Rational 3D Coiled Morphology for Efficient Solar-Driven Desalination

Aiming at the global water scarcity, solar-driven desalination based on photothermal materials is identified as a promising strategy for freshwater production because of sustainability, spontaneity, and flexibility. Water transfer in photothermal materials, especially ones with 3D morphologies, can adjust the evaporation efficiency as a critical factor. In this work, a rationally designed roll morphology has been introduced into photothermal to advance the water transfer evaporation via controllable capillary action. The vertical intervals of the roll, similar to slit pore, can pump the water up to the entire materials to not only keep a stable vapor generation rate but reject salt precipitation. Additionally, the roll morphology also improves the light-harvesting via both the high roughness surface and confinement absorption inside the intervals. With excellent water transfer and energy management, photothermal roll showed an evaporation rate up to 1.93 ± 0.05 kg m^-2 h^-1, which was over 44% higher than the flat sample in the same constituents. Under actual conditions, the freshwater generation rate was achieved up to 1.09 kg m^-2 h^-1 on average of the whole daylight hours. The work provides novel insights into the design of efficient morphology in photothermal materials and advances their practical applications in sustainable water generation.