Bifunctional photothermal membrane for high-temperature interfacial solar steam generation and off-grid sterilization

High-temperature solar steam generation is a promising sustainable strategy to alleviate the global clean water shortage. However, it is challenging to scale up the high-temperature steam generation under ambient conditions for water purification and steam sterilization simultaneously. Herein, we develop a solar-powered steam generating system to produce high-temperature steam for interfacial solar steam evaporation and off-grid sterilization. A three-layered photothermal membrane made of polystyrene foam, bubble wrap, and reduced graphene oxide (rGO) coated cloth produces high-temperature steam that can be condensed to clean water as well as sterilize microbes efficiently. The hybrid device configuration and higher solar light-absorbing capability of rGO result in high temperature steam generation (∼90 °C) to sterilize microorganisms such as S.aureus, E.coli, and G.stearothermophilus. Such a bifunctional device with high temperature steam generation and solar-steam evaporation capability could be a promising development for sustainable clean water generation and sterilization in remote areas.