A system and process for producing doped carbon nanomaterials is disclosed. A carbonate electrolyte including a doping component is provided during the electrolysis between an anode and a cathode immersed in carbonate electrolyte contained in a cell. The carbonate electrolyte is heated to a molten state. An electrical current is applied to the anode, and cathode, to the molten carbonate electrolyte disposed between the anode and cathode. A morphology element maximizes carbon nanotubes, versus graphene versus carbon nano-onion versus hollow carbon nano-sphere nanomaterial product. The resulting carbon nanomaterial growth is collected from the cathode of the cell.