Efficient exfoliation of bulk MoS2 to nanosheets by mixed-solvent refluxing method

•A new method was proposed to prepare MoS2 nanosheets with a few good crystalline layers.•The new method is cheap, environment-friendly and easy to obtain MoS2 nanosheets.•MoS2 nanosheets show much better photocatalytic activity of H2 production than bulk MoS2.

In this work, we reported a versatile and environmental-friendly mixed-solvent refluxing method to prepare MoS2 nanosheets with few layers by exfoliation of bulk MoS2 for the first time. The optimal synthetic conditions, including refluxing temperature, time and the volume ration of ethanol/water, were investigated according to the results of photocatalytic H2 evolution from water splitting. The results show that the optimal conditions involve refluxing in 30% ethanol/water solution at 80 °C for 3 h. And the as-prepared MoS2 nanosheets show much better photocatalytic properties than bulk MoS2. The rate of photocatalytic H2 evolution is 176.7 μmol g−1 h−1 over the MoS2 nanosheets synthesized under the optimal conditions, whereas the rate of H2 production is only 21.8 μmol g−1 h−1 over the bulk MoS2. In addition, some characterization studies demonstrate the MoS2 nanosheets have been successfully prepared by using the mixed-solvent refluxing method. The present work opens a new avenue to obtain two-dimensional nanosheets with single or few layers, such as the layered transition metal dichalcogenides.

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