Electrocatalytic Hydrogen Evolution Performance of Two-dimensional Mo ₂ CT _x MXene Materials: A Review from Preparation to Application

MXenes, an emerging family of two-dimensional (2D) materials with high electronic conductivity, large specific surface area, good hydrophilicity, and regulable surface functional groups, have shown broad application prospects across the domains of energy, catalysis, corrosion prevention, and electromagnetic shielding.Among numerous MXenes, Mo 2 CT x MXene has attracted much attention due to its excellent electrocatalytic hydrogen evolution activity.This paper aims to systematically review the preparation of Mo 2 CT x MXene and its current research status in the field of electrocatalytic hydrogen evolution, providing a comprehensive and clear reference framework for further in-depth study of this system.The synthesis methodologies and exfoliation techniques of Mo 2 CT x MXene in recent years are comprehensively reviewed; the research progress of Mo 2 CT x MXene as an electrocatalyst for hydrogen evolution reaction (HER) is summarized; the optimization strategies for the catalytic performance improvement of Mo 2 CT x MXene for HER are deeply explored from the perspectives of terminated group modification, elemental doping, and hybridization.Finally, a prospective outlook regarding Mo 2 CT x MXene-based composites in the realm of electrocatalytic hydrogen evolution is presented.Despite of significant research advancements on Mo 2 CT x MXene, the absence of eco-friendly and scalablepreparation methodologies remains a critical challenge, contributing to elevated production costs.Additionally, the delayed progress in catalytic mechanism investigations hinders the formulation of rational design strategies.Henceforth, efforts should focus on developing green, fluorine-free synthesis approaches to facilitate large-scale material production, concurrently enhancing catalytic activity and catalyst stability, and accelerating the exploration of catalytic mechanisms.These endeavors are critical to advancing the practical application of Mo 2 CT x and its composite materials in the field of electrocatalytic hydrogen evolution.