Fe,Ce Co‐Doped Ni3S2/NiS Polymorphism Nanosheets With Improved Electrocatalytic Activity and Stability for Water Oxidation

Abstract Balancing the relationship between electrocatalytic activity and stability of sulfide catalysts during oxygen evolution reaction (OER) has been attracting extensive research interest. Here, a simple electrodeposition‐vulcanization two‐step route was designed to successfully construct nickel foam supported sheet‐like Fe,Ce‐codoped Ni 3 S 2 /NiS polymorphism catalyst (labeled as Fe,Ce‐Ni 3 S 2 /NiS/NF). Electrochemical measurements showed that the as‐obtained Fe,Ce‐Ni 3 S 2 /NiS/NF electrode presented excellent OER electrocatalytic performances. In 1 M KOH solution, merely 173 and 234 mV of overpotentials were required to deliver the current densities of 10 and 100 mA cm −2 , respectively. Further investigations revealed that the Fe,Ce co‐doping regulated the electron density around Ni, which promoted the conversion of Ni towards the higher valence state and simultaneously, avoided the stability decrease of the catalyst caused by excessive oxidation corrosion. Moreover, the defects generated during vulcanization also contributed to promoting water oxidation. The present work provides a facile and feasible approach to balance the relationship between the stability and the activity of sulfide catalysts for OER.