I have prepared PtCu (Platinum-copper) particles (don't know yet, if they are nano) and as the product was obtained, after separating & washing, the particles were re-dispersed in ethanol. They give a very fine dispersion initially, but after more or less an hour the particles seem to be agglomerating and settling down. I want to use these particles for electrocatalysis of alcohols and as they are getting agglomerated, the electrocatalytic activity obtained wouldn't be accurate. Please give suggestions, if I need to change my dispersion medium.
What other dispersion mediums can I use ?
Could it be that the particles have attained a certain shape (dendrites, hexapods etc kinds) that is causing agglomeration that quick ?
Could it be that the particles might be too big ? (It doesn't seem so, though)
What other reasons could there be, that these particles are getting agglomerated ?
Thanks
- Calculate the density of your particles in the system. PtCu is pretty dense. Your comment that the particles are too big is absolutely correct
- Carry out a Stokes' Law calculation for your particles in EtOH and calculate what size they must be to remain in colloidal suspension
- A DLS measurement combined with the above information will confirm or deny the presence of nanoparticles
- Your key (and problem) comment is " the particles were re-dispersed in ethanol".... I assume that the particles were prepared by a aqueous reduction mechanism
- View the webinars below:
Nov 11th, 2008. Dispersion and nanotechnology http://tinyurl.com/hpywsge
November 3rd, 2015 Adhesion and cohesion http://tinyurl.com/zwb2wlh
Dear Muhammad,
I think the surface ligands on the PtCu been washed out mostly. May be you can re-disperse PtCu particles in EtOH contains ligands.
For the morphology of particles, you may obtain some TEM images.
Hope it will help you.
Best Regards,
Ray
Thanks alot for your guidance Sir Alan F Rawle and Zhourui Xu
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