Motahare Haghighatjoo

Check for Zn(OH)2 and other impurities. At what temperature did you calcine your system?

Motahare Haghighatjoo I agree with Alan F Rawle , I've found it helpful to look for peaks corresponding to the precursors and the substrate layers. Did you check for different Phases of ZnO? If the nanoparticle film is thin you can try doing XRD at a shallower angle (GIXRD) this can help remove substrate peaks.

In such cases, my boss used to say: "Where are we going to mark peaks?"

There is not much ZnO here ... it is wiser to start over in full accordance with handbook.

Seriously though, there should not be so many peaks in the nanostate. This is most likely dirt, or improper placement of the sample in the XRD equipment.

Alan F Rawle

Thanks for your response.

At 40 degrees Celcius (after synthesis, I dried it overnight in an oven at 40 °C).

Motahare Haghighatjoo

You can't form ZnO at such a low temperature. Look at the TGA's and DSC's for this chemistry. For diagnosis, take a small amount of your material and heat to 4500 C . Then repeat the XRD and see what you get.

Alan F Rawle

Thanks for your advice. But I'm applying the biological methods, which means the enzymes play an essential role in nanoparticle production. I'm afraid heating up to 450 C could deactivate the bacterial enzyme.

Motahare Haghighatjoo

The test is diagnostic. Yes, you’ll degrade the organic matter - that’s not the point. You should get far fewer peaks synonymous with ZnO, IMHO.

Motahare Haghighatjoo Once you synthesize nanoparticles, do you still need the enzymes? You should calcinate nanoparticles at 450 oC as suggested by Professor Alan F Rawle

Sintering at high temperatures will also reduce the amorphous content.

Dear Motahare Haghighatjoo I fully agree with the excellent previous answers provided by Alan F Rawle, Vadim S. Gorshkov and Aarif Shah. You cannot convert the intermediate Zn(OH)2 to ZnO nanoparticles at temperatures as low as 40 °C. In my opinion it's impossible to produce pure ZnO and simultaneously keep the bacterial enzyme in your sample. After all the final goal is making pure ZnO NPs, right? My suggestion would be to check other references about synthesis of ZnO nanoparticles. The "Publications" section of RG is full of them. Simply search for a term like "green synthesis of ZnO nanoparticles" and then click on "Publications". This will provide you with a long list of relevant literature references about this topic. Many of them are even freely available as public full texts:

https://www.researchgate.net/search.Search.html?type=publication&query=green%20synthesis%20of%20ZnO%20nanoparticles

Just check any of these article like this one:

Green Synthesis of ZnO Nanoparticles and Its Application as nano-fertilizers

Article Green Synthesis of ZnO Nanoparticles and Its Application as ...

You will soon find out that the synthetic route normally requires a final calcination step at 450 or 500 °C.

Good luck with your work and best wishes!

Frank T. Edelmann

Thanks professor Edelmann. I will follow your sugestion.

Alan F Rawle

Thanks dear professor Rawle. I find your advice really helpful

The extra peak other than the peaks corresponding to ZnO clearly indicates the existence of materials having other phases. It might be due to improper formation of ZnO or improper handling during its characterization. You can repeat the characterization again and if you get the same results then definitely ZnO has not been synthesized properly and material is full of impurities.

Motahare Haghighatjoo This clearly indicates that sample synthesized is not ZnO for the simple reason that peaks are not uniform and intensity distribution of these peaks are not according to the one reported in paper. Pls repeat the experiment once more with proper steps. Whenever you want to confirm the XRD pattern, in addition to verifying from papers you can also go for JCPDS files for the respective nanomaterial.

Yogesh Kumar thank you. it was helpful

Motahare Haghighatjoo your most welcome

Hi Motahare Haghighatjoo

I think it is better to use strong software to find your sample phases.

I suggest X'pert highscore plus.

If you want I can help you.

Send me your material raw xrd file and tell me your material elements and fabrication process.

[email protected]

With best regards

Motahare Haghighatjoo, The peaks which lies at less than 25 degree of 2 theta angle are basically anharmonic thermal vibrations of ZnO and some peaks may arise due to zinc hydroxides ions and impurities.