A water supply tunable bilayer evaporator for high-quality solar vapor generation.

Interfacial heating is the most obvious feature that distinguishes the novel solar driven interfacial heating from the traditional solar heating technology, and it is also a key factor in promoting solar energy utilization and vapor generation performance. However, the inherent trade-off between water supply and the interfacial heating performance of photothermal materials has rarely been investigated. Herein, an all-in-one designed bilayer evaporator consisting of a top solar absorber (FeO@PDA-SA) and a bottom water transport layer (SA) is reported. This bilayer structured aerogel can provide good thermal insulation, effective water transmission channels, and reliable light absorbance, and perform well as a high-quality solar steam evaporator with the evaporation rate of approximately 1.517 kg m h and the evaporation efficiency of approximately 98.27% under 1 kW m solar illumination. Most importantly, we can control the pore size of the bottom layer by a simple free water evaporation method, so as to manipulate the water transport capacity of materials. There is flexibility to change the water content of the light-absorbing structure and further explore the influence of water supply on the interfacial heating performance of the evaporator, which provides more possibilities for the design and preparation of high-quality solar steam evaporators.