Heterogeneity of nano-sized zeolite crystals

Abstract

Analytical characterization and evaluation of performance of zeolite catalysts are normally done under the assumption of a homogeneous batch. However, it is known that in the same batch particles of the zeolite ZSM-5 can be very different one from another, regarding their aluminum content and catalytic performance. Here, we quantify the extent of this heterogeneity within a singular synthesis batch of nanocrystalline ZSM-5, through the analysis of single crystalline individua. We found that the overall aluminum content was distributed unequally between two kinds of crystal populations. Cornered crystals contained three times more aluminum than round-shaped crystals. This observation connects morphological differences to the chemical composition of each zeolite crystal for the first time. This finding could provide a means for performance optimization in zeolite synthesis.