Low-temperature NO decomposition through microwave catalysis on BaMnO3-based catalysts under excess oxygen: Effect of A-site substitution by Ca, K and La

The low-temperature NO decomposition with high efficiency remains a grand challenge. Herein, we report an attractive approach for the low-temperature NO decomposition by microwave catalysis over BaMnO3 and substituted Ba(0.8)A(0.2)MnO(3) (A=Ca, K, La) catalysts. Importantly, impressively high NO conversion and N-2 selectivity with 99.9% and 99.9%, respectively, were achieved over Ba(0.8)A(0.2)MnO(3) catalyst at 250 degrees C. Comparatively, under identical conditions in the conventional reaction mode, the highest NO conversion and N-2 yield are respectively only 45.4% and 28.7% for Ba(0.8)A(0.2)MnO(3) at 650 degrees C. Unexpectedly, the effect of Ca, K and La substitution is different in these two reaction modes. The catalysts were characterized by H-2-TPR, O-2-TPD, and microwave absorbing properties to illustrate possible reasons causing such obvious differences in catalytic performance. The apparent activation energies for BaMnO3, Ba(0.8)A(0.2)MnO(3), Ba0.8K0.2MnO3 and Ba0.8La0.2MnO3 catalysts under microwave irradiation drop down to as low as 33.4, 41.6, 14.7 and 18.2 kJ/mol, separately, suggesting a significant microwave catalytic effect. (C) 2017 Elsevier B.V. All rights reserved.