3D vertically oriented array channel starch/CuS aerogel inspired via tree trunk vessel structure for efficient all-weather solar steam generation and water purification

Solar-driven interfacial evaporation is an economical and environmentally friendly technology for freshwater collection and an important strategy to address water shortages and pollution. However, evaporators face serious challenges in achieving efficient desalination and all-weather freshwater collection. Here, inspired by the xylem catheter structure of the trunk, large-pore channels of millimeter-scale vertical array structures are constructed in a starch aerogel evaporator through a 3D printing mold and nanoCuS is loaded inside the aerogel. The strong hydrophilicity of starch/CuS aerogels (P-SA@CuS) and multiple light absorption of internal micro-nano pores can utilize sunlight to obtain heat while providing directional and sustainable water supply to achieve photothermal moisture evaporation. The millimeter-scale vertical array channels enhance water evaporation and photothermal conversion, resulting in rapid desalination and high-efficiency water purification in high-concentration saline solutions. The P-SA@CuS evaporator cycles photothermal evaporation at a high saline concentration (15 wt% NaCl), and its evaporation rate remains above 2.79 kg m −2  h −1 , and there is no salt deposition on the surface. Simultaneously, P-SA@CuS exhibits a lower thermal conductivity (0.21 W m −1  K −1 ) under humid conditions, which helps reduce nighttime heat loss and enables all-weather freshwater collection. During all-weather continuous photothermal water evaporation outdoors (daytime and nighttime), the evaporation rate remains above 22.8–26.2 kg m −2 . The P-SA@CuS evaporator not only achieves effective purification of various non-drinking water (sodium chloride solutions, acid and alkali solutions, dye wastewater, heavy metal wastewater, simulated seawater), but also employs nano CuS to catalyze the degradation of antibiotics in water. This study provides new strategies for starch aerogels in efficient desalination and water purification, as well as all-weather freshwater collection.