Hello everyone, I'm a student conducting research. I synthesized pure TiO2 NRs under the same conditions, with identical temperature and duration for calcination. The only difference lies in the hydrothermal time; the blue line was synthesized with the shortest duration, while the red line represents the longest. However, I observed a peak shift in the XRD results. Could it be due to crystallite size or is there something wrong with my sample?
Hello Srijitra Khanpakdee
A shift of the whole pattern is due to change in lattice parameters, according to Braggs' Equation. The green pattern shift to the left means that the unit cell is bigger than the one in blue. Feel free to reply if you need more help about this.
Sincerely
Ricardo Tadeu
Ricardo Tadeu Maia Thank you, sir. I synthesized TiO2 on FTO, and I also wonder why the FTO peaks have shifted too?
Dear Srijitra Khanpakdee ,
you dealt with two (three) different samples. Thus you may suffer from sample height misalignment in the XRD device. Sample height misalignments affect the positions of all peaks in the XRD pattern.
I assume that the positions of the FTO peaks will not be affected by the TiO2 layer. So there will be an experimental issue; do your FTO plates have the very same thicknesses*)?
Peak shifts due to sample height misalignments are discussed for example in:
Presentation XRD and XRR angular shifts due to sample height variations
*) please have for example a look at:
https://www.ossila.com/products/fto-glass-unpatterned
They announced a change of specification with respect to the FTO thickness by 0,1mm...
Best regards
G.M.
Dear Srijitra Khanpakdee ,
additional remark:
In the meanwhile I reflected about a procedure on how to distinguish the two cases of peak shifts caused by
a) a change of lattice constant (as suggested by Ricardo Tadeu Maia )
and
b) by a sample height misalignment.
I came up with the angular (theta) dependence of the peak shifts...
In case (a) there should be a tan(theta) dependence of the peak shifts
(see for example my recent presentation:Presentation XRD peak shifts due to change of lattice constant(s); is the...
)Due to those consideratios there should be an increase of peak shift for increasing theta which is stronger than theta (tan(theta) > theta)...
In case (b) there should be a cos(theta) dependence on the peak shifts (see for example my recent presentation: Presentation XRD and XRR angular shifts due to sample height variations
)Due to these consideration there should be a slight decrease of the absolute values of the peak shifts for increasing theta...
From your XRD pattern above you may judge yourself the theta dependence of your peak shifts...
From my point of view: slight decrease of peak shifts for increasing theta