Potential of MXene-Based Heterostructures for Energy Conversion and Storage

Transition-metal carbides and nitrides (MXenes) have attracted significant interest owing to their desirable properties, abundance, and high electrocatalytic activity. Tremendous studies have demonstrated the potential of MXenes for energy conversion and storage. However, further development of this potential must address various aspects of MXenes, including finite modification strategies, undefined reaction mechanisms, working life cycle, and additional untapped applications. In this Focus Review, we summarize the most recent progress in applications of MXenes and general guidelines for the rational design of MXene structures. The coupling of mixed-dimensional nanomaterials and the introduction of single atoms are discussed in the production of hydrogen, ammonia, and multi-carbon compounds, as well as energy storage applications. In addition, in situ characterization tools are briefly introduced as a potential means of shedding light on MXenes' chemical activity. Finally, an outlook on future opportunities is provided to stimulate discussion and further research into MXene material synthesis and mechanisms.