Assessing Molecular Transport Properties of Nanoporous Materials by Interference Microscopy: Remarkable Effects of Composition and Microstructure on Diffusion in the Silicoaluminophosphate Zeotype STA-7

作者：Tzoulaki Despina^*; Heinke Lars; Castro Maria; Cubillas Pablo; Anderson Michael W; Zhou Wuzong; Wright Paul A; Kaerger Joerg

来源：Journal of the American Chemical Society, 2010, 132(33): 11665-11670.

DOI：10.1021/ja104016n

The influence of the chemical composition and of the storage and activation protocol on the diffusion of methanol into strongly chemically zoned crystals of the silicoaluminophosphate zeotype STA-7 has been investigated by interference microscopy. Analysis of the evolution of transient intracrystalline concentration profiles reveals that just-calcined SAPO STA-7 crystals with lower Si content (Si/(Si + P) = 0.18) exhibit higher surface permeability and bulk diffusivity than those with higher Si content (S/(Si + P) = 0.37). Remarkably, crystals with the higher Si content which were stored in the calcined form crack during activation along planes of weakness already present in the as-prepared crystals, creating fresh surfaces through regions of lower Si that are much more easily penetrated by the adsorbing methanol than are the original surfaces.

• 出版日期2010-8-25