Plasma-Driven Water Assisted CO2 Methanation

By the application of pulsed corona discharges in a carbon dioxide atmosphere over a water film, the formation of methane has been observed under mild reaction conditions, without the application of a dedicated catalyst. Methane is proposed to result from hydrogenation of carbon monoxide and possibly also carbon dioxide at the NiCr alloy high-voltage electrodes, the precursors being formed by plasma-induced decomposition of carbon dioxide and water. Applying energy densities up to 46 kJ/L has yielded methane levels of approximately 440 ppm at a production efficiency of 398 pmol/J. The observed plasma chemistry occurs at ambient pressure, while gas phase heat is cooled away by the water film, the latter being thermally nearly unaffected.