Interfacial evaporation device based on melamine foam supported MOFs-derived CuS nanosheets for highly efficient water evaporation

Sunlight-driven interfacial evaporation has been considered an effective solution to address water scarcity and seawater desalination with minimal environmental impact. We designed a sunlight-driven interfacial evaporation device using the porous melamine foam (MF) as the carrier to stabilize the loading of metal−organic frameworks (MOFs) derived CuS nanosheets. The MOFs-derived CuS nanosheets (M-CuS) have a full-spectrum solar light absorption rate of 95% and the porous channels existing inside M-CuS effectively improve the light capturing ability and contribute to the rapid thermal response of M-CuS. The M-CuS was loaded on the MF through the adhesion of polyvinyl alcohol (PVA) to obtain an integrated M-CuS/MF aerogel with a stable structure. PVA further improves the hydrophilicity of MF and ensures a continuous supply of water to M-CuS/MF during the evaporation process. The unique porous structure of M-CuS/MF further promotes the absorption of sunlight, and the low thermal conductivity of MF (0.036 Wm-1K-1) could reduce the radiative and convective heat loss from the material to the surrounding environment. The evaporation rate and photothermal conversion efficiency of CuS/MF are 1.46kgm-2h-1 and 86% under one sunlight, respectively. The continuous seawater evaporation cycle experiments (15 times) show that the device can maintain a stable evaporation rate. The excellent salt blocking performance of M-CuS/MF suggest the promising long-term stable desalination applications.