Reduction of nitrogen oxide by steam electrolysis cell using a protonic conductor SrZr sub(0.9)Yb sub(0.1)O sub(3- alpha ) and the catalyst Sr/Al sub(2)O sub(3)

• Published in: Solid state ionics Vol. 134; no. 3-4; pp. 241 - 247
• Main Authors: Kobayashi, Tetsuro, Abe, Katsushi, Ukyo, Yoshio, Iwahara, Hiroyasu
• Format: Journal Article
• Language: English
• Published: 01.10.2000
• ISSN: 0167-2738

A steam electrolysis cell was constructed with a high-temperature type protonic conductor, SrZr sub(0.9)Yb sub(0.1)O sub(3- alpha ). The reduction of nitrogen oxide (NO) by hydrogen, which was produced by a steam electrolysis cell, was examined. Helium gas with 8% O sub(2) and 1000 ppm NO was used as a model gas for the exhaust gas from automotive engines operating under lean-burn condition. The removal efficiency of NO was measured, using steam electrolysis cells with different catalysts on the cathodes. A mixture of Pt-sponge and Sr/Al sub(2)O sub(3) catalyst was found to be most effective for the preferred reduction of NO in the presence of excess O sub(2). It was suggested that the preferred reduction of NO occurred via the electrochemical reduction of NO absorbed into Sr/Al sub(2)O sub(3), not via the chemical reduction of NO by H sub(2) gas.