Exploiting synergistic effects of graphitic carbon nitride-supported samarium selenide (Sm₂Se₃/g-C₃N₄) nanocomposite for efficient OER/HER in an alkaline medium

Developing low-cost and efficient electrocatalysts to drive hydrogen and oxygen evolution reactions in electrochemical water splitting is a crucial demand on an industrial scale. In this work, the hydrothermal strategy is adopted to fabricate an electrocatalyst based on Sm₂Se₃ and Sm₂Se₃/g-C₃N₄ on stainless steel (SS) substrate and reported the OER/HER catalytic performance of both catalysts in an alkaline medium. The different characterization techniques confirm excellent physical properties like phase purity, chemical interaction, chemical composition, and porous sheet-like structure of composite material. Interestingly, this interconnected porous network showed excellent conductivity and abundant active sites, improving OER/HER. The composite catalyst required a low overpotential of 218 mV (for OER) and 277 mV (for HER) to obtain a 10 mA cm⁻² current density. The values of Tafel slope and polarization resistance were reduced in the Sm₂Se₃/g-C₃N₄ electrocatalyst. In addition, the chronoamperometry test over 45 h confirmed the excellent stability of the composite. This work demonstrates that the strong coupling of metal chalcogenide with C-support opens a new avenue for designing an efficient electrocatalyst for water-splitting applications.