I have some samples of CuO nanoparticles, but I need to know the correct procedure to analyze the sample on the FTIR-ATR instrument. Also, what range should I expect my peaks to be visible in? 4000 cm−1 to 400 cm−1 or is it less than that?
I have read about KBr pelleting for the sample preparation, but can the analysis be done without it or is there any other way?
For the reference of my instrument, I have Perkin Elmer Spectrum Two.
I think you should be able to use your particles in principle directly. However, a bigger problem will be that CuO absorbs in the range between 150 - 600 cm-1(cf. Article Employing spectra of polycrystalline materials for the verif...
). Therefore, I would embed the particles into CsI and measure transmittance.
In ATR mode you can measure the nanoparticles without the addition of KBr. However, the classical range of 4000-400 cm-1 for the organic compounds is not suitable for CuO, but you must use an instrument measuring also under 600 cm-1, because the main absorption of CuO can be expected at about 500 cm-1.
Thomas Mayerhöfer Yes, I am concerned about that. I will try with Csl once. Thank you for this suggestion!!!
Marcella Bini I tried it once without KBr and as you said, there were literally no measurements beyond 500 cm-1. But even below 500-1, the result was not satisfactory.
I am attaching the obtained spectrum for your reference.
the spectrum is very strange...too many peaks...are you sure to have only CuO in your sample?
Marcella Bini Exactly, I had the same doubt looking at this result. I have been provided with this sample as a control for CuO NP (supposed to be pure), which made me doubt my procedure. So I believe it must be impurities in the sample itself.
It is not only that there are too many peaks, but also their halfwidth is much too small. Which equipment did you use? I am more at home in theory, but AFAIK ATR systems that allow to measure the FIR spectral region are rare and I never could test one myself...
In fact, as Thomas said, with ATR I usually measure only up to about 650, 600 cm-1 not more down. And in fact also the FWHM of peaks is also strange..do you have standard sample to measure, to verify if some experimental problem could be present?
Normal Cu - O fingerprint region is between 400-600.
- Kindly go through 10.1080/03602559.2017.1410832
Ananth Steephen Thank you for sharing this!
Ilham Ben Amor Ok. That might be the reason I am observing the peaks below 400 cm-1.
Thomas Mayerhöfer Marcella Bini I am using Perkin Elmer Spectrum Two ATR which I believe doesn't do well at FIR, it's best to be used at MIR.
But,
Article Synthesis, Characterization, and Antibacterial Activity of P...
Article CuO Nanorods: A potential and Efficient Adsorbent in Water P...
Article Bioelectrode based chitosan-nano copper oxide for applicatio...
these references showed the FTIR spectrum of CuO nanoparticles in MIR region. That made me wondered, what's the issue.
Marcella Bini I dont have any other standard CuO sample, infact the sample provided to me, of which the spectrum you see, is being claimed to be standard. I am starting to believe that there must be some error during the NP synthesis procedure.
Vivek Parab This explains your strange spectrum below 350 cm-1, since your spectrometer does not work below 350 cm-1. If your ATR equipment uses a diamond crystal than you might still be able to see the most intense CuO-peaks which you find according to Article CuO Nanorods: A potential and Efficient Adsorbent in Water P...
at 523 and 602 cm-1 if you use the KBr technique. Those peaks will be redshifted if you use the ATR technique and you have to correct this shift if you want to compare peak positions.
Thomas Mayerhöfer Great, that clears most of the queries. Any suggestions about how to correct the redshift? Haven't done that before.
Vivek Parab To a good degree the correction is possible with a program that many vendors add to their ATR accessories. It is usually called something like "Advanced ATR correction". Some more details you can find in the thread https://www.researchgate.net/post/ATR-correction-why-would-you-not-use-it
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