Catalytic Upgrading of Cellulose Pyrolysis Volatiles over Ce Modified Hierarchical ZSM‑5 Zeolite: Insight into the Effect of Acid Properties on Light Aromatics and Catalyst Stability

CeO₂ receives extensive researches as an active component due to its providential catalytic center and favorable reducibility. Herein, a series of Ce-modified hierarchical ZSM-5 zeolites (FZ5) were prepared by HF (0.5 mol/L) etching followed by impregnation with different Ce loadings. The role of incorporating extra-framework Ce elements was assessed by catalytic upgrading of the cellulose pyrolysis volatiles to produce light aromatics (LAs). Introducing CeO₂ could effectively regulate the acid properties of catalysts with an increase in Lewis acid sites and a decrease in Brönsted acid sites, which could significantly improve the catalytic performance. As a result, the selectivity toward LAs were significantly enhanced and the coke content dramatically decreased. The highest selectivity to LAs and the lowest coke content obtained over 1.0Ce-FZ5 zeolite (loading 1.0 wt % Ce) were 84.0% and 2.42 wt %, respectively. Additionally, the 1.0Ce-FZ5 catalyst exhibited excellent stability, maintaining nearly 90% carbon yield of LAs after the seventh regeneration test. CeO₂ modification opened a simple and feasible way for promoting the LAs selectivity and catalyst stability during the reforming of biomass volatiles.