[Zurück]

J. Ofner, H. Grothe:
"A mechanistic study of the cooperative effect of NO2 and O2 on the soot surfaces";
Asian Chemistry Letters, 11 (2007), 1&2; S. 57 - 61.

Soot particles are emitted by Diesel engines and can be respired by the human lungs due to their small particle sizes. Particle filters, exhaust-gas recirculation systems and fuel additives are used to remove these particles from the exhaust gas stream. A low-maintenance possibility to avoid soot emissions are so-called continuous regenerating traps (CRT). In CRTs soot particles are oxidized to CO2 by the aid of the oxygen-containing exhaust gas constituents, i.e. NO2, O2 and H2O. Recent publications mention a cooperative effect between NO2 and O2 in the heterogeneous reaction on the soot surface. In the present study, we have applied temperature programmed oxidation (TPO-MS), temperature programmed desorption mass-spectroscopy (TPD-MS) and diffuse-reflectance-infrared-Fourier-transform-spectroscopy (DRIFTS) in order to investigate this effect in more detail. As a result new functional groups containing nitrates have been assigned on the soot surface, which were not detected within the reactions of the single gas components.