An in-situ DRIFTS study in the reaction between NO x and soot on BaAl2O4

The interactions between NO, O₂ and their mixture on BaAl₂O₄, as well as the reaction of NO _x with soot in the presence of O₂, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). NO adsorption produces only nitrites species in the absence of O₂. NO₂ adsorption produces nitrates species besides nitrites species. The produced nitrites will further react with O₂, O_surf⁻ and O_lattice²⁻ to form nitrates. The reaction of NO _x with soot begins with the reaction of nitrates with soot oxygenated complex (C(O)), which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NO _x with soot in the presence of O₂. Supported by the National Natural Science Foundation of China (Grant No. 50506015), and Shanghai Rising-Star Program (Grant No. 06QA14027)