A Superaerophobic 3D Array Electrode Promotes Gas Bubble Management in Alkaline Water Splitting

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Efficient gas bubble management is crucial for alkaline water electrolysis efficiency.
• Adherent bubbles in electrolysis lead to high overpotentials and unstable current densities.
• Optimizing electrode structure aids bubble detachment but ordered structures with clear performance relationships are challenging.

Purpose of the Study:

• To develop a superaerophobic ordered 3D honeycomb Ni micromesh (3D HNM) integrated with NiCoP catalysts (3D HNM@NCP).
• To minimize bubble adhesion and enhance bubble detachment for improved alkaline water electrolysis.
• To establish a clear structure-performance relationship in advanced electrode design.

Main Methods:

• Photolithography and electrodeposition to create a hierarchical electrode structure.
• Fabrication of a superaerophobic surface with a discontinuous triple-phase contact line.
• Operando high-speed imaging and finite element simulations to analyze bubble dynamics.

Main Results:

• The 3D HNM@NCP electrode reduced bubble detachment size to ~100 μm, accelerating bubble release.
• Achieved a low overpotential of 134 mV for the hydrogen evolution reaction.
• Demonstrated outstanding durability (>60 h at 100 mA cm⁻²) and stable overall water electrolysis (>24 h at 400 mA cm⁻²).

Conclusions:

• The superaerophobic 3D ordered structure effectively promotes gas bubble removal in alkaline water electrolysis.
• The developed 3D HNM@NCP electrode offers a promising solution for efficient and durable hydrogen production.
• This work presents an effective strategy for designing advanced electrodes by controlling surface properties and structure.