Ionically conducting ceramics for soot oxidation. Mechanistic study with O-18(2) isotopic exchange
Résumé
This study shows that Yttria-Stabilized Zirconia (YSZ) is an effective catalyst for soot particles oxidation. Soot oxidation already occurs from 270 degrees C. Temperature-Programmed Oxidation experiments with O-18(2) demonstrate the key-role of bulk oxygen species in the oxidation process. To the best of our knowledge, this is the first time that such a result is reported for a purely O-2-ionically conducting ceramic without any redox property. We assume that the soot oxidation takes place via a fuel-cell type electrochemical mechanism at the nanometric scale. Electrochemical oxidation of the soot takes place at the soot/YSZ interface while oxygen electrochemical reaction occurs at the triple phase boundary.