Electrodeposited laser-nanostructured electrodes for increased hydrogen production

In the present work, a novel approach has been employed to effectively enlarge the elec-trocatalytic area of the electrodes in an alkaline electrolysis setup. This approach consists of a two-step electrode fabrication process: In the first step, ultrashort laser pulses have been used to nanostructure the electrode surface. In the second step, electrodeposition of nickel particles was performed in a modified Watt's bath. The resulting electrodes have been found to exhibit a significantly increased hydrogen evolution reaction (HER) activity. Compared to the laser-nanostructured electrode (LN) and an untreated (i.e., flat) electrode, the electrodeposited-laser-nanostructured (ELN) electrode provides (i) enhanced electro-chemical values (ii) a significant increase of double-layer capacitance (C-DL) (values up to 1945 mF cm(-2)) compared to that of an LN electrode (288 mF cm(-2)) (iii) higher J(peaks) at CVs sweeps and (iv) lower Tafel slopes (-121 mV dec(-1) compared to-157 mv dec(-1)). The ELN electrode provides an overpotential value of vertical bar eta vertical bar(100) = 264 mV, which shows a noteworthy 34% decrease compared to a flat Ni electrode and a 15% decrease to an (LN) electrode. Scanning electron microscopy (SEM) revealed that the electrodeposition of nickel on the LN nickel electrodes results in a dendrite-like morphology of the surface. Thus, the enhancement of the HER has been attributed to the dendrite-like geometry and the concomitant enlargement of the electrocatalytic area of the electrode, which presents an electrochemical active surface area (ECSA) = 97 cm(-2) compared to 2.8 cm(-2) of the flat electrode. The electrodes have also been tested in actual hydrogen production condition, and it was found that the ELN electrode produces 4.5 times more hydrogen gas than a flat Ni electrode and 20% more hydrogen gas than an LN electrode (i.e. without the extra nickel electrodeposition). (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A novel approach of nanostructuring the electrode surface and electrodeposition of nickel particles has been employed to enlarge the electrocatalytic area of electrodes in an alkaline electrolysis setup. The resulting electrodes exhibit significantly increased hydrogen evolution reaction (HER) activity and produce more hydrogen gas under actual hydrogen production conditions.