Please find the attached figure and paper
Why when we doped Yb broad peak is coming not intense peaks are coming which sites Yb is going to occupied it size is too bigger as compare to tiania Yb3+ is 86 pm and Ti4+ is 74 pm. What kind of geometry be possible for Yb3+ ion if it is in lattice postion.
The broad maximum corresponds to the amorphous material. It appears due to the synthetic route, not doping.
As for the Yb position, the authors do not show enough proof that Yb really enters the lattice, even though the enhancement of the photocatalytic properties probably means that some degree of doping really exists. The difference of the radii is really large, but not completely forbidding the minor doping. Similar to the famous YSZ, substitution of Ti by Yb will lead to the formation of the oxygen vacations which will partially compensate the strains caused by the large Yb ions.
Dear Alexenadar B. Missyul Sir,
As you said it is correct broad peak due to amorphous material but even they are heating at 500 degree so definetly TiO2 should formed by any synthetic route but why no peak is coming for anatase. How can we distinguish can raman spectra will help or any other spectroscopy technique help to us to know where we can find it.
Can we find out the percentage of dopant?
Again, there is not enough information about the experimental procedure. Crystallization takes time, so it is impossible to be sure that undoped TiO2 would crystallize at the same conditions. Anyway, Yb might affect the crystallization rate, why not?
In order to get information about the coordination of Yb, I would do XAFS. Look for example for much more careful description of the Sc-doped titania in J. Phys. Chem. C, 2013, 117 (48), pp 25276–25289. Also, longer annealing might make the minor Yb-containing phases visible by XRD. At the powder pattern shown at the figure that you attached even 10% impurity could remain hidden in the background.
You could also investigate the degree of crystallisation by electron diffraction and use TEM to find out where the Yb actually goes. We did this recently for Tb doped AlN and published the results in Appl. Phys. Lett. last year.
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