NO oxidation performance and kinetics analysis of BaMO3 (M=Mn, Co) perovskite catalysts.

Abstract

Perovskite is an efficient and emerging catalyst for NO oxidation. In this study, BaMnO3 and BaCoO3 perovskite catalysts were synthesized by the sol-gel method, and their catalytic oxidation performances of NO were studied. The catalytic performances indicated that BaMnO3 and BaCoO3 perovskites had the highest NO oxidation activities with the NO conversions of 78.2% at 350°C and 84.3% at 310°C, respectively. The high activities of BaMnO3 and BaCoO3 perovskite catalysts were related to the abundant surface adsorption oxygen (OA = 76.21% and 78.57%, respectively) and the high concentration of Mn4+ (Mn4+/Mn = 66.95%) and Co3+ (Co3+/Co = 63.8%). Moreover, the results of FT-IR and kinetics revealed that NO and O2 adsorbed on the surface of samples and combined with the B-O band to form bidentate nitrate and bridging nitrate, which eventually was converted into NO2. The kinetics analysis revealed that the NO oxidation reaction followed the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. In addition, the activation energies were 36.453kJ/mol for BaMnO3 and 30.081kJ/mol for BaCoO3, implying that BaMnO3 and BaCoO3 provide low-cost and efficient catalysts, which can be comparable to Pt noble metal catalysts.