Porosity and surface properties of mesoporous silicas and their carbon replicas investigated with quasi-equlibrated thermodesorption of n-hexane and n-nonane
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Adsorption of n-hexane and n-nonane on mesoporous micelle-templated silicas (SBA-15 and MLV—multilayer vesicle) and on their carbon replicas (CMK-3 and OCM—onion-like carbonaceous material) was studied by means of quasi-equilibrated thermodesorption technique, utilising a standard TPD setup with a chromatographic detector. Analysis of n-hexane adsorption isobars, determined from the thermodesorption profiles, revealed substantial heterogeneity of the adsorption sites present in the carbonaceous materials. The pore size distributions calculated from the thermodesorption profiles of n-nonane for both siliceous and carbonaceous materials were in agreement with those obtained from the low-temperature nitrogen adsorption isotherms. They confirm an uniform structure of mesopores in SBA-15, CMK-3 and OCM as well as a more complex structure of mesopores in the MLV materials.
KeywordsMesoporous silica Carbon replica Pore size distribution Quasi-equilibrated thermodesorption n-alkanes
This work has partially been supported by the Polish Ministry of Science and Higher Education with a grant no. N507 108 32/3175. The authors are grateful to Dr. K. Erdmann and Prof. J. Kornatowski for their valuable help.
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