Effects of Added CO2 and H2 on the Direct Decomposition of NO over BaMnO3-Based Perovskite Oxide

• Published in: Bulletin of the Chemical Society of Japan Vol. 81; no. 9; pp. 1175 - 1182
• Main Authors: Iwakuni, Hideharu, Shinmyou, Yusuke, Yano, Hiroaki, Goto, Kazuya, Matsumoto, Hiroshige, Ishihara, Tatsumi
• Format: Journal Article
• Language: English
• Published: Tokyo The Chemical Society of Japan 15.09.2008; Chemical Society of Japan
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.81.1175

N2 yield on Ba0.8La0.2Mn0.8Mg0.2O3 decreased from 70% to 30% on the addition of 1% CO2, which is a much larger negative effect than that seen with O2. The CO2 negative effects are not permanent and this may result from the inhibition of NO adsorption. Co-feeding of H2 as a reductant is effective for increasing NO conversion. This suggests that the catalyst surface was covered with strongly adsorbed nitrate or nitride species which formed by adsorption of NO on oxygen formed by the decomposition of NO, and the removal of this surface species might be the most important step for the NO decomposition reaction. Co-feeding of H2 is also effective for increasing the NO decomposition activity in the presence of CO2. The reaction mechanism was studied by IR measurements which also revealed that the surface of the catalyst was covered with strongly bound nitrate species (NO3−). The addition of H2 to the reaction mixture is effective for NO3− removal and so accelerates the NO decomposition under coexistence of CO2.