Plasma catalysis over lanthanum substituted perovskites

The removal of CH4 (3600 ppm) with O2 (3 × 104 ppm) in mixtures with Ar or N2 as carrier gas has been studied in a plasma-catalyst system. The plasma yields CO plus H2O as majority products. A small extra oxidation to CO2 is found at 338 K when a catalyst (SiO2 or La1−xSrxCoO3−d (x = 0.5) perovskite) is placed in the glow zone of the plasma. With the perovskite, the oxidation efficiency to CO2 increased with temperature up to 90% at 453 K. This result supports that this lanthanum substituted cobaltite further activates the plasma species producing a synergetic effect where the specific surface area is not a critical factor as previously reported in the literature.