Method for preparing two-dimensional nanosheets by microwave-assisted liquid phase stripping of layered material

Abstract

The invention discloses a method for preparing two-dimensional nanosheets by microwave-assisted liquid phase stripping of a layered material. The method comprises the following specific steps: 1) carrying out wet grinding of precursor powder of the layered material with a liquid medium in a mortar; 2) washing the wet-ground mixture with a same liquid medium and transferring into a microwave reaction tube; 3) placing the microwave reaction tube into a microwave reaction device, and carrying out microwave irradiation; 4) after microwave irradiation, washing and filtering the microwave mixture, and collecting a filter membrane; 5) carrying out ultrasonic dispersion of the obtained filter membrane in an organic solvent, and carrying out centrifugal separation, wherein a supernatant is a nanosheet dispersion liquid, and a precipitate is a separated unpeeled phase; and 6) filtering the obtained nanosheet dispersion liquid, collecting a filter membrane, and carrying out vacuum drying to obtain the nanosheet powder. The method is universal, fast and efficient in peeling various layered materials, and the prepared nanosheets are ultra-thin, large in size, small in peeling size reduction andhigh in chemical stability, and have broad application prospects in basic scientific researches, electronics, catalysis, energy, sensing and other hot fields.

Description

technical field [0001] The invention belongs to the field of nanomaterial preparation, and in particular relates to a general microwave-assisted liquid-phase exfoliation layered material to realize rapid and efficient preparation of single-layer / few-layer, large-scale, and high-chemical-stability two-dimensional nanosheets. Background technique [0002] Two-dimensional nanosheets refer to sheet-like nanomaterials with a lateral dimension of hundreds of nanometers to several micrometers and a thickness of only a few or even a single atomic layer. Since Novoselov and Geim et al. glued graphene from graphite with transparent glue in 2004, two-dimensional materials have large specific surface area and many nano-effects due to their atomic-level thickness and large horizontal / longitudinal size ratio. Excellent electrical, optical, magnetic, and mechanical properties have broad application prospects in the fields of catalysis, energy, sensing, and electronics, and provide rich res...

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Problems solved by technology

Among them, the ion pre-intercalation / exchange-assisted method, due to the introduction of the "pre-expansion" mechanism, makes the yield of nanosheets higher, but the ion intercalation / exchange is only suitable for some layered materials, and the intercalation media selected are mostly Active alkali metal elements such as lithium, sodium, and potassium are highly dangerous and time-consuming to operate (Nanoscale 2014, 6, 12458-12462)

Mechanical force assistance, such as ultrasonic-assisted liquid phase exfoliation, is currently the most widely used liquid phase exfoliation method, but due to continuous ultrasonic action, the size of the obtained nanosheets is severely reduced, and structural defects are easily introduced, and the proportion of single-layer nanosheets is low (Science 2011, 331, 568-571)

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