Recently I tried to synthesize carbon nanoparticles by nitric acid oxidation method (3 samples based on different starting material). I observed peaks at 1065 1383 1597 cm-1 for sample 1. 1066, 1351, 1591 cm-1 for sample 2 and 1066, 1343 and 1592 cm-1 for the third sample. I would like to know if my peaks match with graphitic peaks. I am confused.
It appears that the graphite you used contains significant concentration of chemical defects. Pure graphite has a single Raman line at 1370 cm-1 which is generally termed as G-band. You then observed another band near 1383 cm-1. This band is usually inactive for perfectly symmetric graphitic structure, but as soon as defect is introduced, the local symmetry is broken and becomes active. Therefore, in the very original Tuinstra & Koenig's paper in 1970, this more was coined as D-band (defect band). Frequency of the G and D-bands shift slightly depending on the concentration of the defects, as well as stacking structure including the number of grapheme layers. What you should have mentioned is one more band around 2730 cm-1, which is widely believed to be the overtone of D-band. The frequency, intensity and shape of this 2D band (some call it D* band) also gives you important information on the defect level and stacking structure of grapheme layers.
Sir, i did not observe any peaks in the 2730 cm-1 region. While analyzing XRD data, we observed a mixture of phases. which did not show any peaks corresponding to carbon based materials. I tried using the software called 'match'. It showed that my peaks had close relation to NaNO3 peaks. I would like to know what could be the possible reason.
Now you are talking about subject unrelated to Raman analysis of graphite. If you did not observe a line near 2730 cm-1, either the peak in this area was so low to observe (which is rather unlikely) or your sample is so glassy carbon. If the latter, your G-band should not be sharp either.
Regarding the Na NO3, when you treat your material, you must have neutralized the nitric acid with NaOH and formed a salt. Then, you tried to purify the final product. Could it be possible that you collected wrong product, the salt, rather than the carbon material you were after? If that is the case, it is very simple to verify by taking IR spectrum of the compound as carbon hardly show strong absorption, but NaNO3 does.
I was flipping through an issue of Spectroscopy and found this, it may be of help.
http://www.spectroscopyonline.com/carbon-black-line-characterization-using-portable-raman-spectroscopy
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