화학공학소재연구정보센터
Catalysis Today, Vol.231, 155-163, 2014
Effect of Mg/A1 ratios on the NOx storage activity over Pt-BaO/Mg-Al mixed oxides
This study provides information on the optimal Mg/A1 ratio to use Mg-Al mixed oxide as a support for NSR (NOx storage-reduction) catalysis. When Pt and Ba were loaded, Mg-Al mixed oxide support showed superior NOx storage performance compared with gamma-Al203 supported catalyst, especially when Mg/A1 ratio ranges from 2:8 to 4:6. In addition to the intrinsic superior activity of the fresh catalysts, we confirmed the positive effects of containing Mg in thermally aged catalysts, such as better thermal durability due to the minimized Pt sintering and less crystalline BaAl2O4 phase formation, thus demonstrating better overall NOx storage activity. In particular, among the catalysts with various Mg/A1 ratios, Pt-BaO/Mg-Al mixed oxide support with the Mg/A1 ratio of 4:6 showed the highest NOx storage performance after thermal treatment at 800 C. However, the additional Mg loading to the support (Mg/Al 5:5) gave rise to the drastic decrease in the NOx storage activity and the poor thermal stability. Combined activity measurements and the physicochemical characterization results lead us to the conclusion that the use of optimized Mg-Al mixed oxide support can aid in improving NOx storage activity and preventing thermal deterioration.(C) 2014 Elsevier B.V. All rights reserved.