A thermos-inspired double structural design for efficient and sustainable solar-driven water purification

Solar-driven interfacial water evaporation has great application prospects in sewage purification and seawater desalination due to its environment-friendly and energy-efficient. However, the single-mode solar evaporator and fragile thermal management design may greatly hinder its efficient evaporation and practical application. Herein, a novel thermos-inspired double structural evaporator (DCWF) composed of carbon black, nonwoven and extruded polystyrene was developed by a very simple and green method. The DCWF possesses characteristics with low thermal conductivity, continuous and efficient water transportation, and excellent light absorption (∼100%) within the wavelength range from 250 to 2500 nm, which can effectively promote evaporation efficiency. Consequently, the photothermal conversion efficiency of the DCWF was as high as 92.3% and the evaporation rate was up to 1.38 kg·m−2h−1 under one-sun solar illumination. Additionally, the applicable potential of DCWF has been validated by experimental results in the desalination of seawater, sewage purification, and circulation. The findings of this research not only offered a novel double-layer solar evaporation device with excellent photothermal conversion capability and remarkable stability, but also open a new avenue to optimize the solar interfacial evaporation mode.