a) Schematic of Mg impregnation step and formation of Mg clusters. b) C clusters in APT data with examples of large cage crossing clusters and small single cage clusters.
Scientific Achievement
Atom probe tomography (APT) was used to image Mg nanoclusters within Mg-impregnated SSZ-13 zeolites - an anti-correlation between Mg and the deactivating coke species was discovered.
Significance and Impact
Work demonstrated, for the first time, the ability to directly image the spatial distribution of Mg atoms within zeolites, which improves the understanding of how Mg impregnation improves zeolite catalyst longevity.
Research Details
- Zeolites impregnated with Mg and subjected to a methanol-to-hydrocarbon reaction for different times.
- Operando UV−vis diffuse reflectance spectroscopy and X-ray diffraction showed longer catalyst lifetime, higher propylene selectivity, and slower deactivation rate attributable to suppressed formation of aromatic intermediate species.
- APT revealed Mg clusters around catalytically active Al atoms and anti-correlation between Mg atoms and coke molecules.
S.H. van Vreeswijk, et al., “Detecting Cage Crossing and Filling Clusters of Mg and C Atoms in Zeolite SSZ-13 with Atom Probe Tomography,” JACS Au 2, 2501-2513 (2022).
Work performed at the Center for Nanophase Materials Sciences and Utrecht University
