4.7 Review

Synthesis strategies to control the Al distribution in zeolites: thermodynamic and kinetic aspects

Journal

CHEMICAL COMMUNICATIONS
Volume 59, Issue 7, Pages 852-867

Publisher

ROYAL SOC CHEMISTRY
DOI: 10.1039/d2cc05370e

Keywords

-

Ask authors/readers for more resources

The activity and selectivity of acid-catalyzed chemistry are influenced by the Bronsted and Lewis acid sites generated by Al substitutions in zeolite framework. Close proximity of two Al atoms in high-silica zeolites can enhance the performance of redox catalysts. Various strategies have been developed to control the Al incorporation, including variation in extra-framework components, isomorphous substitution, and control over the (alumino)silicate network. This review provides guidance on efficient methods to prepare fine-tuned zeolites with desired chemical properties.
The activity and selectivity of acid-catalyzed chemistry is highly dependent on the Bronsted and Lewis acid sites generated by Al substitutions in a zeolite framework with the desired pore architecture. The siting of two Al atoms in close proximity in the framework of high-silica zeolites can also play a decisive role in improving the performance of redox catalysts by producing exchangeable positions for extra-framework multivalent cations. Thus, considerable attention has been devoted to controlling the Al incorporation through direct synthesis approaches and post-synthesis treatments to optimize the performance as (industrial) solid catalysts and to develop new acid- and redox-catalyzed reactions. This Feature Article highlights bottom-up synthetic strategies to fine-tune the Al incorporation in zeolites, interpreted with respect to thermodynamic and kinetic aspects. They include (i) variation in extra-framework components in zeolite synthesis, (ii) isomorphous substitution of other heteroatoms in the zeolite framework, and (iii) control over the (alumino)silicate network in the initial synthesis mixture via in situ and ex situ methods. Most synthetic approaches introduced here tentatively showed that the energy barriers associated with Al incorporation in zeolites can be variable during zeolite crystallization processes, occurring in complex media with multiple chemical interactions. Although the generic interpretation of each strategy and underlying crystallization mechanism remains largely unknown (and often limited to a specific framework), this review will provide guidance on more efficient methods to prepare fine-tuned zeolites with desired chemical properties.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available