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

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 Ti₃O₅ 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 µm³ 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 Ti₃O₅-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.