Carbon nano-allotropes produced by ultrasonication of few-layer graphene and fullerene

We report on the formation of fullerites, nano-onions, and nanodiamonds by ultrasonication of few-layer graphene (FLG) and fullerene (C60) in N,N-Dimethylformamide (DMF). The ultrasonication of C60 molecules in DMF produces large quantities of face-centred cubic fullerites (fcc) with a cell parameter of 1.42 nm and very narrow diameter distribution (22 ± 3 nm). The addition of FLG during the ultrasonication process additionally to fullerites, yields to the formation of defective nano-onion structures mainly at edges of the graphene sheets. Increasing the ultrasonication time under the addition of C60, prompts the formation of carbon nanodiamonds deposited on the surface of fullerites. From experimental analysis, it is concluded that the extreme conditions generated by acoustic cavitation provoke the formation of defective nano-onions through the auto-assembly of small graphene pieces directed by π-π stacking interactions onto C60. These particles are then converted into more stable nano-diamonds during ultrasonication. Our results suggest the existence of unexplored mechanisms for carbon nano-allotropes nucleation and growth. © 2015 Elsevier Ltd. All rights reserved.

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