Many bioactive compounds such as terpenoids, glycosides, steroids,

flavonoids, and phenolic acids are present in plant extract responsible for the reduction of silver ions to get silver nanoparticles.

Article Novel Green Synthesis and Characterization of the Antioxidan...

See also this article on green synthesis of silver nanoparticles.

Variety of herbs can be used for synthesis of Ag NPs

Also fruit extracts

Edible oils etc

You can use Tulsi, garlic, neem, etc use coprecipitation method.

Agree

We found that flavonoid molecules are involved in the reduction of ions to metal nanoparticles. We found that the hydroxyl group in the benzene ring of the flavonoid is reduced to the quinone group.

Article Preparation and bactericidal properties of silver nanopartic...

Article Preparation and bactericidal properties of silver nanopartic...

See also our articles on the mechanism of obtaining gold nanoparticles by green synthesis.

Benzalkonium chloride can also play an important role. Don't know people have used it or not but yes mostly this is used. If we are preparing a surfactant.

It's depends on the reducing agent present in biomolecules especially polyphenols compounds which react as reducing and capping agents

Many bioactive compounds such as terpenoids, glycosides, steroids,

flavonoids, and phenolic acids are present in plant extract responsible for the reduction of silver ions to get silver nanoparticles.

Article Novel Green Synthesis and Characterization of the Antioxidan...

See also this article on green synthesis of silver nanoparticles.

Heating of silver nitrate in aq. pvp soln can also a green synthesis

phenolic and aldehydic compounds in extract reduce to prepare Ag Nano

B R Siddharth The statement you make in your question ('silver nano particles are produced by plants called green synthesis') is incorrect. Plants do not make silver nanoparticles as no plant possesses or synthesizes Ag compounds. The silver comes from an externally added silver compound such as the diammine complex. Any plant extract will have to be acting as a reducing agent in order to produce silver or silver oxide particles. See also:

Silver colloids and invisible ink

https://www.brainshark.com/malvern/vu?pi=560497681&b=1&tx=120486&c1=22

Further, the question 'What are the compounds mainly responsible for green synthesis of silver nano particles ?' is correctly answered by "the compounds such as silver nitrate and the silver diammine complex'...

The only thing responsible for nano material synthesis is that which having oxidation and reduction capability. Plant convert AgNO3 into Silver NP, because of proteins. when the plant powder are pour in water or ethanol, the plant proteins are mix in water. After all when you treat this extract with AgNO3, the Ag of AgNO3 reduce into NP.

Like wise bacteria or fungi produce some types of secondary metabolites. which are protein and having capability to reduce AgNO3 into Ag Np. B R Siddharth

Alan F Rawle Dear sir, i already mentioned the components use for Np

Silver Nitrate cannot be reduce into Ag Nps. In green synthesis proteins or anything else which having the capability of reduction can reduce the AgNO3 into Ag Np

Mian Adnan Kakakhel I'm sure you have some typo in your comment 'Silver Nitrate cannot be reduce into Ag Nps'. There are many reducing agents that will carry this (AgNO3 → Ag0) reaction from hydrogen, through borohydrides, to hydrazine hydrate as well as any other appropriate reducing agent. The key is that the silver comes from an appropriate silver compound and not from any plant. I repeat that silver is not produced by plants. It's mined from ores in the ground.

Several biomolecules including protein, polysaccharides etc. can play the role for reduction and stabilization

Article Individual and Combined Effects of Extracellular Polymeric S...

Actually, if you follow some of 12 green chemistry principles then it became greener process in any chemical reaction. In case of silver nanoparticles, you need silver salts, capping or stabilizing agents and reducing agents. If you replace toxic capping agents and reducing agents by greener chemicals that became green synthesis. For example you can replace borohydride with glucose or plant extracts.

Yeakub Zaker You are correct. One important point is that the most toxic chemical in all of these syntheses is almost certainly the silver salt precursor (AgNO3, Ag(NH3)2NO3 etc).

Alan F Rawle This point is also important about salt. Actually there is an article about reducing toxicity of chemicals for the synthesis of CdSe/CdTe quantum dot where they replace intermediate precursor to reduce toxicity. Reference article: Article Formation of high-quality CdTe, CdSe, and CdS nanocrystals u...

In case of Silver nanoparticles, if we are able to convert all Ag+ to Ag nanoparticles then, we need not to worry about their toxicity. There is one example where yield was about 90%. Article High-Yield Paste-Based Synthesis of Thiolate-Protected Silve...

One point for the discussion need not to forget, if we need desired products of Ag NPs it might be not possible to avoid some toxic chemicals (AgNO3/Borohydride)

Yeakub Zaker On the surface of all 'silver' particles in air then all the species will be fully oxidized - that it silver will be in the +1 oxidation state; not silver metal. Easily shown with XPS. It's this surface that interacts with its surroundings and Ag+ is slightly soluble and is the active bactericide (possibly the reason for making the Ag nanoparticles in the first place). Silver metal is basically inert as it's not soluble in water. Have a look at the webinar I put in my first posting for more background.

One can protect silver metal with capping agents or polymers (as you indicate) but then the bactericide applications of the Ag nanoparticles are negated and there may be other issues with such systems.

When I produced Ag (and other metallic and alloy) colloids in the past, I always avoided borohydride reduction as the product was always contaminated with significant amounts of B. My preference was hydrazine hydrate solutions (5 or 10%) or hydrogen, H2, depending on the end application.

Why r v debating this.

It is such a simple and obvious thing in nano particularly of silver nanoparticle.

Let finish this discussion.

Pawan Kumar Khanna A discussion cannot be 'finished' in ResearchGate. Only the participants can end it by not posting. You'll be aware of other questions that are well past their sell-by date:

• https://www.researchgate.net/post/What_do_you_think_about_single_author_paper (7971 'answers')
• https://www.researchgate.net/post/Scholars_having_RG_Score_above_100 (2758 answers)