I loaded Ag onto TiO2 by photodeposition method. this is the XPS figure for Ag3d. as we can see, the first peak split on the top, and the second peak is relatively flat.are they overlapping peaks? I mean whether this figure can obviously tell that there are two different Ag species in the samples. please look at the figure1.
Dear Xu,
There are several points to consider here:
1- (Assuming that this is binding energy on the x-axis) I am not aware of any Ag 3d5/2 peak maximum at such high BE!! Usually, it is between 367-369 eV, but you have 372 eV. It implies a possibility of very strong charging of your surface. Is your sample well grounded? did you measure multiple scans and no shift was observed?
2- Regarding the two tiny ~peaks (noise) you see for the 3/2 peak maximum; XPS data are better seen as scatter of points with a lorentzian gaussian fit. A line plot of the raw data makes the noise looks like peaks. (Similarly, you do not assume the background noise as peaks!)
3- If you have two species of Ag, then you will see it in both of the spin splits (3/2 & 5/2), It cannot be flat for one and not the other.
4- From your figure, you have a full width half maximum (FWHM) of about 2eV, it makes sense to expect having more than a species of Ag. However, this depends on many factors, such as, energy step and pass energy (PE) that were used to obtain this spectrum. if we assume that the pass energy that was is good enough to obtain high resolution spectrum, such as ~10eV (depends on the system capabilities) and step energy of ~0.05eV, then usually you get a FWHM of ~0.7 eV for elemental Ag and it goes up to 1 eV in case of AgO2. However, if you use a high PE such as 50 eV, then a substantial broadening can happen.
5- After careful consideration of the points before, comes the question of: did you do a survey scan covering all core levels? (a fast scan that tells you what elements you have in your film). If you detected other materials in the survey scan, then you can evaluate the possibility that it is bound to Ag and for sure it helps for better deconvolution of your spectrum.
I hope this will help you.
All the best
Zafer
The references below should help you determine the answer to your question. After you read the literature and complete some peak fitting analysis, let us know what you do not understand.
https://www.sciencedirect.com/science/article/abs/pii/036820489185008H
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Article A new anode material of silver photo-deposition on TiO2 in DSSC
Dear Xu,
There are several points to consider here:
1- (Assuming that this is binding energy on the x-axis) I am not aware of any Ag 3d5/2 peak maximum at such high BE!! Usually, it is between 367-369 eV, but you have 372 eV. It implies a possibility of very strong charging of your surface. Is your sample well grounded? did you measure multiple scans and no shift was observed?
2- Regarding the two tiny ~peaks (noise) you see for the 3/2 peak maximum; XPS data are better seen as scatter of points with a lorentzian gaussian fit. A line plot of the raw data makes the noise looks like peaks. (Similarly, you do not assume the background noise as peaks!)
3- If you have two species of Ag, then you will see it in both of the spin splits (3/2 & 5/2), It cannot be flat for one and not the other.
4- From your figure, you have a full width half maximum (FWHM) of about 2eV, it makes sense to expect having more than a species of Ag. However, this depends on many factors, such as, energy step and pass energy (PE) that were used to obtain this spectrum. if we assume that the pass energy that was is good enough to obtain high resolution spectrum, such as ~10eV (depends on the system capabilities) and step energy of ~0.05eV, then usually you get a FWHM of ~0.7 eV for elemental Ag and it goes up to 1 eV in case of AgO2. However, if you use a high PE such as 50 eV, then a substantial broadening can happen.
5- After careful consideration of the points before, comes the question of: did you do a survey scan covering all core levels? (a fast scan that tells you what elements you have in your film). If you detected other materials in the survey scan, then you can evaluate the possibility that it is bound to Ag and for sure it helps for better deconvolution of your spectrum.
I hope this will help you.
All the best
Zafer
The splitting is due to oxygen bonding in the same material . Just oxidise your material see the XRD . The heat it in Hydrogen +Argon atmp see the difference you can realise the change in peaks splitting at different level
thank you very much, I will consider your suggesstion carefully. but a problem is the content of Ag in my catalyst is very little, just 0.5% mass ratio.@Dhananjeyan Manikka
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