LAUSR

Interfacial solar steam generation (ISSG) employed for seawater desalination and wastewater purification shows great promise to alleviate global freshwater scarcity. However, simultaneous optimization of water transfer direction in a cost‐effective and reliable ISSG to balance thermal localization, salt accumulation, and resistance to oilfouling represents a rare feat. Herein, inspired by seabird beaks for unidirectional water transfer, eco‐friendly and cost‐effective plant extracts, sodium alginate, and tannic acid, are selected for crafting an innovative Sodium Alginate‐Tannic Acid Hemispheric Evaporator (STHE). The STHE aligned with centripetally tapered channels ensures one‐directional water flow and effectively inhibits downward heat transfer, thereby boosting energy efficiency. Additionally, the integration of one‐way water supply in tapered channels with interfacial evaporation of STHE, mimicking plant transpiration, collaboratively facilitates upward water transfer for a reliable solar‐driven water evaporation rate of ≈2.26 kg m−2 h−1 under one sun irradiation. Even in a brine of 15.0 wt % solution, no salt crystals are observed on the surface of STHE. Hemispheric structure and superhydrophilicity are conducive to oil repellence. This work provides pivotal inspiration for constructing next‐generation solar generators of high‐efficiency, salt‐tolerance, and anti‐oil‐fouling.