Hegazy, Mohamed Barakat ZakariaMohamed Barakat ZakariaHegazyZander, JudithJudithZanderWeiss, MortenMortenWeissSimon, ChristopherChristopherSimonGerschel, PhilippPhilippGerschelSanden, Sebastian A.Sebastian A.SandenSmialkowski, MathiasMathiasSmialkowskiTetzlaff, DavidDavidTetzlaffKull, TobiasTobiasKullMarschall, RolandRolandMarschallApfel, Ulf-PeterUlf-PeterApfel2024-04-222024-04-222024https://publica.fraunhofer.de/handle/publica/46671710.1002/smll.202311627For a carbon-neutral society, the production of hydrogen as a clean fuel through water electrolysis is currently of great interest. Since water electrolysis is a laborious energetic reaction, it requires high energy to maintain efficient and sustainable production of hydrogen. Catalytic electrodes can reduce the required energy and minimize production costs. In this context, herein, a bifunctional electrocatalyst made from iron nickel sulfide (FeNi2S4 [FNS]) for the overall electrochemical water splitting is introduced. Compared to Fe2NiO4 (FNO), FNS shows a significantly improved performance toward both OER and HER in alkaline electrolytes. At the same time, the FNS electrode exhibits high activity toward the overall electrochemical water splitting, achieving a current density of 10 mA cm-2 at 1.63 V, which is favourable compared to previously published nonprecious electrocatalysts for overall water splitting. The long-term chronopotentiometry test reveals an activation followed by a subsequent stable overall cell potential at around 2.12 V for 20 h at 100 mA cm-2.enelectrochemical behaviorspinel bimetallic sulfidesstabilitysurfacewaterElektrolysejournal article