Electrodeposited laser – nanostructured electrodes for increased hydrogen productionElectrodeposited laser – nanostructured electrodes for increased hydrogen production Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2024-01-052022enIn the present work, a novel approach has been employed to effectively enlarge the electrocatalytic 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 electrochemical values (ii) a significant increase of double-layer capacitance (CDL) (values up to 1945 μF cm−2) compared to that of an LN electrode (288 μF cm−2) (iii) higher Jpeaks 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 |η|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).PL, MF, AK, NP acknowledge financial support from the European Union’s Horizon 2020 research and innovation program under grant agreement no 871124 Laserlab-Europe. The authors would like to acknowledge the HELLAS-CH national infrastructure (MIS 5002735) implemented under “Action for Strengthening Research and Innovation Infrastructures,” funded by the “Operational Programme Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020) and co-financed by Greece and the European Union (European Regional Development Fund).http://creativecommons.org/licenses/by/4.0/International Journal of Hydrogen Energy47169527-9536 Poimenidis Ioannis Ποιμενιδης Ιωαννης Papakosta Nikandra Manousaki Alexandra Klini Argyro Farsari Maria Moustaizis Stavros Μουσταιζης Σταυρος Loukakos Panagiotis Elsevier Alkaline electrolysis Electrodeposition on Ni Ultrafast laser nanostructuring Hydrogen production