Magnetically driven Janus conical vertical array for all-weather freshwater collection

Abstract

The engineering of multifunctional structures with special surface wettability is highly desirable for all-weather freshwater production, but relevant research is scarce. In this study, a Janus conical vertical array was designed and fabricated via a magnetically driven spray-coating method for the first time. Benefiting from the special structure and wettability enhancement of the array in terms of solar absorption, fog capture and merging, droplet movement and evaporation area, all-weather freshwater production consisting of high-quality daytime solar vapor generation (water evaporation rate approximately 2.43 kg m⁻² h⁻¹, 1 kW m⁻²) and nighttime fog collection (water collection rate approximately 3.536 g cm⁻² h⁻¹) can be realized concurrently. When the designed array is employed for outdoor environments (114°35′E, 30°38′N, average daily temperature 34.9 °C, average daily humidity 64.0%), reliable and efficient daily pure water yields of 19.13 kg m⁻²–26.09 kg m⁻² are obtainable. We believe that the proposed strategy for fabricating a Janus conical vertical array is novel in the integration of solar vapor generation and fog collection, which has great significance for all-weather freshwater production.