After precipitating metal nanoparticles from their colloidal solution and drying them in an oven or in open air, part of these nanoparticles are converted to the corresponding oxide. The XRD shows the presence of metal oxide nanoparticles.
Thank you Hany. But I do not have this tube furnace. I try to find one arround. Do you have any idea about its price?
I dnt know about the solvent but if you are using water then you can go for freeze drying using liquid nitrogen (lyophilisation )
An important thing to keep in mind is the reactivity of the metal you have. Pt or Pd NPs are very stable toward oxidation and can be dried with out oxidation if they are supported on carbon. Otherwise, more active metal nanoparticles such as Ni could be dried under nitrogen or argon and then stored in a glove box to prevent oxidation during storage. For Ni NP in ethanol, we have dried them under argon using a schlenk setup and transferred them to a vial for storage in a glove box.
Thanks Christopher Koenigsmann. I am currentry dealing with Ag and Cu NPs. They are readly oxidized during drying specially if high temperatures are used. drying Ag NPs at 30oC should lower AgO than those dried at 70. The schlenk line suggest by
Jan Schröder and by you is very good idea however I have not tried it yet.
If you are synthesizing these nanoparticles, you can use a capping agent such as oleic acid. That would prevent the particles from oxidation.
You should be able to dry the Ag NPs under argon for instance but the Cu may require a reducing atmosphere such as hydrostar (5% H2 in Argon) to prevent oxidation. Using a reducing atmosphere may actually help to crystallize and remove amorphous deposits in the Cu particle sample.
To: Saad Khan Thanks for your answer. I am already using a capping agent.
dr. Manal el-sheikh, would you please tell me what is your capping agent? since, i want to anneal InSb layer without risking oxidation.
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