Micro‐ and Nanoscale Heterogeneities in Zeolite Beta as Measured by Atom Probe Tomography and Confocal Fluorescence Microscopy

Abstract

AbstractMicro‐ and nanoscale information on the activating and deactivating coking behaviour of zeolite catalyst materials increases our current understanding of many industrially applied processes, such as the methanol‐to‐hydrocarbon (MTH) reaction. Atom probe tomography (APT) was used to reveal the link between framework and coke elemental distributions in 3D with sub‐nanometre resolution. APT revealed 10–20 nanometre‐sized Al‐rich regions and short‐range ordering (within nanometres) between Al atoms. With confocal fluorescence microscopy, it was found that the morphology of the zeolite crystal as well as the secondary mesoporous structures have a great effect on the microscale coke distribution throughout individual zeolite crystals over time. Additionally, a nanoscale heterogeneous distribution of carbon as residue from the MTH reaction was determined with carbon‐rich areas of tens of nanometres within the zeolite crystals. Lastly, a short length‐scale affinity between C and Al atoms, as revealed by APT, indicates the formation of carbon‐containing molecules next to the acidic sites in the zeolite.