Hydrogen production by a new selective partial oxidation of methane in air using reducted La0.5Sr0.5CoO3-delta as catalyst for fuel cell applications

摘要

Catalytic activity of the La0.5Sr0.5CoO3-delta perovskite (LSC) has been studied during the methane oxidation under air/hydrocarbon mixtures. Reactions were carried out in a quartz tube at atmospheric pressures, in the 500-880 degrees C range. Considerable changes in product selectivity were observed in function of temperature, partial gases pressure, total flux rates of the gas mixture and the reduction state of the cobaltite. A new reaction that produces the selective partial oxidation of methane giving mainly CO2 and H-2 as products has been identified using previously reduced cobaltites as catalyst. The optimal experimental conditions for reducing LSC cobaltites to obtain the selective partial oxidation of methane were found using appropriate methaneitrogen/oxygen mixtures. Annealing of the LSC under methane at low oxygen partial pressures respect to the natural air (20% O-2, 80% N-2) at relatively high temperatures produces the reduction of the cobaltite and consequently the selective partial oxidation of methane.