▎ 摘　　要

NOVELTY - Production of a carbon material involves electrolytically reducing carbon dioxide to diamond in an electrolytic reduction system having an anode, a cathode, and an electrolytic solution (7) containing carbon dioxide and an ionic liquid. USE - Production of carbon material such as diamond, glassy carbon, amorphous carbon, carbon nanotubes, carbon nanohorns, and graphene used in environmental applications. ADVANTAGE - The method efficiently produces carbon material by reducing carbon dioxide at low cost. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for the electrolytic reduction system, which comprises the electrolytic solution containing ionic liquid which is chosen from imidazolium-based ionic liquids, aromatic-based ionic liquids, pyrrolidinium-based ionic liquids, ammonium-based ionic liquids, piperidinium-based ionic liquids, and quaternary phosphonium-based ionic liquids. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the electrolytic reduction device. 1Electrolytic cell 2Carbon dioxide supply tube 3Exhaust pipe 4Lead wire 7Electrolytic solution