Dear all, please take a look at the attached files. My Regards

Saba Fatima

You need an appropriate metal precursor (depends on what colloidal metal you want; if it's metal you want - maybe you want another type of 'nanoparticle') plus the appropriate reducing agent(s) present in the plant extract. So, you need to be much more specific. Other factors that will need to be examined and are part of a method are concentrations, temperature, and pH, plus any additional chemistry for steric or charge/electrostatic stabilization. As a general introduction, then view these webinars (registration needed):

Metal colloids - their preparation, application and characterization

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W160218MetalColloids.html

Silver colloids and invisible ink

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W150902SilverColloidInvisibleInk.html

Other factors to bear in mind include what instrumentation you have for characterization. This will depend on the end application of your preparation. 2 techniques you'll need (and, in my view, don't even start unless you have access to them) are specific surface area (SSA) and ESCA/XPS for surface composition.

Saba Fatima

BTW, there can be no 'green synthesis' in the strict definition of the term, as the inorganic precursors are usually highly toxic e.g. AgNO3, HAuCl4.xH2O, H2PtCl6.yH2O etc.

Dear all, please take a look at the attached files. My Regards