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Medium-temperature electrolysis of NO and CH4 under lean-burn conditions using ytrria-stabilized zirconia as a solid electrolyte

1995; Royal Society of Chemistry; Volume: 91; Issue: 13 Linguagem: Inglês

10.1039/ft9959101955

1364-5455

Takashi Hibino, Kenichi Ushiki, Yoshitaka Kuwahara, Misukuni Mizuno, A. Masegi, H. Iwahara,

Catalysis and Oxidation Reactions

Electrolysis of NO and CH4 in the presence of excess O2 has been studied using a single-compartment reactor, constructed from yttria-stabilized zirconia (YSZ), with two palladium electrodes. The palladium electrodes were attached by an electroless plating method. Experiments were conducted between 550 and 900 °C with a mixture of 1000 ppm NO, 1000 ppm CH4, 2% O2, 5% H2O and 5% CO2 in argon at a flow rate of 50 ml min–1. The reduction of NO to N2 and the oxidation of CH4 to CO2 were promoted by applying a direct current between the two palladium electrodes. The current efficiency for the reduction of NO was about 1.5% at all measured temperatures, while that for the oxidation of CH4 decreased from 2.7 to 0.3% with increasing temperature from 550 to 900 °C. The dc resistance of the reactor was mainly due to the ohmic resistance of the electrolyte. The transport properties of O2– through the electrolyte followed Faraday's law under operating conditions. These results were strongly dependent on the morphology and thickness of the palladium electrode.