Facile synthesis of ultrathin lepidocrocite nanosheets from layered precursors

Ultrathin two-dimensional nanosheets have been widely studied because of their peculiar properties and promising applications. As a typical layered material, successful exfoliation of freestanding ultrathin lepidocrocite (γ-FeOOH) nanosheets from the bulk material has not been reported to date. Herein, we report a facile synthetic route to prepare ultrathin lepidocrocite nanosheets with a thickness of approximately 2-3 nm from FeOx -propanediol layered precursors through weakening of the hydrogen bonds during the crystallization process. The ultrathin morphology and single-crystal structure of the nanosheets were confirmed by transmission electron microscopy, X-ray diffraction, and atomic force microscopy. The formation process of these nanosheets demonstrated simultaneous exfoliation and crystallization of lepidocrocite in basic aqueous solution. The obtained ultrathin nanosheets exhibited a much lower Néel temperature (18.3 K) than bulk lepidocrocite and weak ferromagnetic behavior below this temperature.