Tailoring MXene Surface Chemistry: Strategies, Mechanisms, and Functional Applications

MXenes, a burgeoning family of two-dimensional transition metal carbides, nitrides, and carbonitrides, have garnered significant attention due to their metallic conductivity, hydrophilicity, and surface-rich chemistry, offering immense potential across electrochemical energy storage, catalysis, and advanced sensing. Achieving precise control over their surface chemistry is pivotal for tailoring physicochemical properties and unlocking application-specific functionalities. This review comprehensively summarizes recent progress in MXene chemistry modulation via advanced synthesis protocols and post-synthetic modifications, with an emphasis on surface terminations and interlayer engineering. We discuss the influence of etching conditions, delamination strategies, and intercalation chemistries on the structural and electronic characteristics of MXenes. Moreover, mechanistic insights into ion intercalation and surface functional group evolution are critically analyzed to guide rational design strategies. Key challenges-including batch-to-batch variability, limited scalability, and insufficient mechanistic understanding of surface transformations-are also addressed. This review provides a forward-looking perspective on engineering MXenes with tunable interfaces for next-generation applications in energy, catalysis, and flexible electronic skin systems.