Facile and novel preparation of 2D-MoS2/carbon nanodots composite with high adsorption efficiency and capacity for dye removal

Here, hydrophobic bulk molybdenum disulfide (MoS2) was efficiently exfoliated into two dimensional (2D) nanosheets assisted with amphiphilic carbon nanodots (CNDs) in pure water. The optimized concentration of obtained 2D-MoS2 is as high as 0.41 mg/mL, which is higher than that of reported literatures. The average lateral size and layer number of 2D-MoS2 is 142.6 (±2.3) nm and 4, respectively. The characterizations and simulation demonstrated that CNDs can be instantly adsorbed on the surface of 2D-MoS2 and form 2D-MoS2/CNDs composite. Thus, after standing for 1000 h, the concentration of 2D-MoS2 still accounts for 90 % of the initial concentration with the help of CNDs. Further, this technique can also be used to prepare graphene and 2D-WS2 nanosheets. 2D-MoS2/CNDs composite as adsorbent showed excellent adsorption capacity (1136.9 mg/g) and ultrafast adsorption rate (1 min) for methylene blue removal, which benefits from abundant adsorption sites and high dispersion. This work not only develops a facile and universal technique for green preparation of 2D nanomaterials in one pot, but also provides a promising adsorbent for removing organic pollutants from aqueous solution.