Porous Heterogeneous Sulfide Nickel/Nickel Iron Alloy Catalysts for Oxygen Evolution Reaction of Alkaline Water Electrolysis at High Current Density

Alkaline water electrolysis is the important pathway for the green hydrogen production, where oxygen evolution reaction (OER) is the rate-limiting step due to the sluggish reaction kinetics. Transition metal heterogeneous catalyst is the kind of important OER catalyst for alkaline water electrolysis due to its good performance, low price and environmental friendliness. In this work, the porous sulfide nickel@nickel iron alloy catalyst (i.e. NM/NS@Ni3Fe) is prepared by the designed high-temperature vulcanization and multi-step electrodeposition method. The NM/NS@Ni3Fe catalyst exhibits an outstanding OER performance in an alkaline environment, with a low potential of 1.53 V at high current density of 1000 mA cm−2 and a low Tafel slope of 89 mV dec−1. The excellent OER performance is attributed to the unique electronic structure of Ni3S2/Ni3Fe heterogeneous interface and the catalyst layer with porous structure. The results indicate that Ni3S2 provides good electronic conductivity and the low electronegativity S atoms increase the formation of oxygen vacancies, which effectively improves the OER performance. In addition, the hydrophilic and porous structure of the electrode facilitates bubbles release and electrolyte flow at high current density. It provides the guidance for the design of porous heterogeneous OER catalysts with good-performance.