High-Efficiency Solar Vapor Generation Boosted by a Solar-Induced Updraft with Biomimetic 3D Structures.

Sunlight-based desalination is one of the most environment-friendly, low-cost methods for obtaining freshwater on the planet. We implemented a biomimetic three-dimensional (3D) solar evaporator, improved by a solar-induced air-flow updraft. A carbon-coated polyvinyl alcohol (PVA) foam allowed us to achieve perfect absorption of ultrabroadband sunlight and continuously provide water to tall 3D structures. Integrating the convection flower (Amorphophallus titanum) and solar chimney structure, we proposed a bio-inspired 3D solar evaporator system that generates an updraft airflow. This updraft replaces saturated vapor between neighboring PVA foams with dry air, resulting in a significant increase in the effectiveness of dry air-water contact interfaces. Under the 1 sun condition (1 kW m-2), we achieve a high solar-vapor conversion efficiency of 95.9%.