Shedding electrons on ADOR zeolite structures – Structure determination by 3DED

Abstract

Three-dimensional electron diffraction (3DED) offers a powerful alternative to single-crystal X-ray diffraction (SCXRD) for the structure determination of crystalline materials with small-sized crystals (usually nanometre-sized) or crystals with intergrowths, often produced during zeolite synthesis. ADOR is a synthesis strategy of novel daughter zeolites from well-known parent germanosilicates. Structure determination of such ADOR zeolites is challenging due to the presence of aggregated intergrowths, and often small-sized crystals. This work demonstrates the application of continuous rotation electron diffraction (cRED), a type of 3DED, for the rapid structural characterisation of zeolites produced by ADOR approach. cRED can be performed in a transmission electron microscope and the structure of a studied material can be obtained rapidly. We propose a unified workflow for the structure determination of ADOR daughter materials. This workflow involves the initial structural investigation and determination of the parent material, followed by the utilization of this knowledge to facilitate the subsequent structure determination of the daughter material. Investigation strategy was shown to be uniform, as presented for ADOR transformation of two different parent germanosilicates. This approach is a tool allowing prompt recognition of new ADOR zeolites at the early stage of their synthesis and can be used for a feedback-based optimisation of synthesis conditions.