Electrolysis methods that utilize carbon dioxide and a non-iron additive for making desired nanocarbon allotropes

A method for producing a carbon nanomaterial (CNM) product, the method comprising steps of:

• (a) heating an electrolyte media to obtain a molten electrolyte media;
• (b) positioning the molten electrolyte media between an anode and a cathode of an electrolyte cell;
• (c) introducing a source of carbon into the electrolytic cell;
• (d) introducing an iron-free, nickel-free, chromium-containing additive into the electrolyte media before the step of heating or introducing the iron-free, nickel-free chromium-containing additive into the molten electrolyte media, wherein the iron-free, nickel-free, chromium-containing additive is added in an amount of between 0.05 wt % and 2 wt %, relative to the amount of electrolyte media or the molten electrolyte media;
• (e) applying an electrical current to the cathode and the anode in the electrolytic cell;
• and
• (f) collecting the CNM product from the cathode, wherein the CNM product comprises a minimum relative-amount of between 50 wt % and 99 wt %, relative to a total weight of the CNM product of nano-carbon flowers, wherein the nano-carbon flowers each comprise multiple, frusto-conical carbon nanotubes that originates from a single point of origin.