An Ultrathin Flexible 2D Membrane Based on Single‐Walled Nanotube–MoS₂ Hybrid Film for High‐Performance Solar Steam Generation

TLDR

Solar steam generation relies on floating photothermal materials, but efficiency is limited by the difficulty of producing ultrathin materials that absorb the full solar spectrum. The study presents an ultrathin 2D porous photothermal film made from MoS₂ nanosheets and single‑walled nanotubes, proposing a new strategy for 2D nanomaterials in solar energy harvesting and related technologies. The hybrid film is fabricated by integrating MoS₂ nanosheets with SWNTs into a porous 2D structure that, when floating on water, creates a sharp temperature gradient through localized heat confinement. The SWNT–MoS₂ film absorbs more than 82 % of the solar spectrum at an ultrathin thickness of ≈120 nm, achieves 91.5 % evaporation efficiency, and remains stable for at least 20 illumination cycles while maintaining high salt‑rejection performance.

Abstract

Abstract Solar steam generation is achieved by localized heating system using various floating photothermal materials. However, the steam generation efficiency is hindered by the difficulty in obtaining a photothermal material with ultrathin structure yet sufficient solar spectrum absorption capability. Herein, for the first time, an ultrathin 2D porous photothermal film based on MoS 2 nanosheets and single‐walled nanotube (SWNT) films is prepared. The as‐prepared SWNT–MoS 2 film exhibits an absorption of more than 82% over the whole solar spectrum range even with an ultrathin thickness of ≈120 nm. Moreover, the SWNT–MoS 2 film floating on the water surface can generate a sharp temperature gradient due to the localized heat confinement effect. Meanwhile, the ultrathin and porous structure effectively facilitates the fast water vapor escaping, consequently an impressively high evaporation efficiency of 91.5% is achieved. Additionally, the superior mechanical strength of the SWNT–MoS 2 film enables the film to be reused for atleast 20 solar illumination cycles and maintains stable water productivity as well as high salt rejection performance. This rational designed hybrid architecture provides a novel strategy for constructing 2D‐based nanomaterials for solar energy harvesting, chemical separation, and related technologies.