Synthesis of carbon nanotubes (CNTs) from only carbon dioxide was performed using hybrid reactor of dielectric barrier discharge and solid oxide electrolyser cell (SOEC). The removal of oxygen by SOEC from the plasma region suppresses the regeneration of CO2 from CO and complete CO2 conversion was achieved by the hybrid reactor. Co-Mo catalyst supported on a quartz substrate was inserted into the hybrid reactor and aligned CNTs were able to be synthesized on the substrate using only CO2 as a carbon source.