Ionic liquid‐assisted synthesis of N, F, and B co‐doped BiOBr/Bi₂Se₃ on Mo₂CT_x for enhanced performance in hydrogen evolution reaction and supercapacitors

Heteroatom doping and heterojunction formation are effective strategies to enhance electrochemical performance. In this study, we present a novel approach that utilizes an ionic liquid-assisted synthesis method to fabricate a BiOBr-based material, which is subsequently loaded onto Mo₂CT_x via a selenization treatment to create a BiOBr/Bi₂Se₃ heterostructure, denoted as NBF-BiOBr/Bi₂Se₃/Mo₂CT_x. The incorporation of heteroatoms improves its hydrophilicity and electronegativity, while the formation of heterojunctions adjusts the electronic structure at the interface, resulting in lower OH^–/H⁺ adsorption energy. The specific surface area of NBF-BiOBr/Bi₂Se₃/Mo₂CT_x is 193.1 m²/g. In hydrogen evolution reaction (HER) tests, NBF-BiOBr/Bi₂Se₃/Mo₂CT_x exhibits exceptional catalytic performance in acidic media, requiring only an overpotential of 109 mV to achieve a current density of 10 mA cm⁻². Furthermore, NBF-BiOBr/Bi₂Se₃/Mo₂CT_x demonstrates superior electrochemical performance in an asymmetric supercapacitor, with an energy density as high as 55.6 Wh kg⁻¹ at a power density of 749.9 Wh kg⁻¹. This work provides a novel approach for heteroatom doping and heterojunction synthesis, offering promising prospects for further advancements in the field.