Why the desorption points of Ag-based Coordination-Polymers stopped at 0.3 P/P0, it should come down to at least P/P0=0.1. some examples of the N2 adsorption/desorption isotherm which was reported in literature was listed below:
1) ACS omega 4.5 (2019): 8926-8934.
2) Materials Research Express, 6(12), 125071.
Dear Masoud Mohammadi
This is in dead a very interesting question. In this regard, you may easily take help from the following articles:
https://theses.ncl.ac.uk/jspui/bitstream/10443/2119/1/Armstong%2C%20J.%2013.pdf
https://orca.cardiff.ac.uk/55717/1/U584236.pdf
and the book:
High Solid Dispersions
https://link.springer.com/book/10.1007%2F978-3-642-16382-1
Dear Masoud,
I don't know if it was you or someone else who did this analysis. I don't know how they degassed it. Because we normally we send the samples to outside laboratories.
All these problems are noise coming from the experiment. You would need to have a larger amount of sample for the analysis, take special care during the Helium calibration (dead volume is probably slightly wrong, and this makes a difference for very low surface areas).
It can also be caused by a leak in your sample tube. Check it by performing a leak test with your instrument. You can manually look at a leak on your instrument by using an empty sample tube connected to your device. Then put it under vacuum and when the ultimate vacuum is reached, isolate the sample tube and look at the pressure: it should remain stable or increase slightly. A proper degassing of your sample is ensured when the ultimate vacuum of your pump is reached during the operation.
If all of these are good and the instrument is functioning properly, then try to perform the pretreatment (degassing) for a longer time, as small amounts of impurities may desorb at lower pressure.
Usually, we perform degassing during the night to allow sufficient time for degassing.
Best regards.
BAOUCH Zakrya.
It may occur because of interactions between gas and material surface . These interactions may stabilize and trapped gas molecules in the pores hence you could see these kind of desorption diagrams.