(289e) Tuning Zeolite-Supported Metal Catalysts By Varying Heteroatom Distribution and Composition: Characterization By Catalysis and Probe Molecule Adsorption Spectroscopy
AIChE Annual Meeting
2021
2021 Annual Meeting
Catalysis and Reaction Engineering Division
Advances in Zeolite Science and Technology IV (Virtual)
Wednesday, November 17, 2021 - 2:15pm to 2:35pm
The stabilization of active metal sites during ethane dehydrogenation was influenced by availability of zeolite framework Al sites; in the absence of available Al sites, Cr sites quickly deactivated. It was also found that greater Cr/Al molar ratios yielded a greater abundance of electron-rich Cr2+ species after reduction. This trend correlated with enhanced ethane dehydrogenation activity but decreased stability in time-on-stream studies. Both high activity and enhanced stability were achieved with Cr/Ca-ZSM-5. Increasing in electron density by varying the zeolite heteroatom composition in the order: [Fe] > [Ga] > [Al] was observed via CO adsorption on supported Ni cations. C2H4 dimerization activity increased with increasing electron density of the Ni cation. Despite similarities in reported acid site strength, the solid acid sites on [Fe]-Beta in this work had significantly lower activity than those on [Ga]-Beta for the skeletal isomerization of linear butenes as well as C2H4 dimerization. Taken together, these results demonstrate the ability of heteroatom distribution and composition to further tune adsorption and catalysis by zeolite-supported metals.