My TiO2 powder is showing anatase, rutile and brookite phases as evidenced from XRD. Using OriginLab, I did signal processing (smooth-75pts) and then integrated the peak area under Anatase (101), Rutile (110) and Brookite (121) to calculate the respective phase percentage using the equations:
Wa=KaAa/(KaAa+KbAb+Kr)
Wb=KbAb/(KaAa+KbAb+Kr)
Wr=Ar/(KaAa+KbAb+Kr)
where Wa,Wb and Wr= weight fraction of anatase, brookite and rutile phases.
Aa,Ab and Ar-are the respective integrated intensities
Ka= 0.886; Kb= 2.721
As per my calculation; Anatase = 60%; Rutile =13% and brookite=27%. Kindly help me to cross check my calculation. If it is wrong, Please let me know the correct way to calculate it.
excel sheet and the XRD pattern is attached herewith.
Thank You!
Please check Rietveld Analysis or Data Fitting Methods/ Voigt Method for the Analysis of XRD data. Generally companies providing XRD Tools are equipped with such Analysis Tools.
I want to add some critical points to above answer given by Mr. Naveed:
First of all if u want to generate the pure of Titania Phase, pls try to see the effect of temperature during the calcination process(ie during the annealing process). Along with that your sample shows high amount of amorphous behavior. That is very bad practice for any application (provided u r using chemical route to synthesis it). And your X ray analysis is not properly done. Try to use some analysis tools like Xpert high score for analyzing of your samples. Because FWHM of your XRD peaks of your sample are large. Along with that you can look for ward towards Auger electron spectroscopy for phase volume quantification.
The integrated intensity of Bragg reflections scale with the structure factor of the crystallographic compound. Various other factors like the volume of crystallographic unit cells, density of the different compounds and their x-ray absorption coefficient also have to be considered. In addition, you have to be sure that the grains you are analysing by observing those particular hkl reflections exhibits no preferred orientation (texture). The thorough analysis of phase mixtures is explained in the second chapter “Identification of chemical phases” of the book “Thin-film analysis by x-ray scattering”. You have to apply formula (2.13) to your problem. I think it is always better for a researcher to understand and apply the basic formula than simply using coefficients, about the correctness of which you are not fully aware.
Book Thin Film Analysis by X-ray Scattering
@ Mr. Rahul Kumar- I have synthesized it via chemical route. The larger FWHM can be due to smaller crystallite size as well. Nanoparticles always have higher FWHM. Can you please be specific about the X-ray analysis not being done properly? Thank you for your suggestions!!
@ Mr. Mario Birkholz- Thank you for your valuable suggestions. The equations that I have mentioned for the calculation of different phases has been extensively cited in literature. I will further read to understand better.
Some common points of error in your analysis are:
Usually in your analysis, base line correction is not done properly. Along with that, most of your peaks r very broad(more the allowed limit), still how u can correctly quantify your peak. Above all, in some case or in general mostly when we do analysis through Software like X pert highscore, the identification done by the software is not always accurate especially in your case. I think most of your peaks shows overlapping of various phases. There u have to take care very carefully. Bcoz even analysis through software also have detection and resolution limit. For better quantification, we have to look forward to other analysis tools.
And regarding synthesis method i think u used is sol gel approach for the synthesis. But the main motive of using any chemical approach is to generate nanomaterial of narrow size range and uniform morphology. And i think you have used sol gel approach. If u want to generate nano-material of good quality (better shape and size), look for towards thermal decompostion at high temperature. Bcoz there u can control and tune process like nucleation, oswald ripening etc. and hence u will definitely generate better nanoparticle.
@ Mr. Rahul Kumar- Thank you for your valuable suggestions. Yes, you are right , the analysis has been done using Xpert highscore software. Can you please give some tips for doing peak analysis using the Xpert software. (You have mentioned about baseline, detection and resolution limit). What other analysis tools do you suggest?
And can you please explain the allowed limit for broadness of the peaks.
Thank You!
@ Mr. Rahul Kumar- Thank you for your valuable suggestions. Yes, you are right , the analysis has been done using Xpert highscore software. Can you please give some tips for doing peak analysis using the Xpert software. (You have mentioned about baseline, detection and resolution limit). What other analysis tools do you suggest?
And can you please explain the allowed limit for broadness of the peaks.
Thank You!
@ Mr. Rahul Kumar- Thank you for your valuable suggestions. Yes, you are right , the analysis has been done using Xpert highscore software. Can you please give some tips for doing peak analysis using the Xpert software. (You have mentioned about baseline, detection and resolution limit). What other analysis tools do you suggest?
And can you please explain the allowed limit for broadness of the peaks.
Thank You!
There is an alternative method to find out the volume percentage of different phases present together. For the calculation of the same, firstly, you have to identify the maximum intense peak of the phase present in the XRD pattern then find out the area under the peak for each. Then using the following formula, you can estimate phase fraction present in the sample.
Formula: phase fraction of 1st phase f1 = A1/(A1+A2+A3+...) and so on.
or f1 = I1/ (I1+I2+I3+...) and so on, where I, is intensity of most intense peak.
Refer the attachment (instead of cubic JCPDS you can use data of Anatase, like wise you can compare other structures.)
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