It's a bit tricky to reduce MOF size. Nonetheless, depending on the method you are using, I suggest decreasing the precursor concentration and reaction time and increasing the agitation rate if applicable.

I have already synthesized particles. I want to reduce the size of as synthesized particles.

@Abhimanyu Singh

What kind of material nanoparticles did you get from your synthesis? I think Ali suggested to do it from the precursor, which is a good starting point to get reduced sizes of nanoparticles. Since you want to use your existing nanoparticles for further work, you may try to use a powerful ultrosonic bath to break down your large size particles into small size ones. Hope it helps.

Dear Abhimanyu,

Looking to your nice SEM pictures, I will say that the primary particles are even of 1-2 microns (please verify, not to be something wrong from my part).

WHAT TO DO to obtain particles of nanometer size (less than 100 nm)? If you are not able to change your conditions of synthesis as it is suggested by other RG colleagues, you maybe could try a colloidal grinding...

Please consider this information:

Producing nano particles by colloidal grinding

How does colloidal grinding? Do you know the RETSCH's Emax?

Subject: How does colloidal grinding? Do you know the Emax REtSCH mills?

https://www.marketizer.com/articles/producing-nano-particles-by-colloidal-grinding-3854224.htm

Good luck in finding the best solution and best regards,

Marius