Flexible solar absorber using hydrophile/hydrophobe amphipathic Janus nanofiber as building unit for efficient vapor generation

Abstract

Solar vapor generation has become a promising technology for water harvesting owing to the abundant and costless solar energy. However, there still remains great challenges to improve the usability of solar absorbers and realize high-efficient vapor generation. Herein, novel solar absorber is constructed using electrospun hydrophilic cellulose acetate/hydrophobic polyvinyl butyral amphipathic Janus nanofibers as substrate. Owing to the unique composition and structure, the electrospun Janus nanofibers film realizes the integration of water-pumping, thermal-resisting, self-floating, and salt-resisting functions in a monolayered film, which is desirable for designing solar absorbers. Highly efficient photothermal conversion material composed of carbon nanotubes, SiO2 nanoparticles and polydopamine is modified onto the surface of the Janus nanofibers film to obtain the solar absorber. With the solar absorber, a state-of-the-art water evaporation rate (2.398 kg m-2h−1) can be reached under 1 sun irradiation, and satisfactory reusability is guaranteed as well. Moreover, the solar absorber based on the Janus nanofibers film also shows promising desalination performance. The constructed solar absorber with excellent comprehensive performance provides potential strategy and new design philosophy for clean water generation.