During the synthesis of copper nano-particles (by chemical reduction of copper salt), UV-vis scanning spectra was obtained.
In the scan, the resonance peak is observed. SEM analysis confirms the formation of copper nanoparticles. But I can't determine either its copper nanoparticles or copper oxide nanoparticles.
dear kumar
from FTIR spectroscopy you know the copper nanoparticles or copper oxide nanoparticles.
I suggest you do XRD analysis. It typically requires no sample preparation and the result is dependable. I have often seen copper nanoparticles that also contain some copper oxide (mainly Cu2O) due to slight oxidation during preparation and/or storage. You might also be able to find/reference literatures that have characterized both of these particles using UV-Vis spectroscopy.
Dear Sir,
you can also use a microwave GHz reflection loss measurement for Cu nanoparticles at a thin film subtrate and the Substrate with Cu2 O nanoparticle.
Use a microwave networkanalyser a 50 ohm waveguide an a amplifier.
Yours Sincerely
Cu nanoparticles are Raman inactive and Cu2O nanoparticles are Raman active.. Hence, Raman spectroscopy will give characteristic peak for Cu2O and no peak for Cu. CuO is also raman active but it show peaks at different cm-1.
Be careful: your particles do have oxides, the question is how much of them. So Raman (incapable of detecting Cu) cannot give definitive results. XRD is also questionable - oxide layer on nanoparticles could be amorphous.
You have not stated how large (or small) they are and or crystalline. My 2 cents. Only TEM combined with diffraction can resolve the question you asked. Furthermore when the layer(s) becomes less than 2nm it's becoming extremely difficult to analyze the difference between Copper 1 and copper 2 oxide, because outside the (crystalline) core there is always an oxide layer.on top . Have a look at one of my papers about copper NPs.
By EELS (electron energy-loss spectroscopy) is straightforward to determine whether Cu is oxidized or not. From the fine structure in the copper L2,3 edges you can also know its oxidation state. If you do your experiment in STEMyou can also knows its spatial distribution.
the particle size of nanoparticles is about 100 nm as confirmed by SEM.
will the conversion of some amount of copper to copper oxide, will change the release of copper ions form the product. ?
how can i prevent the conversion of copper to copper oxide ?
XPS would be a reliable method to quantify the differences in elemental composition between your samples.
by using the UV-vis scanning spectra , you can determine the gap energy .
you can found ,in the literature , the gap energy value of the copper oxide nanoparticles.
by using near-FTIR SPECTRA , you can know if the copper oxide quantity grow up after the treatment or not
try chemichally dissolve Co-oxide, using acid like HCl, its cannot dissolve metalic Cu but can dissolve and remove from the system Co-oxide. and the ge spectra again.
I've had the same issue. XPS is only partially helpful as it does not clearly distinguish Cu(I). It can differentiate between Cu(0) and Cu(II) well, but if you have precursor present or mixed oxidation states or Cu2O, you will still have questions. If the particles are large enough, XRD could give you good results. My particles are too small for XRD, so I ended up having to use HRTEM and carefully analyzing the lattice spacings for my samples. The spacings are sufficiently different that if you have enough resolution on the microscope, it's no problem to tell the difference. It is tedious though.
Do you have any idea how large the particles are? Given your UV-vis and the size, I would have a guess about the composition.
all methods told here are very useful for sure, however, here our friend got confirmed Cu by SEM (how SEM can show it's Cu or Cu oxide I did not get...), as far as I understand, oxide presents in trace amount, so here looking for oxide particle by XRD, TEM HRSEM is unpractical. XPS can show whether there is Cu-oxide or not, but if can not answer to question about UV-vis scanning spectra of oxide.
Copper nanoparticle (if well dispersed) has a very characteristic surface plasmonic band in the visible region with the wavelength about 550 nm or even longer. If you doubt your material is copper metal or oxides, just add some ammonia to the dispersion. Both Cu(I) and Cu(II) will dissolve right away, while metallic copper nanostructures can sustain hours. Also, XRD and TEM with the lattice info are very helpful, because the Cu oxides are usually well crystallized in aqueous solution or humid environment.
I met another problem.i did sputtering with cu metal in the presence of argon and oxygen. but i could not found cuO exactly by raman. my peaks are are at 245,550 and 1080. its not supported the previous literature.could some one guide me how to deal with this issue.i want to get CuO or Cu2O.
If you have access to a TEM you can try High resolution imaging and analyze the FFT of different particles.
If you have access to Electron energy loss spectroscopy you can try mapping of oxygen and also to measure the copper edge in different particles. The Copper edge of copper and copper oxides are VERY different. Then you can correlate the oxygen map with the copper edges (and eventually the FFT of the particles) and obtain a robust conclusion.
Good luck
i think that you n:eed to use many way:
xrd for size
xps for compound percentage
HRTEM for shape of particule
Perform XRD analysis along with EDAX...it should give you the elemental composition of your preparation...and then carry out HR-TEM/XPS.
in UV-Vis, for copper nanoparticle, u sld get a peak at around 560-600 nm. if ur nt getting then itis CuO/Cu2O.
from SEM u cant assure that it Cu or CuO...
copper nanoparticle peak is mostly be around 560-600 nm
copper oxide peaks are mostly be around
Cu2O at 542 nm, CuO at 310, and there is a peak for copper oxide nearly about 800 nm
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