Continuous Freshwater Collection in Arid Regions via Radiative Cooling and Solar-Driven Dual-Mode Atmospheric Water Harvesting

The freshwater crisis poses a significant threat to human survival, particularly in arid desert regions. Conventional technologies, such as fog harvesting and atmospheric water harvesting, face limitations, including low efficiency, environmental constraints, and intermittent operation. To address these challenges, we propose a portable dual-mode atmospheric water harvester that synergistically integrates radiative cooling and solar-driven adsorption technologies to achieve continuous freshwater production. At night, it uses radiative cooling and a surface with heterogeneous wettability to enhance atmospheric water collection and facilitate directional transport. This mode achieves a maximum water collection rate of 0.388 g·cm^-2·day^-1. During the day, it relies on solar-powered adsorption for moisture harvesting, with a maximum water collection rate of 1.61 g^-1·g^-1·day^-1. The maximum daily water output per cycle of the device reaches 7.79 g·day^-1 (the area of the radiative cooling material is 16 cm², and the adsorption material is 1 g). This dual-mode synergistic design provides an efficient and continuous solution for water harvesting in desert environments.