(165b) Adsorption, Phase and Hysteresis Behavior of Fluids in Ordered Mesoporous Materials with Pseudo-One Dimensional and Three-Dimensional Pore Systems

We performed a comprehensive gas adsorption study of large pore silica materials with 3-D cubic Ia3d structure (KIT-6) is reported. Pore condensation and hysteresis behavior of nitrogen (77.4 K) and argon (77.4 K and 87.3 K) were studied in KIT-6 silicas of different porosities and various mean pore diameter. We compared the sorption and phase behavior of N2 and Ar confined in the 3D cubic porous system with their behavior in a series of corresponding SBA-15 silicas (which consist of a pseudo-one-dimensional pore system) in order to address the following points: (i) Is the adsorption, pore condensation and hysteresis behavior of fluids in pseudo-one dimensional pore systems comparable with the behavior in ordered three dimensional systems; (ii) To which extend can the single pore model (which is mostly used in pore characterization) be used for the pore size analysis of ordered pore networks? An advanced analysis of a large data set allows us to discuss these questions in great detail, which is of fundamental importance for an understanding of the origin of hysteresis in ordered mesoporous materials and an accurate textural characterization of nanoporous materials.