关键词: 气凝胶, 芳纶纳米纤维, 二硫化钼, 纳米银粒子, 界面蒸发, 光热转换

Abstract: With the global shortage of water resources and the increasingly severe energy crisis, solar interface evaporation technology, as an innovative solution, is gradually becoming a research hotspot. The solar interface evaporation system must have three key elements: efficient photothermal conversion materials, excellent hydrophilicity and reasonable thermal management structure design. First of all, efficient photothermal conversion materials are the basis. They must be able to effectively absorb sunlight and convert it into heat energy. Ideal materials such as graphene, carbon nanotubes, metal nanoparticles and polymer composites should have high light absorption, good thermal stability and long-term durability. Secondly, the design of hydrophilic surface is crucial to accelerate the transmission of water to the evaporation surface, which can be achieved by introducing hydrophilic groups or constructing micro nano structures on the material surface. Finally, the reasonable thermal management structure design ensures that the absorbed heat is mainly concentrated on the evaporation surface, rather than lost to the environment. By using thermal insulation materials or building multi-layer structures, such as isolating the photothermal conversion layer from the water body, the heat can be effectively locked at the evaporation interface, so as to improve the evaporation efficiency. 
The complex structural design of the solar evaporation system limits its large-scale production and cost-effectiveness. The large specific surface area, high porosity, extremely low thermal conductivity and excellent hydrophilicity of the aramid nanofiber aerogel meet the requirements for the preparation of an integrated solar evaporation system. In this paper, the ice template method was used to construct MoS2/AgNPs@ANFs composite aerogels with porous cellular skeleton structure. The nano porous structure increases the refraction path of the optical path, enhances the light scattering, and improves the light absorption ability. The absorbance in the visible region reaches 93.58%; the cellular structure improves the capillary effect, effectively improves the water transmission capacity, and provides a path for water vapor transmission; the density of multi-stage porous aerogels is as low as 10 mg/cm3, and the aerogels have the ability of self-floating and provide the basis for rapid evaporation rate; the porous cellular skeletal structure limits the heat convection and heat conduction, resulting in an extremely low thermal conductivity, which is conducive to the heat management of interface evaporation; MoS2/ AgNPs@ANFs composite aerogels are hydrophilic. Under the irradiation of five times of sunlight, the surface temperature rises to 74.66 ℃, and the maximum evaporation rate of water vapor is 11.7 kg/(m2·h). The evaporation rate remains stable in six cycles, which provides a data basis for the structural design of solar interface water evaporator.
Solar evaporation technology, with its characteristics of high efficiency, low cost and environmental protection, provides a sustainable solution for the global water shortage and energy crisis. With the continuous progress and innovation of technology, solar evaporation technology will play a more important role in the field of water purification and energy conversion in the future.

Key words: aerogel, aramid nanofibers, MoS2, nanosilver particles, interfacial evaporation, photothermal conversion