Direct Laser Interference Patterning of Nickel Electrodes: Enhanced Hydrogen Evolution and Bubble Dynamics through Surface Engineering

Direct laser interference patterning (DLIP) with nanosecond laser pulses at 355 nm was employed to microstructure nickel Watts (Ni-Watts) electrodes with a periodic channel-like structure, aiming to enhance their performance toward the hydrogen evolution reaction (HER) in alkaline media. This technique enables the treatment of large surface areas with high reproducibility without significantly altering the chemical composition of the material. Electrochemical characterization at 30 °C in 2 M KOH revealed that the introduction of microchannels increases the catalytic activity for HER by increasing the current density up to 23% at −1.5 V versus SCE without affecting the kinetic and thermodynamic properties of the material. Although electrochemical impedance spectroscopy indicated no significant changes in the active surface area (roughness factor close to 1), this improvement is attributed to favorable modifications in bubble dynamics; Ni-Watts electrodes displayed multiple nucleation zones and smaller maximum bubble diameters, while Ni electrodes with 5 μm microchannels exhibited fewer nucleation sites and larger bubbles. These results demonstrate that DLIP structuring offers a promising strategy to optimize HER efficiency without requiring changes in material composition.