Mangrove-inspired double-layer aerogel with excellent salt-resistance for efficient interfacial solar steam...

With the dual advantages of environmental friendliness and high efficiency, interfacial solar steam generation (ISSG) holds significant promise for sustainably alleviating global water shortages. However, how to achieve efficient evaporation and salt resistance simultaneously still face challenge. Herein, inspired by the mangrove, a TPU/PAN/CNTs double-layer (TPCD) evaporator was constructed using a combination of directional freezing and salt templating. The prepared evaporator features vertically ordered channels in the upper layer and a honeycomb-like pore structure in the bottom layer. The upper vertical channels enhance surface light absorption, salt ion diffusion, and water transport rate, while the honeycomb structure facilitates water absorption and minimizes heat loss, and thus enables coordination between thermal management and water transport. The advantages of this structure in evaporation and salt resistance were demonstrated by numerical simulations. The TPCD evaporator with optimized structure achieves an evaporation rate of 2.66 and 2.61 kg m^-2 h^-1 for pure water and seawater under one sun illumination. Moreover, salt crystallization predominantly occurs at the evaporator's edge and detaches spontaneously. Thus, the TPCD evaporator demonstrated efficient and stable desalination performance in the long term even when used to treat high-concentration brine. These findings highlight its promising applicability in the fields of desalination and water purification.