High ratio of Ce3+/(Ce3+-Ce4+) enhanced the plasma catalytic degradation of n-undecane on CeO2/γ-Al2O3

n-Undecane (C11) is the main component of volatile organic compounds (VOCs) emitted from the printing industry, and its emission to the atmosphere should be controlled. In this study, a dielectric barrier discharge reactor coupled with CeO2/gamma-Al2O3 catalysts was used to degrade C11. The effect of the chemical state of CeO2 on C11 degradation was evaluated by varying the CeO2 loading on gamma-Al2O3. The C11 conversion and COx selectivity were as high as 92% and 80%, respectively, under mild reaction conditions of energy density 34 J/L and 423 K to degrade 134 mg/m(3) C11 in a simulated air using 10 wt%CeO2 impregnated on gamma-Al2O3. After analyses using in-situ plasma diffuse reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry, it was found that most of C11 were degraded to CO2, and the main by-products on catalyst surfaces were alcohols and ketones. It was concluded from X-ray photoemission spectroscopy that the good performance of the 10 wt%CeO2/gamma-Al2O3 catalyst was due to its high Ce3+/(Ce3++Ce4+) ratio as well as the oxygen vacancies. The Ce3+/(Ce3++Ce4+) ratio of CeO2 on gamma-Al2O3 is crucial for the degradation of C11, providing a further roadmap for the plasma catalytic oxidation of alkanes.

Automated summary

In this study, a dielectric barrier discharge reactor coupled with CeO2/gamma-Al2O3 catalysts was used successfully to degrade n-Undecane emitted from the printing industry, with high C11 conversion to CO2 and by-products including alcohols and ketones. The chemical state of CeO2 on gamma-Al2O3 was found to significantly influence the degradation of n-Undecane, with the catalyst having a high Ce3+/(Ce3++Ce4+) ratio showing better performance.