Refractory Metal-Based MXenes: Cutting-Edge Preparation and Applications.

Refractory metal-based MXenes refer to MXenes with M as a refractory metal. Due to their high conductivity, large specific surface area, multiple active sites, high photothermal conversion efficiency, adjustable surface groups, and controllable nanolayer spacing, they hold broad application prospects in various fields such as photoelectrocatalysis, biomedicine, water treatment, electromagnetic shielding, and sensors. The unique physical properties of refractory metal-based MXenes are related to their electronic and crystal structures. The interstitial layer causes the carbides to exhibit different behavior compared to the original metal. At the same time, different preparation methods have a great influence on the interlayer spacing and surface termination of refractory metal-based MXenes, thus affecting their performance. This review systematically summarizes the latest progress in the preparation methods and frontier applications of refractory metal-based MXenes, offering new insights for further development. Additionally, various characterization techniques and first-principles calculations are summarized, which are crucial for optimizing refractory metal-based MXenes for applications such as catalysis, energy storage, and sensors. In summary, the current challenges and future development prospects of refractory metal-based Mxenes are addressed, aiming to provide indispensable information for the intelligent design of 2D materials in the future.