2D Bifunctional Materials: Unlocking Innovations for Efficient Water Splitting

Abstract

Two-dimensional (2D) bifunctional materials have emerged as a transformative class for water splitting due to their exceptional physicochemical properties, high surface area, and tunable electronic characteristics. This review focused to explore the recent progress, of 2D materials to show bifunctional activity, different strategies followed for modifying their surface and interface properties that is ultimately helps in expanding overall water splitting including both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) elevating the path for fuel-cell industries and electrolyzers. Key 2D materials including graphene-derived materials, transition metal di-chalcogenides (TMDs), porous organic polymers (POPs), Layered Double Hydroxides (LDH), MXenes, and nanosheets, are discussed with a focus on their structural modifications, surface functionalization, and hybridization strategies to enhance bifunctionality. Their unique attributes, such as Fermi-level tunability, electronic and optical properties, and mechanical robustness, are analyzed to understand their catalytic performance. Applications in overall water splitting and potential parameters along with the mechanism for HER and OER are discussed. Finally, this review identifies existing challenges, such as commercialization, scalability, stability, and cost-efficiency. It provides insights into future advances needed to enable the widespread adoption of these materials in real-world applications.