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Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
Published on: August 17, 2019
Zeolite Catalysts Prepared with Maximum Brønsted Acidity Reveal a Dominant Contribution from Inaccessible Sites
Omio Rani Das1, Ismaeel Alalq2, Jacob Crouch2
1School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
Journal of the American Chemical Society
|June 26, 2026
Summary
Acid sites within zeolite Y sodalite cages significantly impact catalyst reactivity. Maximizing these inaccessible sites, particularly with La3+ exchange, greatly enhances catalytic activity for hydrocarbon cracking.
Area of Science:
- Catalysis
- Materials Science
- Physical Chemistry
Background:
- Zeolite Y catalysts possess Brønsted acid sites (BASs) in both large supercages and small, inaccessible sodalite cages.
- Sodalite cage windows (0.26 nm) restrict access for many hydrocarbons, limiting the perceived role of these sites.
Purpose of the Study:
- To investigate and quantify the contribution of inaccessible sodalite cage acid sites to HY catalyst reactivity.
- To prepare HY catalysts with varying acid site densities, including a theoretical maximum.
Main Methods:
- Catalyst preparation with controlled acid site densities.
- Spectroscopy and isotopic exchange with bulky hydrocarbons.
- High-temperature isooctane cracking experiments.
- Density Functional Theory (DFT) calculations.
Main Results:
- Acid sites within intact sodalite cages are a dominant factor in HY catalyst reactivity.
- Quantified the significant contribution of sodalite cage BASs using varied experimental conditions.
- Demonstrated that commonly used methods may underestimate total active site contributions.
Conclusions:
- Brønsted acid sites in inaccessible sodalite cages critically control HY catalyst performance.
- Framework flexibility and site exchange mechanisms are plausible.
- Tuning sterically occluded acid sites in zeolites offers a pathway for enhanced catalytic activity.
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