3D‐Printed Architected Anisotropic Channels for Ultrafast Solar‐Driven Interfacial Evaporation via Localized Thermal Management and Water Layer Structuring

ABSTRACT Efficient solar‐driven interfacial evaporation requires coordinated photon absorption, heat confinement, and directional water delivery, yet current directional evaporators rarely achieve materials‐level anisotropy to regulate photon‐phonon‐water coupling. Here, we report a 3D‐printed anisotropic channel architecture (a‐BTCG) that co‐engineers directional geometry with preferential alignment of Ti 3 O 5 nanoparticles, boron nitride (BN) nanosheets, and chitosan to form an integrated transport framework. The a‐BTCG delivers a high evaporation rate of 5.43 kg m −2 h −1 under 1 sun and maintains stable performance for over 200 h in 20 wt.% NaCl, enabled by fast water flux (1.13 × 10 −2 µm 3 s −1 ) and enhanced in‐plane thermal conductivity (2.73 W m −1 K −1 ). Mechanistic investigations reveal that aligned BN establishes continuous phonon‐guided thermal pathways for heat localization, while the Ti 3 O 5 –BN hybrids enhance broadband absorption via reduced reflectance and multireflection in oriented channels. Chitosan mediates interfacial water structuring, lowers effective evaporation enthalpy, and sustains salt‐resistant replenishment. The combined structural and materials‐level anisotropy, therefore, overcomes conventional trade‐offs in light absorption, heat dissipation, and water supply. This work demonstrates the potential of 3D printing–assisted alignment engineering for high‐performance solar evaporators and provides a generalizable platform for advanced desalination and environmental thermal‐management technologies.