Borophene-based electrocatalysts: an account of the fabrication approach, structural properties and electrochemical applications.

Borophene, a two-dimensional allotrope of boron positioned between metals and non-metals in the periodic table, has emerged as a promising material due to its electron-deficient bonding and unique structural characteristics. Although borophene shares certain similarities with graphene, its distinct atomic arrangements result in enhanced flexibility, intrinsic anisotropy, and a rippled morphology, which significantly influence its physicochemical properties. In recent years, borophene has attracted considerable attention owing to its high tensile strength, excellent electrical and thermal conductivity, and versatile mechanical and optical properties, making it a strong candidate for advanced technological applications. This review systematically examines the growing importance of 2D materials, with particular emphasis on borophene. It provides a comprehensive overview of synthesis strategies, including bottom-up and top-down approaches, along with detailed discussion of structural features, physicochemical properties, and characterization techniques. Furthermore, the electrocatalytic applications of borophene in energy conversion reactions, such as the hydrogen evolution reaction, oxygen evolution reaction, carbon dioxide reduction, and nitrogen reduction reaction, are discussed with emphasis on the underlying structure-property relationships. In addition, its role in electrochemical sensing is highlighted in terms of sensitivity, selectivity, and charge-transfer behavior. Also, comparison with other 2D materials has been introduced. Finally, the current challenges, including stability and scalability issues, are critically addressed, and future research directions are proposed to guide the development of borophene-based materials for next-generation energy and sensing applications.