Femtosecond Direct Laser Interference Patterning of Nickel Electrodes for Improving Electrochemical Properties

The present work utilizes Direct Laser Interference Patterning (DLIP) to impart periodic microstructures onto the surface of nickel foils. A pulsed laser source emitting green radiation (514 nm) with pulse duration between 282 fs and 1 ps is utilized to produce line and cross-like pattern geometries having a spatial period of 3.0 µm and a maximum structure depth of ~ 2.8 µm. Both the pulse duration and number of consecutive scans are varied in order to assess their influence on the structure formation. Afterwards, the treated Ni- electrodes are used for alkaline water electrolysis. The most active electrode exhibits an overpotential of -227 mV at a current density of -0.5 A cm^-2 for the Hydrogen Evolution Reaction (HER). Thus, the technique here proposed permitted a 51 % reduction in the overpotential of the HER compared to the untreated Ni-electrode, opening up possibilities for the development of more efficient electrodes for hydrogen production.