Dear Mostafa,
many thanks for sharing this very interesting technical question. Actually, I never thought about this problem, and as synthetic chemists we have only limited experience in catalysis. However, I just came across a potentially useful article which might help you in your analysis. Please have a look at the following paper:
Correlation between catalytic activity and bonding and coordination number of atoms and molecules on transition metal surfaces: Theory and experimental evidence
This article is freely accessible on the internet (please see the attached pdf file).
Good luck with your research!
Dear Frank T. Edelmann
As usual your friendly advises are helpful. Thank you so much .
Cobalt (and Nickle) are often combined with Molybdenum for use as Hydrotreating (Sulfur, Nitrogen and other contaminant removal) and Hydrogenation/Aromatics Saturation
Rick Manner Thank you .
I want to find a good slab of Cobalt catalyst .
This link might help:
Catalysts | Hydrotreating | Albemarle
https://www.albemarle.com/businesses/catalysts/hydroprocessing-catalysts/hydrotreating