Biomimetic 3D Membranes with MXene Heterostructures for Superior Solar Steam Generation, Water Treatment, and Electricity Generation

摘要

2D MXene materials have shown great potential in photothermal conversion,especially for solar steam generation. However, the obvious light losses at theliquidsolid interfaces still limit its broad applications, thereby resulting in a poorlight absorption ability. To this end, a facile and general approach is designed forthe construction of nanoflower MXene@MoS_2 with excellent photothermalconversion ability via one-step hydrothermal process. Thanks to the multireflectiveand synergestic effects between Mxene and MoS_2, the hierarchicalMxene@MoS_2 heterostructure exhibits broadband light absorption andimproved photothermal conversion capacity (69 °C after 10 min solar illumination).Furthermore, inspired by the water vapor process in multiple channels oftrees, an ultrathin Mxene@MoS_2-based nanofibrous membrane is assembled viadirectional electrospinning technology. Compared with traditional irregularchannels, the controllable and tree-inspired 3D structure shows competitiveadvantages in solar absorption and water transport. Thus, the as-prepared selffloatingmembrane presents durable hydrophobicity (contact angle [CA] ¼ 125)and a high evaporation rate of 1.39 kg/(m~2h) (91% efficiency) under 1 sun, whichis higher than reported. This 3D Mxene-based device also shows promisingelectrical generation, solar-driven sewage, and desalination treatments (99%desalination efficiency). Such high-performance self-floating photothermalmembranes with multifunctionalities might provide an effective strategy forsolving the global problems of freshwater shortage.