[Show abstract][Hide abstract] ABSTRACT: Disclosed are methods for forming carbon nano-onions. The methods include annealing a carbon nanodiamond starting material in an inert atm. The method can be carried out at ambient pressure. Also disclosed are methods for functionalizing carbon nano-onions. For instance, carbon nano-onions can be functionalized so as to be sol. in aq. or org. solvents, as desired. Also disclosed are methods for sepg. mixts. of carbon nano-onions. In particular, mixts. of carbon nano-onions can be sepd. from one another based upon differences in electrochem. characteristics of the different nano- onions.