Aqueous solutions of carbohydrates are new choices of green solvents for highly efficient exfoliation of two-dimensional nanomaterials

Deep eutectic solvents (DESs) have found great interest among researchers due to their green nature and lower costs compared to organic solvents and ionic liquids. Water, an essential component of most DESs, poses paramount impacts on the properties of these solvents. In the present study, we found that water can modulate the molecular arrangement of the solvent and affect the synthesis efficiency of both MoS2 and graphene nanosheets considerably. Using a low-cost mechanical exfoliation approach and response surface methodology, we achieved the synthesis yield of 87% for MoS2 nanosheets. We also succeeded in the production of few-layer graphene with the average lateral dimension of 3.5 mu m. We further showed that it is possible to dilute DESs by water and still retain the synthesis yield at reasonably high levels. In this way, the total cost of the exfoliation process reduces, particularly when it is aimed to synthesize large scales of two-dimensional nanomaterials. (C) 2020 Elsevier B.V. All rights reserved.