Catalytic Oxidation of NO over La0.8Sr0.2MnO3 Perovskite

Abstract

Catalytic oxidation of NO by O₂ over La_0.8Sr_0.2MnO₃ was tested in a tubular reactor. The reaction temperature ranged from 373 to 473 K, space time from 0.090 to 0.720 s, inlet NO concentration from 300 to 2000 μL/L, and O₂ volume fraction from 3% to 9%. The steady-state conversion of NO was increased significantly with increasing reaction temperature and the space time, slightly with increasing the O₂ concentration but decreased with increasing the inlet NO concentration at a lower temperature. Under the conditions of 0.720 s space time, 500 μL/L NO concentration, 5% O₂ volume fraction and 473 K, NO conversion reached 90%. A kinetic model including a network of 12 elementary reactions with the desorption of NO₂ as the rate-limiting step is established and fits the experimental data well. The activation energy of NO₂ desorption from the catalyst surface is determined to be 101 kJ/mol.