Catalytic fast pyrolysis of cellulose over Ce0.8Zr0.2-xAlxO2 catalysts to produce aromatic hydrocarbons: Analytical Py-GC × GC/MS
Analytical pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC × GC/MS) was employed for the on-line analysis of cellulose via catalytic pyrolysis with different catalysts and catalytic temperatures to study the products and aromatic hydrocarbons selectivity. The catalysts were subjected to characterization methods, including XRD, TEM, NH3-TPD, to investigate the effects of the physicochemical properties of the catalyst on the product distribution. Results showed that the Ce0.8Zr0.2-xAlxO2 could significantly promote the formation of aromatic hydrocarbons under 400–550 °C. A lower catalytic temperature (≤350 °C) favored the formation of furan compounds, and a higher catalytic temperature (≥450 °C) supported the formation of aromatic hydrocarbons. The relative peak area of the aromatics prepared by using the Ce0.8Zr0.15Al0.05O2 catalyst was the highest being 85.24% at 550 °C. Moreover, the selectivity of the single-ring aromatics, such as benzene, toluene and xylene, were significantly affected by the presence of the Ce0.8Zr0.2-xAlxO2 catalysts. The higher total acidity of Ce0.8Zr0.15Al0.05O2 favored the formation of benzene and toluene. Additionally, the Ce0.8Zr0.15Al0.05O2 catalyst had a great thermal stability. The catalyst recycling tests showed that the Ce0.8Zr0.15Al0.05O2 catalyst can be reused five times to produce aromatic-rich bio-oil via catalytic fast pyrolysis.