Construction of a biomimetic wood structure with cellulose nanofiber/molybdenum disulfide hybrid aerogel for highly-efficient solar-driven interfacial evaporation

Abstract

Solar-driven interfacial water evaporation is a promising solution to water scarcity and pollution problems because it can efficiently convert solar energy into thermal energy and produce sustainable clean water. In this work, inspired by the multi-channel structure in the xylem of plants, cellulose nanofibers (CNF) and molybdenum disulfide (MoS2) nanosheets were selected to construct CNF/MoS2 nanosheets aerogel (CMoA) with vertical pores by directional freeze-drying method. Then we utilized the aerogel as an interfacial solar evaporator. The super-hydrophilic and internal vertical pore structure of this evaporator gives CMoA a high capacity to store and transport water, with a water evaporation rate of 1.81 ± 0.06 kg·m−2·h−1 under 1 sun. The vertical pore structure and the strong ability to transport water of the evaporator also enable the salt on the evaporator surface to diffuse into the bulk water in time, without causing salt deposition. Therefore, CMoA has high salt resistance and stability and can achieve fast evaporation even in high-concentration salt water. In addition, CMoA can also produce water at a rate of up to 10.3 kg·m−2 per day in the outdoor environment. By combining the natural bio-based material CNF with the biomimetic wood structure of aerogel, CMoA has a facile water transport process similar to that of plants. Moreover, our CMoA is a monolayer structure, which makes the preparation process simple and less costly. These multiple advantages make CMoA a promising application for future practical desalination work.