A robust asymmetric porous SWCNT/Gelatin thin membrane with salt-resistant for efficient solar vapor generation

Abstract Solar vapor generation, as a promising technology for freshwater production, is achieved by localizing heat at water-air interface to drive water evaporate rapidly. Tremendous efforts have been paid to design high efficiency solar vapor generation devices, however, salt accumulation in practical use is still a troublesome problem to be solved. Herein, we present a novel asymmetric porous SWCNT/Gelatin membrane (SGM) via a facile and scalable vacuum filtration technology using low-cost materials. Owing to the use of in situ template-assisted pore-creating Cu3(BTC)2 (HKUST-1) MOFs and the crosslinking of gelatin, the SGM possesses hierarchical porous structures and robust mechanical strength. Meanwhile, the SGM presents a rough and porous upper surface for light absorption, and a dense and negatively charged gelatin thin layer at the bottom for salt-resistant. Based on the synergistic combination of carboxylic SWCNT and gelatin, the negatively charged SGM with a thickness of only 1.7 μm demonstrates a high solar-vapor generation efficiency of 92.0% under one sun (5.4 times higher than that of pure water), and an impressive long-time stability and reusability in seawater. This efficient solar vapor generation membrane improves the lifetime in seawater and promotes further practical applications.