Emerging Platforms for High-Efficiency Solar-Driven Interfacial Evaporation Desalination: MXene-Based Hydrogels/Aerogels

The sustainable supply of freshwater resources is facing serious challenges due to the rapid industrial development, massive expansion of urbanization, and increasing environmental pollution. Solar-driven interfacial evaporation desalination (SIED) is considered one of the most promising candidates to tackle water scarcity and energy crisis, owing to its sustainable solar energy, abundant water sources, and pollution-free characteristic. MXene has attracted considerable attention in the domain of purified water production, owing to its remarkable properties, including tunable hydrophilicity, ease of processing, resistance to fouling, mechanical strength, and photothermal conversion capabilities. This review provides a comprehensive overview of the research progress of hydrogels/aerogels in the SIED field. Firstly, the synthesis strategy and the significantly distinctive features of MXene and its nanocomposites are outlined. Secondly, based on the photothermal conversion capacity and ease of modulation of MXene, various fabrication processes of MXene aerogels are analyzed, and the varying wettability levels of the MXene aerogel-based evaporators are discussed and summarized. Thirdly, the properties of MXene hydrogel-based evaporators are discussed from four perspectives: photothermal conversion capacity, water transport capacity, evaporation enthalpy regulation, and salt resistance. Finally, the challenges and issues related to the development of MXene hydrogels/aerogels in SIED are further discussed.