Heat‐Localized and Salt‐Resistant 3D Hierarchical Porous Ceramic Platform for Efficient Solar‐Driven Interfacial Evaporation

Abstract Solar‐driven interfacial evaporation (SDIE) is a highly promising approach to achieve sustainable desalination and tackle the global freshwater crisis. Despite advancements in this field, achieving balanced thermal localization and salt resistance remains a challenge. Herein, the study presents a 3D hierarchical porous ceramic platform for SDIE applications. The utilized alumina foam ceramics (AFCs) exhibit remarkable corrosion resistance and chemical stability, ensuring a prolonged operational lifespan in seawater or brines. The millimeter‐scale air‐filled pores in AFCs prevent thermal losses through conduction with bulk water, resulting in heat‐localized interfaces. The hydrophilic nature of macroporous AFC skeletons facilitates rapid water replenishment on the evaporating surface for effective salt‐resistant desalination. Benefiting from its self‐radiation adsorption and side‐assisted evaporation capabilities, the AFC‐based evaporators exhibit high indoor evaporation rates of 2.99 and 3.54 kg m −2 h −1 under one‐sided and three‐sided illumination under 1.0 sun, respectively. The AFC‐based evaporator maintains a high evaporation rate of ≈2.77 kg m −2 h −1 throughout the 21‐day long‐term test. Furthermore, it achieves a daily water productivity of ≈10.44 kg m −2 in outdoor operations. This work demonstrates the potential of 3D hierarchical porous ceramics in addressing the trade‐off between heat localization and salt resistance, and contributes to the development of durable solar steam generators.