Sciencemadness Discussion Board

Heterogeneous Catalysis

vinothan23 - 18-3-2012 at 22:33

How to decide metal loading based on surface area of the catalyst support?

Is there any thump rule available to decide active metal loading based on surface area of support material?

Is there any thump rule like number of active site per nanometer square of support material? etc.,

Kindly disscuss indetail. :)

Nicodem - 19-3-2012 at 06:11

Quote: Originally posted by vinothan23  
Kindly disscuss indetail. :)

The utmost we can do, is to discuss the lack of details. I can't speak for all of our members, but I for one cannot read your mind telepathically. Your post makes no sense whatsoever, simply because you do not provide the most basic information that would make your question answerable. Please read the posting guidelines in order to learn how to properly present your problem.

vinothan23 - 20-3-2012 at 02:28

Dear Nicodem,
Kindly apologize me. I will get back to you soon with more details.

Thanks.

vinothan23 - 26-3-2012 at 02:29

Catal Lett (2010) 138:215–223

in this above reference i read that

Dispersion of Cr={10^-18*NA}/{Surface area if AlF3*Mol.Wt AlF3}*(Cr/Al)

at the Cr/Al atomic ratio of 0.11 the dispersion of Cr is 12 atoms per nm2.

In another one patent US5281568, which states that loading of Zn based on working surface area of the catalyst.

If working SA is above 100 m2/gm Zn loading is 15-25% if it is 20-50 m2/gm Zn loading is 2-6% if it is less than 20 m2/gm Zn loading should be 0.5-1%.

So that i asked,

Is there any thump rule available to decide active metal loading based on surface area of support material?

Is there any thump rule like number of active site per nanometer square of support material?

How to decide metal loading based on surface area of the catalyst support?

Nicodem - 26-3-2012 at 09:26

Quote: Originally posted by vinothan23  
Is there any thump rule available to decide active metal loading based on surface area of support material?

Is there any thump rule like number of active site per nanometer square of support material?

How to decide metal loading based on surface area of the catalyst support?

You don't decide the catalyst loading just like that. You decide by measuring the catalyst activity. The catalyst loading for a process is a compromise between economy, minimal turnover number and reaction kinetics. Surface area doesn't tell the activity of the catalyst, though it can be expected that a catalyst with a higher specific surface area performs better than the same catalyst with a lower surface area, but there is no general and fully linear correlation. Any such correlation would be reaction specific, just like catalysts are always mechanism specific.
You appear to generalize catalyst as if the type and reaction they catalyze is irrelevant which is obviously not the case. It is not possible to describe complex systems with a single variable (they would not be called complex systems if this would be possible!).