Abstract:

X-ray photoelectron spectroscopy (XPS) analysis was used to investigate effects of catalyst on soot oxidation characteristics, existing form and differences of soot and partially oxidized soot were examined. Printex-U (PU) was used to surrogate engine soot, soot became more and more ordered crystalline structure with the temperature increasing with no catalyst added. Soot added catalyst appeared similar oxidation mechanism as well as the microstructure with finish oxidation at 650 ℃ . However, soot appeared lesser ordered crystalline structure under high oxidation temperature of 1000 ℃ . The results show that Si-Al catalyst changes the soot oxidation mechanism under oxygen atmosphere, catalyst with finish oxidation at 1 000 ℃ promotes oxidation of ordered crystalline structure which was difficult to be oxidized.

Key words: diesel engine, particulate matter (PM) emission, soot oxidation, X-ray photoelectron spectroscopy (XPS), microstructure, catalyst