I have carried out a hydrogen chemisorption experiment and have determined, from the linearized Langmuir isotherm, the volume of hydrogen required for mono layer coverage (i.e 5.5 ml/g). How do I calculate metallic dispersion from this value.
Dispersion=S M N/100L
where S is a stoichiometric factor. That means for example in the case of Pt and H2 chemisorption, one molecule of H2 dissociate to to give two atoms to be chemisorbed each atom over Pt
N is the amount of monolayer, experimentally obtained from Langmuir isotherm (in static experiments) or directly from dynamic (flow experiments) in mol/g
M is the molecular weight of the metal (g/mol)
L is the weight percentage of metal in your solid. This value should be measured (for example by ICP). You should not use the theoretical percentage, I mean the percentage that you suppose after preparation.
Dispersion=S M N/100L
where S is a stoichiometric factor. That means for example in the case of Pt and H2 chemisorption, one molecule of H2 dissociate to to give two atoms to be chemisorbed each atom over Pt
N is the amount of monolayer, experimentally obtained from Langmuir isotherm (in static experiments) or directly from dynamic (flow experiments) in mol/g
M is the molecular weight of the metal (g/mol)
L is the weight percentage of metal in your solid. This value should be measured (for example by ICP). You should not use the theoretical percentage, I mean the percentage that you suppose after preparation.
You can also calculate the ASA (active surface área) from the monolayer coverage value
Thank you Maria. but to further understand, the units of N in your example are mol/g. is that per gram of active metal or per gram of the total solid.
The units of N are referred to mass of solid. That means the amount of solid that you have weigthed to perform the chemisorption analysis
what if we are given with active metal area but not the amount of monolayer??
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