The effect of the degree of soot crystalline structure on soot oxidative reactivity was studied for 5 soot samples using Raman spectroscopy, x-ray diffraction (XRD) and thermogravimetric analysis. For Raman spectroscopy, first-order Raman spectra ranged at 800-2000 cm-1 were curve-fitted with 3 peaks (D1:1360, G:1580 and D3:1360 cm-1), 4 peaks (D1, G, D3 and D4:1180 cm-1) and 5 peaks (D1, G, D2:1620 cm-1, D3 and D4), and D1 full width at half maximum (FWHM) and area ratio of D1 to G (ID1/IG) were used as Raman parameters. Overall, D1 FWHM and ID1/IG from 3 and 4 peaks show a good correlation with soot oxidative reactivity. When these Raman parameters were compared with crystallite size from XRD for a sample at different oxidation stages, D1 FWHM appears to be a better parameter showing increasing crystalline order. Therefore, Raman parameter is shown to be a powerful tool to determine soot crystalline structure.

Raman spectroscopy for the study of soot crystalline structure and soot oxidative reactivity

239th National Meeting (2010)

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