Recent advances in Ti₃C₂T _x MXene-based composites for electrocatalytic applications

Electrocatalysis is central to the development of sustainable energy conversion technologies and environmental remediation systems, yet the rational design of high-performance, cost-effective, and durable electrocatalysts remains a fundamental challenge. In recent years, MXenes, a rapidly expanding family of two-dimensional transition-metal carbides, nitrides, and carbonitrides, have emerged as a transformative class of materials owing to their metallic conductivity, tunable surface chemistry, rich termination groups, and structural versatility. These unique attributes endow MXenes with exceptional potential for a wide spectrum of electrocatalytic reactions, including the hydrogen evolution reaction, oxygen evolution reaction, and CO₂ reduction reaction. This review provides a fundamental assessment of Ti₃C₂T _x MXene-based electrocatalysts, encompassing synthesis strategies, surface and termination chemistry, and structure-performance relationships. Particular emphasis is placed on how etching routes, delamination processes, and functional group engineering govern catalytic performances. Recent advances in Ti₃C₂T _x MXene composites, heterostructures, and defect engineering are systematically analyzed to elucidate synergistic effects and catalytic enhancement mechanisms. Furthermore, the challenges hindering practical implementation, such as oxidation instability, restacking, ion transport limitations, and the need for scalable manufacturing, are discussed. By integrating experimental insights with theoretical modeling and emerging data-driven approaches, this review outlines future research directions and design principles aimed at bridging the gap between laboratory-scale performance and industrial deployment. Overall, this work is expected to establish Ti₃C₂T _x MXene-based composites as a versatile and continuously evolving platform for next-generation electrocatalysis, while providing a strategic roadmap for their rational design and development in electrocatalytic applications.