Excellent energy capture of hierarchical MoS2 nanosheets coupled with MXene for efficient solar evaporators and thermal packs

Abstract

Solar water evaporation technology has become one of the promising ways for seawater desalination by excellent energy capture and efficient solar-thermal conversion. However, some challenges still restrict its further industrial development, such as low flexibility, non-portability, and insufficient energy utilization, salt crystallization problems. In this work, hierarchical MoS2 nanosheets coupled with MXene (MoS2-MXene) is constructed and formed into a film with foldability and portability for solar water evaporation. Improved evaporation rate (2.5 kg m−2 h−1) is observed due to enhanced energy capture from a folded 3D solar evaporation system. Meanwhile, the outstanding evaporation performance (3.2 kg m−2 h−1) is realized because of gradient heating from a hydrophobic MoS2-MXene@PF (MoS2-MXene@Paraffin) under one sun. During the evaporation of high-concentration NaCl solution (20 wt%), the hydrophobic layer is observed to become a salt crystallization site for salt generation. After long-term and multiple testing, no salt crystallization was found at the evaporation site, maintaining a stable evaporation rate. More interesting, MoS2-MXene@PF can be also succeeded as a solar thermal pack for storing heat through the phase change material paraffin (PF). This work provides a new solution to realize excellent energy capture for solar desalination and solar thermal storage.