Overcoming Discharge Inhibition in n-Butane Oxidation: Two-Component BaTiO3 and Mn-Cu Mixed Oxide Coatings

A twin surface dielectric barrier discharge on the microsecond scale was used in combination with a two-component coating to oxidize 300 ppm n-butane as a model volatile organic compound to CO2 and H2O in synthetic air at room temperature and at 160 {\deg}C. The integration of BaTiO3 as a base material for the coating allowed the successful use of otherwise discharge-ignition-inhibiting materials such as MnO2-CuO applied as a full coating. Application of pure BaTiO3 led to highly porous coatings that do not hinder the discharge ignition and show a negligible influence on n-butane conversion while reducing byproduct formation. Thus, BaTiO3 was identified as a suitable structure-directing agent in two-component coatings, using 1:1 and 1:2 ratios of BaTiO3:catalyst coatings. Coated electrode configurations were compared to their respective uncoated state to highlight the coating-induced changes. The two-component coatings strongly increased the CO2 selectivity, reaching a maximum of 91.6 % at an energy density of 450 J/L and 160 {\deg}C for the 1:2 ratio, corresponding to an increase of 51.0 % relative to the uncoated electrode.