Engineering space dimensional and surface chemistry of MXene-based nanocomposite photocatalysts for sustainable environmental application

It is very urgent to solve environmental pollution problem. MXene-based composite photocatalysts show great promise, which utilize solar energy for purification. MXenes have excellent electrical conductivity, a large surface area due to their 2D structure, and surface functional groups beneficial for photocatalysis. In this review, various synthesis methods have been developed to prepare MXenes with different properties for specific applications, such as hydrofluoric acid etching, substitutes etching and molten fluoride etching. The influence of different groups on the performance of MXene have been determined. In photocatalytic reactions, modification strategies including heterojunction construction, doping, precious metal deposition and single atom anchor have been explored to enhance the photocatalytic performance of MXene-based composites. It is found that MXenes can act as support that limits photocatalyst size, enhance reactant adsorption, and functions as cocatalyst loaded onto semiconductors to improve charge separation. Our perspectives on the key challenges and future directions of developing high-performance MXene-based composite photocatalysts for environmental application are elaborated.