A New Strategy for Preparing Two-dimensional Nanomaterials by Exfoliating LDH Using Supercritical Ethanol

A new strategy to exfoliate layered double hydroxide (LDH) by using supercritical ethanol is presented. The procedure involves intercalation of anionic surfactant into the decarbonated LDH by ion exchange, followed by an exfoliation of the surfactant-intercalated LDH in supercritical ethanol. With this new strategy, two-dimensional (2D) nanosheets with a thickness of 2–4 nm and lateral dimensions of several microns are obtained. The preparation method of the 2D nanosheets is simple and environmentally friendly. With this new strategy, the two-dimensional (2D) nanosheets with a thickness of 4 nm and lateral dimensions of several or even a dozen microns are obtained. TEM shows weak but uniform contrast indicates that the lamellae are very thin and uniform in thickness. AFM clearly shows the morphology of LDHs after exfoliating, and it can produce Tindal phenomenon.