N/S‐Codoped Nickel Oxide Supported on Activated Montmorillonite Clay as an Efficient Bifunctional Electrocatalyst for Overall Water Splitting

Abstract Developing low‐cost, highly effective, and durable electrocatalysts for overall water splitting (OER/HER) is crucial for future energy provision. Herein, we report N/S‐codoped Nickel oxide supported on activated Montmorillonite clay as an efficient bifunctional electrocatalyst for water electrolysis. The different wt % of Ni‐MMT catalysts were synthesized using an effortless one‐step solvothermal method and their phase recognition, morphology, analysis of elements, and electrochemical performance were confirmed by various characterization techniques. The optimal 10 Ni‐MMT catalyst exhibits outstanding efficiency in both HER (170 mV) and OER (365 mV) at a current density of 10 mA cm −2 in 1 M KOH. Furthermore, doping of N/S heteroatoms increases the active sites for HER/OER, facilitates charge transfer and achieves electrochemical stability of 15 h. The Ni‐MMT catalyst achieved an overall water‐splitting performance in 1 M KOH, reaching 10 mA cm −2 at a cell voltage of 1.82 V.