Carson Chu it is prominent peak. Suggestions:

a. think for the impurities maybe present in your sample.

b. repeat the XRD with a new sample.

Dear Carson Chu ,

you suppose 'noise' from the background.

But I think it is no noise from the back ground; noise does not show up as a broad peak. I it could be an XRD signal from your sample support/substrate.

In order to give an answer on that, I would ask you to answer some questions:

a) What sample support/substrate do you use, and

b) what is the estimated thickness or mass coverage of your soot sample.

And when repeating the experiment, as Syed Waqar Hasan suggested, please perform a scan without any soot, but with the substrate; so will have the net signal from your support/substrate. A peak around 60° may show up...

Good luck

Dear Carson Chu,

I agree with both answers.

Check for nitrogen-graphite, a usual interlayer flake compound, obtained by gas inclusion by diffusion mechanism. Knowing the local geological origin, helps the identification.

Impurities are always present in natural graphite samples, especially in larger flakes. Once particles are reduced, some times are easily visible at SEM. If possible, SEM with atomic number mapping will evidence those occurrences.

Best regards

WNM

What is about contamination with NiO?

See for example fig 1 of:

https://www.nature.com/articles/srep07413

You may perform XRF in addition to XRD.

Thanks, I would first check with the background with the technician.

Gerhard Martens I used silicon wafers. However, the soot was scrapped off for measurement. But, yea, it could be from the support. I need to ask my technician to perform a measurement without anything. We will see.

Wagner Da Nova Mussel the soot is from a C2H4 flame. So it is unlikely that the soot would contain any nitrigen content. However, it raises another question for nitrogen-fueled flames.

Gerhard Martens It turns out to be the background measurement with the empty silicon wafer. Thank you for your suggestion.