(228a) Designing Zeolite Catalysts with Enhanced Diffusion Properties
AIChE Annual Meeting
2022
2022 Annual Meeting
Catalysis and Reaction Engineering Division
Catalyst Design, Synthesis, and Characterization IV: Zeolites
Tuesday, November 15, 2022 - 8:00am to 8:18am
A second class of zeolitic materials that will be discussed is core-shells, wherein a thin siliceous shell is epitaxially grown on the surfaces of aluminosilicate seed crystals. These core-shell configurations were realized for zeolites ZSM-5 (MFI) and ZSM-11 (MEL) where we have shown that the incorporation of siliceous shells via facile secondary growth enhances mass transport, leading to MTH catalysts with markedly improved lifetime and total turnover number. We will present these results along with a mechanistic interpretation wherein we have shown that the improved catalytic activity of core-shells is attributed to enhanced diffusion through the siliceous shell and surface passivation (i.e. reduced external coking). Our findings also reveal that a reverse configuration, the eggshell, produce pseudo nanosheets with a five-fold increase in catalyst lifetime and total turnovers compared to homogenous counterparts.