Dear Humayun Akhter

You can use Hydrazine hydrate. Hydrazine is a greener reducing agent and maintain pH high of the solution.

plz. visit links i think that will you.

https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#

https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#

Hello,

Yes pH can affects NPs size. 

You can get details from my recently published article.

Article Sasa borealis leaf extract-mediated green synthesis of silve...

Dear Humayun Akhter

You can use Hydrazine hydrate. Hydrazine is a greener reducing agent and maintain pH high of the solution.