FeNi<sub>2</sub>S<sub>4</sub>–A Potent Bifunctional Efficient Electrocatalyst for the Overall Electrochemical Water Splitting in Alkaline Electrolyte
Mohamed B. Zakaria, Judith Zander, Morten Weiß, Christopher Simon, Philipp Gerschel, Sebastian Sanden, Mathias Smialkowski, David Tetzlaff, Tobias Kull, Roland Marschall, Ulf‐Peter Apfel
Abstract
Abstract For 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 (FeNi 2 S 4 [FNS]) for the overall electrochemical water splitting is introduced. Compared to Fe 2 NiO 4 (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 .