All-in-one MXene/PDA@MF-EF solar steam generator with semi-clad construction for efficient interfacial evaporation, water purification and desalination

Interfacial solar-driven water evaporation technology is considered a cost-effective strategy to mitigate the shortage of freshwater resources at present. However, the coordinated regulation of thermal and water management remains a significant challenge in the design of evaporation systems. From the practical application viewpoint, it is essential to develop an economical, expandable, and simple preparation process for high photothermal conversion capacity and super hydrophilic evaporators. Here, a novel all-in-one MXene/PDA@MF-EF solar evaporator with a porous semi-cladding structure was designed by embedding EPE foam as a base layer (named MF-EF) inside a melamine foam (MF) and coating MXene/PDA as a light-absorbent layer on the surface of MF-EF (named MXene/PDA@MF-EF). The designed MXene/PDA@MF-EF vaporizer has excellent photothermal conversion capability and water transport channel. The MXene/PDA@MF-EF evaporator exhibits an evaporation rate reaching 1.5576 kg m −2  h −1 and a photothermal conversion efficiency of 92.63 % under 1 kW m −2 irradiation. Meanwhile, it exhibits good long-term stability and salt resistance when continuously treating seawater and different concentrations of NaCl solutions. For practical application, an outdoor evaporation device was designed, and the maximum freshwater production of up to 7.170 kg m −2 was achieved under 9 h of sunlight. Hence, the MXene/PDA@MF-EF evaporator enables clean water production through the coordinated action of thermal and water management, providing a viable and stable alternative to solar water evaporation in a variety of aqueous environments. Further, it provides a solution for realizing solar-driven interfacial evaporation desalination technology for freshwater access in coastal and offshore islands.