Synergistically coupling of trimetallic sulfides on Ni foam as porous self-supported electrodes for alkaline water splitting

The development of highly active, highly durable, and inexpensive electrode materials for water electrolysis is essential for future sustainable energy systems. Herein, we demonstrate heterostructures of metal sulfides deposited on Ni foam (NF) through electrodeposition for highly efficient water splitting. Iron-cobalt-nickel sulfides deposited on Ni foam (FeCoNiS@NF) exhibit a low overpotential of 302 mV (at 50 mA cm−2) for OER, and molybdenum-cobalt-nickel sulfides on Ni foam (MoCoNiS@NF) can provide a current density of 10 mA cm−2 at an overpotential of 114 mV for HER in alkaline solution. The lower charge-transfer resistance and Tafel slope values for FeCoNiS@NF and MoCoNiS@NF electrodes demonstrate the favorable reaction kinetics toward OER and HER, respectively, resulting from their intrinsic catalytic activity, good electrical conductivity, and accessible active sites. Furthermore, FeCoNiS@NF as anode and MoCoNiS@NF as cathode require a cell voltage of 1.68 V to produce a current density of 10 mA cm−2 with impressive durability under alkaline conditions, further proving the advancement and potential of trimetallic sulfides with optimal interfaces in the development of cost-effective electrodes for alkaline water splitting.