Scalably fabricated Janus ultra-black composite film with visible-light/electric/microwave triple-responsiveness

Multi-functional integrated smart interface evaporator for seawater is widely viewed as highly promising technology to generate clean water. Herein, the scalable Junas ultra-black composite film with visible-light/electric/microwave triple-responsiveness was fabricated by spraying an ultra-black coating onto modified carbon nanotube film, enabling all-weather purification of seawater. Analysis of microstructure, morphology and performance revealed that the Junas structured ultra-black composite film possessed excellent hydrophilicity/hydrophobicity and hierarchical micro-nano three-dimensional porous structure, facilitating water transport via capillary effect and significant photothermal phenomenon with 51.2 °C under 1 kW/m 2 illumination. Consequently, the ultra-black composite film evaporator offered superior photothermal water evaporation performance with evaporation rate of 1.25 kg·m −2 ·h −1 , thermal conversion efficiency of 82.18 % and exceptional cycling stability, along with all-weather electrothermal seawater desalination with evaporation rate of 3.51 kg·m −2 ·h −1 and photo−/electrothermal seawater desalination with evaporation rate of 4.65 kg·m −2 ·h −1 . Additionally, the evaporator can effectively purify seawater, yielding water with metal ion concentrations significantly below the limits stipulated in the World Health Organization drinking water standards. Simultaneously, the hierarchical micro-nano porous ultra-black coating coupled with the highly conductive carbon nanotube layer endows it with outstanding electromagnetic shielding effectiveness of ∼48 dB in the 8–12 GHz band. This work presents a facile strategy for designing scalable, triple-responsive ultra-black composite film, achieving integrated all-weather desalination of seawater and electromagnetic protection through the synergistic integration of hierarchical micro-nano three-dimensional porous structure and hydrophilic carbon nanotube film.