Highly Efficient Solar-Driven Interface Water Evaporation Achieved on Polypyrrole@Single-Sided Flannel

Solar interface evaporation is considered an innovative and effective technology for combating global freshwater scarcity, with its effectiveness primarily hinging on the efficiency of photothermal materials. Here, we designed a solar evaporation device comprising a sponge layer for water collection and a polypyrrole (PPy) layer chemically deposited on a single-sided flannel (PPy@SSF) for sunlight absorption. The fiber array within PPy@SSF facilitates to absorb light energy, establishing a heating interface between the light absorption layer and the water. The sponge layer not only aids in water collection but also serves as a thermal insulation layer, preventing heat dispersion. The resulting device exhibits characteristics such as high water evaporation, robust stability, and resistance to salt. The daily water output reaches 8.12 kg m–2 under direct sunlight. In desalinating simulated seawater, the ion concentrations in the condensed water were reduced by 4 orders. Furthermore, heavy metal ions in purified water from sewage were reduced by at least 3 orders of magnitude. Additionally, the properties of the device showed no attenuation after being used repeatedly 10 times under 1 sun. Our research provides a platform with high photothermal conversion efficiency for seawater and sewage purification.