Determination of Microporous and Mesoporous Surface Areas and Volumes of Mesoporous Zeolites by Corrected t ‐Plot Analysis
Résumé
Zeolites are well-known microporous catalysts, involved in many industrial applications. Their microporosity yet impedes diffusion of bulky molecules/feedstocks. To overcome this drawback, zeolites with bimodal porosity, e.g. micropores and mesopores were developed during the last decades. In this context, it is important to develop/use methods able to evaluate accurately the textural properties of micro-/mesoporous zeolites. t-Plot is commonly used for determining the micro-and mesopore surface areas and pore volumes. However, previously we showed that the classical t-plot analysis overestimates the mesopore surface areas and underestimates the micropore volumes for FAU-Y micro-/mesoporous zeolite. Measurements performed with mechanical mixtures of FAU-Y and MCM-41 allowed us to provide corrections to the t-plot analysis. These corrections were up to date limited to FAU structured zeolites. In the present work, we present specific corrections of the t-plot for a broader series of zeolites including MFI, *BEA and MOR, based on a set of mechanical mixtures of zeolites and MCM-41. Minor correction factors were required for MOR, whilst for MFI and *BEA similar corrections as for the FAU-Y were inferred for the micropore volume. As far as the surface area is concerned higher correction factors were required for MFI compared to *BEA. This corrected t-plot analysis was applied to characterize a great variety of mesoporous zeolites prepared by micelle-templating following a two-steps procedure.
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