferential nucleation sites, leading to expedited bubble detachment and shorter residence times.
• Electrodes with 200 μm ridge separation achieved nearly a twofold increase in current density for OER compared to planar electrodes.

Conclusions:

• Engineered linear ridge surface morphologies significantly enhance OER performance by facilitating efficient gas management.
• Self-cleaning electrode designs offer a promising strategy for improving the efficiency of various electrocatalytic gas-evolving reactions.
• Optimized ridge spacing (200 μm) demonstrated superior current densities, highlighting the importance of precise morphological control.