Highly Thermal Insulated and Super-Hydrophilic Corn Straw for Efficient Solar Vapor Generation.

Biomass-derived photothermal conversion materials are considered as one of promising evaporator choices for cost-effective, sustainable, and environment-friendly solar vapor generation. Herein we demonstrate a double-layer flamed straw, which is a typical solar-driven interfacial evaporator that can be directly convert solar energy into heat, and then localize heat at interface for vapor generation. Benefiting from the unique structure of natural corn straw, the flamed straw exhibits high solar absorbance of 91%, ultra-low thermal conductivity (0.042 W m-1 K-1), and the sufficient water supply. Notably, the flamed-straw evaporator achieves a fast evaporation rate of 1.497 kg m-2 h-1 and high photothermal efficiency of 86% under one sun illumination, showing a comparable efficiency with ever reported studies. Our work highlights the promise of using the low-cost biomass-derived materials as highly effective solar vapor generators in the realm of seawater desalination and wastewater treatment.