Recent developments of MXene-based catalysts for hydrogen production by water splitting

MXenes are a type of two-dimensional graphene-like layered material with a wide variety of species, high earth abundance and low cost. Because of their unique physical, chemical, optical, electronic and mechanical properties, they can realize multi-functional catalysis for hydrogen production by water splitting. However, due to the fact that research on electrocatalysis using MXene-based materials is in its infancy, currently the focus is on basic types of MXene-based materials, such as Ti3C2Tx and Mo2CTx. In this case, the investigation of their specific catalytic mechanism combined with various in situ characterizations and optimization of their catalytic performance under the guidance of DFT theoretical calculations are still inadequate. Furthermore, there are no methods completely suitable for their large-scale industrial production at present, and thus-there is plenty space for the exploration and development of MXene-based materials. Based on these facts, herein, we summarize the main electrocatalytic mechanisms and indices for the evaluation of the HER, OER, and water splitting on MXene-based catalysts in acidic and alkaline media and review the research progress of 2D/3D MXene-based catalysts and their modification and compounding with other materials in the field of water electrolysis in recent years. Finally, combined with theoretical calculations, we predict the challenges that MXene composite materials will face in the future when they are used for efficient hydrogen production from water splitting.