Effects of Cerium Oxide Incorporation and Zeolite Cationic Form on ZSM-5 Catalysts for Glycerol Dehydration

NaZSM-5, HZSM-5, and Ce/HZSM-5 zeolites with a Si/Al ratio of 25 were synthesized via a hydrothermal method developed by our research group, which enables the formation of hierarchical ZSM-5 structures with micro and mesoporosity. These materials were evaluated as catalysts for the glycerol dehydration reaction. The incorporation of cerium oxide into HZSM-5 introduced redox properties that enhanced catalyst stability under oxygen-deficient conditions. When air was co-fed, the oxidative removal of carbonaceous deposits promoted sustained catalytic activity, with Ce/HZSM-5 maintaining consistent performance under both oxidizing and non-oxidizing environments. HZSM-5 also demonstrated stable activity in the presence of oxygen, benefiting from surface regeneration. In contrast, NaZSM-5 exhibited the lowest selectivity, producing a broader range of by-products, a behavior attributed to its lower surface area, limited mesoporosity, and reduced concentration of strong acid sites. These findings highlight the critical role of hierarchical structure, acidity, and redox functionality in enhancing the activity and selectivity of zeolite-based catalysts for acrolein production.

Graphical Abstract