Enhancing Solar-Driven Water Purification by Multiscale Biomimetic Evaporators Featuring Lamellar MoS2/GO Heterojunctions.

ABSTRACT

Solar-powered steam generation holds a strong sustainability in facing the global water crisis, while the production efficiency and antifouling performance remain challenges. Inspired by river moss, a multiscale biomimetic evaporator is designed, where the key photothermal conversion film composed of lamellar MoS2/graphene oxides (GO) can significantly enhance the evaporation efficiency and solve the problem of fouling. First-level leaf-like MoS2/GO nanosheets, obtained by a modified hydrothermal synthesis with an assisted magnetic-field rotation stirring, are self-assembled into a second-level nanoporous film, which achieves an evaporation rate (ER) of 1.69 kg m-2 h-1 under 1 sun illumination and an excellent self-cleaning ability. The tertiary-bionic evaporator with a macroscopic crownlike shape further enhances the ER to 3.20 kg m-2 h-1, 189% above that of planar film, yielding 20.25 kg m2 of freshwater from seawater during a daytime exposure of 6 h. The exceptional outcomes originate from the macroscopic biomimetic design and the microscopic integration of heterojunction interfaces between the MoS2 and GO interlayers and the nanoporous surface. The biomimetic evaporator indicates a potential direction through surface/interface regulation of photothermal nanomaterials for water desalination.