Synergizing Hierarchical Pores and Three‐Dimensional Geometry in Diatomite Ceramics for Efficient Solar Evaporation

Solar‐driven interfacial evaporation is a promising approach for freshwater production, yet its rate is limited by the competing requirements of thermal localization and continuous water supply. Hydrophobic photothermal coatings can confine heat at the evaporation front, but when applied as continuous layers on planar substrates they restrict water replenishment and vapor release. Here, a sacrificial template‐assisted imprinting strategy is used to convert low‐cost diatomite and paraffin wax into hierarchically porous ceramics with asymmetric wettability and engineered three‐dimensional geometry. Paraffin acts as both a shaping binder and a pore‐forming template, producing a multiscale pore network that supports rapid capillary transport. The imprinted surface interrupts the continuity of the soot‐based photothermal coating and introduces geometric discontinuities that serve as open channels for liquid supply and vapor escape. The resulting evaporator delivers an evaporation rate of 1.99 kgm −2 h −1 under one sun. This work demonstrates a scalable and solvent‐free route for transforming abundant mineral resources into high‐performance solar evaporators and provides a structural strategy for mitigating wettability‐related interface limitations in interfacial evaporation systems.