Scalable CO ₂ ‐Puffing Strategy for Fabricating High‐Performance Biomass Solar Evaporator

Scalable and energy‐efficient fabrication methods are essential for the practical deployment of solar‐driven interfacial evaporator. Herein, a novel and scalable CO 2 ‐puffing drying strategy is presented to construct high‐performance biomass‐based solar evaporator with hierarchical porous architectures. Compared to traditional freeze‐drying, this method significantly reduces energy consumption and processing time while preserving mechanical integrity and enhancing pore interconnectivity. The resulting carbonized potato evaporator, further functionalized with poly (sodium 4‐styrenesulfonate) (PNaSS), exhibits exceptional photothermal performance, achieving an evaporation rate of 3.46 kg∙m −2 ∙h −1 and a solar‐to‐vapor conversion efficiency of 98.67% under 1 sun. The multiscale interconnected pore structure promotes rapid water transport, effective salt backflow, and thermal localization. Notably, the evaporator shows excellent salt resistance and long‐term stability during cyclic operation and outdoor testing. This work offers a cost‐effective and scalable pathway for producing bio‐derived solar evaporator, providing new insights into sustainable freshwater harvesting and desalination technologies.