Inducing Selenium Vacancy in Nickel Selenide/Iron Selenide by Hydrazine‐Ultrasonic Treatment for Electrocatalytic Water Splitting Reaction

Electrocatalyst plays an important role in enhancing the activity of water‐splitting reaction. Researchers are adopting various techniques like composite formation, doping, and creating vacancy, to improve the catalytic activity of the electrocatalyst. Herein, nickel selenide/iron selenide (NiSe 2 /FeSe 2 ) electrocatalyst is synthesized for electrocatalytic water splitting application, i.e., for oxygen evolution reaction (OER) in 1.0 M KOH electrolytic solution. Further, the activity of the electrocatalyst is enhanced by creating selenium vacancies following a facile reduction method using hydrazine hydrate and simultaneously using ultrasonic power to form the catalyst, namely, V se ‐NiSe 2 /FeSe 2 . Vacancy engineering enhances the electrocatalytic activity of NiSe 2 /FeSe 2 by increasing the electrochemical surface area and number of active sites. Pseudospherical V se ‐NiSe 2 /FeSe 2 vacant sites offer insight into the efficient charge transfer and surface kinetics for the OER.