An apparatus for forming nano-structures of carbon solids includes a reactor chamber into which extends a plasma torch configured to generate a plasma plume that extends into the interior of the reactor chamber. CO2 from is applied to the plasma plume where the CO2 is dissociated into carbon and oxygen. A plurality of nozzles also extends into the reactor chamber, which sprays liquid water on the plume, cooling at least a portion of the carbon causing it to form solid carbon nano-structures in a mixture of liquid water. The mixture is conveyed to a flocculation tank.