Fe‐Incorporated Ni₃S₄/NiS₂ Nanocomposite as an Efficient Electrocatalyst for Alkaline Water Oxidation

Abstract We report the development of iron‐incorporated nickel sulfide (Fe−Ni₃S₄/NiS₂) nanocomposite through sulfurization of iron incorporated nickel hydroxide precursor by using simple solvothermal method. The formation of Ni₃S₄/NiS₂ mixed‐phase material was confirmed by PXRD analysis and the presence of multiple oxidation states of Ni (II and III) and incorporated Fe (III) was revealed by XPS studies. The electrochemical studies demonstrated that Fe−Ni₃S₄/NiS₂ electrocatalyst has a high catalytic activity towards alkaline OER, as it requires only 280 mV overpotential to achieve the benchmark current density of 10 mA/cm²_geo. The superiority of the catalyst was exhibited by low charge transfer resistance of about 6 Ohms, along with low Tafel slope of 43 mV dec⁻¹. Further, the observed long‐term stability for 72 h and remarkable Faradaic efficiency with 99% indicate good durability and excellent selectivity towards OER, respectively. The superior activity of Fe−Ni₃S₄/NiS₂ is attributed to fast kinetics and low charge transfer resistance of the material facilitating the generation of active catalyst.