Shape Controlled syntheis of Colloidal Platinum Nanoparticles (.PDF attachment) references that the inventors bubbled Argon Gas into the Potassium Chloroplantinate II solution for 20 minutes.
Are they doing this to Degassify the solution? I have included the document where the information came from and have highlighted it so it will be easy to find the details of the procedure.
Ar gas is passed to remove any dissolved oxygen present in the solution before the reduction process for Pt ions to be carried out.
Purging of the argon gas was done in order to prevent the further oxidation of platinum complex due to air and it also helps to prevent the agglomeration of platinum complex by increasing the surface area at the interface...
Dear Mahesh, the agglomeration procees is prevented by Sodium polyacrylate as stabiliser for nanometals and not by Argon gas
its an inert gas and so to keep the atmosphere of the reaction inert the gas is passed. If you perform the experiment in absence of Ar gas the nanopaprticles may form but the formation of impurities will be relatively higher.
Dr. Subramanium, Mahesh is partly right. It presence of Ar gas the nanoparticles will not be exposed to other gases thus preventing functionalization of nanoparticles. In presence of some gases the nanoparticlees can be automaticallly functionalised thus creating chances of agglomeration, however the chances of that is very low but still it can happen :-)
Actually the oxygen is to create the vacant in the linter layer growth on nano particle synthesis, it may prevent by argon gas addition, but still doubtable why they not recommend N2 gas.
Argon gas is inert in nature. Here it is mainly used for removing dissolved gases in the solution to provide a prospective atmosphere for growing platinum nanoparticles. Also it is heavier than air and it covers the solution surface as a blanket, so, it prevents the contact of air in the surface of solution during hydrogen gas bubbling.
The presence of oxidizing species in solution such as molecular oxygen, chloride, bromide etc. have been shown to selectively etch certain facets during the growth of noble metal nanoparticles especially Pd and Pt. This can lead to significant differences in morphology for example:
Synthesis of Ultrathin Palladium and Platinum Nanowires and a Study of Their Magnetic Properties
DOI: 10.1002/anie.200704707
Angew. Chem. Int. Ed. 2008, 47, 2055 - 2058
We have also shown the presence of oxygen can lead to the presence of residual oxide impurities in Pt nanostructures grown in solutions exposed to the air. (See cited article)
Collectively, these might be reasons to de-gas a solution before the growth of Pt nanostructures. Hope this is helpful.
Article Size-Dependent Enhancement of Electrocatalytic Performance i...
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