Catalytic combustion of chlorobenzene over VOx/CeO2 catalysts

• VOx/CeO2 catalysts with various loadings of VOx were prepared by wet impregnation method.
• VOx was identified as the forms of monomeric, oligomeric, or polymeric VOx and CeVO4.
• Monomeric VOx promoted oxygen vacancy and hence increased in surface oxygen and oxygen mobility.
• VOx/CeO2 catalysts with monomeric VOx showed high stable activity for chlorobenzene oxidation.
• The addition of VOx greatly retarded the formation of dichlorobenzene.

VOx/CeO2 catalysts with various loadings of VOx were prepared by wet impregnation method and used in catalytic combustion of chlorobenzene (CB). Characterized by XRD, Raman, XPS, HRTEM, H2-TPR, and O2-TPD revealed that VOx on CeO2 support was identified as monomeric, oligomeric, or polymeric VOx and CeVO4. Monomeric VOx promoted oxygen vacancies and hence increased in surface oxygen and oxygen mobility. VOx/CeO2 catalysts had considerable activity for CB combustion. The highest value of TOF (0.023 min−1) was obtained on VOx/CeO2 catalysts with monomeric VOx. VOx greatly improved the stability of VOx/CeO2 catalysts through retarding the exchange of Cl for basic surface lattice oxygen of CeO2. High stability maintained at 285 °C for at least 1000 min. In situ FTIR and Raman indicated that CB adsorption on CeO2 was much stronger than VOx, and different reaction pathways were related to different types of oxygen species existing on the surface of VOx/CeO2 catalysts.

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