MoS2@sponge with double layer structure for high-efficiency solar desalination

A novel three-dimensional (3D) MoS2-based evaporator (MPU-PPU) was constructed for solar desalination in this work. This evaporator provided a typical design of double layer structure (DLS): the top layer which was formed via embedding nanoscale MoS2 onto frameworks of 3D porous polyurethane (PU) sponge, played the role of solar absorbing and photothermal conversion, while the bottom layer which was originated from PU sponge with the hydrophilic PDA coating, functioned as the thermal insulation layer and water pump. With low cost, facile construction pathway and good mechanical flexibility, the MPU-PPU evaporator simultaneously exhibited high evaporation efficiency of 85% under a low illumination of 1.0 kW m−2 and superhigh evaporation efficiencies over 90% under higher solar illumination (1.5–2.5 kW m−2), which outperformed many other reported advanced materials for solar desalination. The four factors: (1) high photothermal efficiency, (2) localized heating effect, (3) hydrophilic bottom layer to leverage capillary forces and promote fluid flow to the hot region, together with (4) the porous structure which enabled efficient water supply and vapor channel, mainly accounted for the high-efficiency solar desalination. Besides, the MPU-PPU evaporator exhibited the outstanding desalination efficiency and excellent recyclability, providing great potential in its commercial use for solar desalination.