Characterization of the microporosity of chromia- and titania-pillared montmorillonites differing in pillar density. I. Adsorption of nitrogen
Characterization of the microporosity of chromia- and titania-pillared montmorillonites differing in pillar density. I. Adsorption of nitrogen
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DOI：
10.1016/s1387-1811(99)00265-6
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发表时间：
2000-05
影响因子：
5.2
通讯作者：
M. Sychev;T. Shubina;M. Rozwadowski;Apb Sommen;D. Beer;V. Santen
中科院分区：
文献类型：
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作者：
M. Sychev;T. Shubina;M. Rozwadowski;Apb Sommen;D. Beer;V. Santen
The microporosity of chromia- and titania-pillared clays differing in pillar density has been explored. Nitrogen adsorption data determined at very low relative pressures were used. These data were analyzed by means of the αsmethod and the BET, Langmuir, Dubinin–Radushkevich and Dubinin–Stoeckli approaches. The applicability of these methods for determination of the PILCs' microporosity was studied. The surface area calculated by the αsmethod can be considered as a total surface area of the materials studied. The BET method underestimates, whereas the Langmuir approach overestimates, the total surface area of these solids. The Dubinin–Radushkevich method can be applied only to characterize textural features of PILCs exhibiting homogeneously distributed narrow micropores (<0.7–1.0nm width). The same holds for the Dubinin–Stoeckli relation. The method developed by Zhu et al. is useful for the determination of the porous structure of PILCs having a significant contribution of supermicropores (0.7–2.0nm width). A good agreement between the total micropore volume of the materials studied and that obtained from the αsmethod was found. All the methods applied demonstrated that these solids possess micropores over a broad pore-size range. Chromia-pillared montmorillonites contain a significant amount of ultramicropores (<0.7nm width), whereas titania-pillared clays show an important contribution of supermicropores. An alteration of the pillar density can provide a family of pillared clays that differ in the surface area, micropore volume, and micropore size distribution.
