Laser-Structured Nickel Electrodes for Enhanced Hydrogen Evolution Kinetics in Alkaline Media at Elevated Temperature

Tailoring the surface morphology of electrocatalysts is one potential opportunity for improving the hydrogen evolution reaction (HER) in alkaline media. Direct laser interference patterning (DLIP) emerged as a promising surface engineering technique for enhancing the HER performance of nickel electrocatalysts in alkaline media. In this study, DLIP is employed to fabricate periodic line-like microstructures on Ni electrodes using a picosecond-pulsed laser system (λ = 1064 nm, τ = 70 ps). By varying cumulated laser fluence up to 2.4 kJ cm^-2, a maximum structure depth of 2.35 ± 0.04 μm and interfacial area ratio up to 87% is reached. HER is evaluated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) at 22 and 60 °C. The DLIP-structured electrodes exhibit significantly enhanced HER activity compared with untreated Ni, showing overpotential reductions of up to 28% at 22 °C and 53% at 60 °C, in conjunction with an increase in electrochemically active surface area (ECSA) from 2.24 to 31.04 cm² at 22 °C and from 1.95 to 74.84 cm² at 60 °C, respectively. These findings highlight the favorable interplay between DLIP-induced surface modification and thermally enhanced HER kinetics.