Interfacial Solar Steam Generation Enables Fast‐Responsive, Energy‐Efficient, and Low‐Cost Off‐Grid Sterilization

Abstract Steam sterilization is widely used as one of the most reliable sterilization methods for public health. However, traditional steam sterilization mainly relies on electricity, a constrained resource for many developing countries and areas. The lack of available and affordable sterilization techniques in these areas is exposing human beings to a high risk of various epidemic diseases, and calls for the development of off‐grid sterilization solutions. For the first time, the kinetic advantages of interfacial solar steam generation is fundamentally revealed and it is demonstrated that interfacial solar steam generation can enable fast‐responsive (as short as 8.4 min for a full sterilization cycle) and energy‐efficient (100 J mL −1 for steam reaching 121 °C) sterilization, superior to those of the conventional sterilization techniques. The key solar absorber is made of low cost and widely available biochar. A proof‐of‐concept sterilization system with a 10.5 L solar autoclave is built with very low cost of whole life‐cycle and operates with minimum carbon footprint. Effective sterilization (≈99.999999% inactivation of pathogen), exceeding the requirements of Food and Drug Administration is demonstrated, making the sterilization strategy a promising and complementary personalized sterilization solution, particularly beneficial for off‐grid areas.