Selective Oxidation of Methane to Methanol and Formaldehyde with Nitrous Oxide in a Dielectric-Barrier Discharge−Plasma Reactor

The partial oxidation of CH4 with N2O in Ar has been investigated at atmospheric pressure in a dielectric-barrier (silent) discharge plasma induced by low input power in a range from 0.27 to 7.71 Wh(Ncm3)-1. In an Ar stream, about 10% of the combined yield of CH3OH and HCHO and 40% of the selectivity to these products were achieved, with CO being the other major product. Low power favored selectivities to unstable partial oxidized products and supressed further decomposition to carbon oxides and carbonaceous deposits on the electrode surface. Kinetic and spectroscopic observations indicated that Ar carrier gas played an important role in the highly selective oxidation of CH4 to CH3OH and HCHO via energy transfer from excited-state Ar species to the reactant molecules under the mild conditions examined.