Hierarchically Structured Self‐Floating Multilayer Evaporator Based on Polyaniline/Carbon Black Functionalized Carbon Fiber Paper for Efficient Solar Desalination

ABSTRACT Solar‐driven interfacial evaporation has emerged as a transformative technology for sustainable seawater desalination. While significant advancements have been made in enhancing evaporation rates through material selection and architectural optimization, mitigating parasitic heat loss remains a critical technical bottleneck. In this work, we present a hierarchically structured, self‐floating multilayer evaporator utilizing carbon fiber paper (CP) functionalized with polyaniline (PAN) and carbon black (CB) as the photothermal layer. The designed architecture leverages a delignified wood (DW) block as an efficient hydrophilic water‐pumping scaffold, coupled with a modified hydrophobic carbon paper (CP@PAN‐CB) to effectively localize heat and suppress downward conduction to the bulk water. Systematic investigation reveals that the sequential doping of PAN followed by CB creates a synergistically high‐dispersion interface that bolsters light‐harvesting efficiency. Under one‐sun irradiation (1 kW m −2 ), the evaporator attains a stable surface temperature of approximately 65°C within 60 s and achieves a peak evaporation rate of 1.593 kg m −2 h −1 in seawater. Furthermore, the system demonstrates exceptional long‐term stability with negligible salt crystallization over continuous 8‐h testing. This work highlights the potential of gradient hydrophilicity and optimized photothermal functionalization for robust and efficient solar‐driven water purification.