Will the result obtained for surface area measurement of a sample (e.g activated carbon) using CO2 as probe molecule be different from the one obtained when N2 is used as probe molecule.
Also, if there is a difference, then which probe molecule is advisable to use in obtaining a good result when determining the textural characteristics of microporous activated carbon
Yes definitely the not only BET surface area Isotherm itself will be different.
1) CO2 is bigger in size than N2. Thus its area of cross section of molecule is different. 2) CO2 has different affinity than N2 over the substrate.
These two factors will effect surface area. N2 adsorption below 0.3 partial pressure should give higher and more accurate surface area than CO2 adsorption.
Hope this is helpful.
Thank you Mithil Fal Desai.
Following the answer you provided, that means to obtain a good result for Microporous materials, N2 adsorption will be a good idea as compared to CO2?
Yes! As CO2 is not as inert chemically as N2 for adsorption (Physisorption).
Thank you so much Mithil Fal Desai for your time and clarification