Study on the Reaction Mechanism for Soot Oxidation Over TiO2 or ZrO2-supported Vanadium Oxide Catalysts by Means of In-situ UV-Raman.

The reaction mechanisms for diesel soot oxidation over V4/ZrO2 or V4/TiO2 oxide catalysts were studied by the means of in-situ UV-Raman spectroscopy. The results indicate that the formation of surface oxygen complexes (SOC) is a key step and the SOC species mainly exist as carboxyl groups. The presence of NO in the reaction gas stream can promote the formation of SOC species. For soot oxidation over V4/TiO2 catalyst, NO2 can be produced and remarkably accelerate soot oxidation. Based on the UV-Raman experimental results, two different reaction mechanisms are proposed for soot oxidation over V4/ZrO2 or V4/TiO2 samples, respectively. [ABSTRACT FROM AUTHOR]