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 MoS 2 /graphene oxides (GO) can significantly enhance the evaporation efficiency and solve the problem of fouling. First-level leaf-like MoS 2 /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 m 2 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 MoS 2 and GO interlayers and the nanoporous surface. The biomimetic evaporator indicates a potential direction through surface/interface regulation of photothermal nanomaterials for water desalination.

Tree-Inspired Structurally Graded Aerogel with Synergistic Water, Salt, and Thermal Transport for High-Salinity Solar-Powered Evaporation

“…Several strategies have been developed to tackle the salt accumulation issue through decoupling water, salt, and thermal transports, including Janus surface design [ 29 , 30 ], ion rejection [ 17 , 31 , 32 ], salt localization [ 23 , 33 ], and diffusive/convective backflow [ 12 , 34 – 37 ]. The Janus design stacked hydrophobic photothermal layer and hydrophilic water absorbing layer in tandem to prevent brine transport onto the photothermal surface.…”

Promoting Volumetric Desalination Rate and Capacity via Highly Oriented, Densified Graphene Architectures

“…This indicates that both RDG and HODG3 have oxygen-containing functional groups. The Raman spectra of RDG and HODG3 reveal strong G bands at 1590 cm –1 and D bands at 1350 cm –1 (Figure b). − The I D /I G ratios of RDG and HODG3 are 0.93 and 0.98, respectively, which indicates that HODG3 has more structural defects than RDG owing to the chemical etching of KOH during the hydrothermal process. The energy dispersive X-ray spectroscopy (EDS) results reveal that the oxygen content of HODG3 (22.76%) is higher than that of RDG (18.93%) (Figure c).…”