I have been running DSC for porous materials but the results I got were quite ridiculous. For the solid porous materials, I obtained heat capacity above that of water, which I cannot reason at all. However, for the reference material activated carbon, the result was normal (below 2 J/g•K). The equipment I used was a cryogenic DSC which cools the sample down to -120 degrees before every measurement, but I don't believe this should have such an impact on the results. We also considered heat of adsorption, but activating sample before measurement did not help with the problem at all. Could someone please offer me some insight as to why this was the case?
Hi
please check the tightness of the pan which contains sample material. that might give ridiculous value in DSC .
Dear Ada Chen,
I don't know the real setup of your sample.
If some humidity, solvent residue in the synthesis procedure still trapped inside the porous, therefore, moisture freezes inside the porous materials, as you drop the temperature down to 120 K, the heat capacity may give unreasonable results when heated up.
Is there the possibility to have some humidity absorbed inside the porous?
As you sad, the activated carbon was ok. Activated carbon still have porous, it behaves similar.
I think the main reason is located on the initial porous absorption of your original sample.
You may treat the sample thermally before the DSC experiment.
Best regards,
WNM
If you work in N2 or argon there may still be a contribution from desorption. In that case I would recommend to switch to helium and see if it helps. Otherwise I don't know.
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