Advances in etching approaches for synthesis of MAX derived V2CTx MXene and application of V2CTx for green hydrogen production

Among two-dimensional (2D) materials, transition metal carbides and nitrides (MXenes) are a prominent family because of their remarkable dispersion in different solvents, flexible surface chemistry, functional transition metal surfaces, higher mechanical strength, and excellent electric conductivities. However, prominent research has been carried out on titanium-based MXene, especially for green H2 production through photocatalysis and electrochemical approaches, marginalizing the perspective of other MXene sub-families like V2CTx. Therefore, this review broadly summarizes the synthesis approach of V2CTx from V2AlC MAX parent material, mainly involving widely used, simple, and facile HF acid and HCl/fluoride salt for in-situ HF generation etching approaches to obtain highly pure V2CTx. The most significant properties of V2CTx, including electrical, mechanical, and magnetic properties, are discussed, followed by a discussion on the thermal and aqueous solution stability challenges of V2CTx. Moreover, the current catalytic material development in terms of green H2 generation from V2CTx-based nanocomposites is discussed for electrochemical and photocatalytic H2 production applications. Lastly, a detailed conclusion and insight into future perspectives are provided. There is a lack of significant and detailed critical review on the etching approach for the synthesis of pure V2CTx and the application of V2CTxbased nanocomposites for energy-related applications; thus, this review will aid in the advancement of the utilization of MXenes, especially V2CTx for energy-related applications.