Sol-gel enhanced mesoporous Cu-Ce-Zr catalyst for toluene oxidation

ABSTRACT

The bulk-phase Cu-Ce-Zr catalyst BP-gel was prepared by the sol-gel method and investigated for the oxidation of toluene in a fixed-bed reactor. For comparison, other bulk-phase catalysts (thermal decomposition (BP-td), solid-state reaction (BP-sr)) and supported catalysts (incipient wetness impregnation (S-iwi), saturated impregnation (S-si)) were tested. The results showed that the catalytic activities were in the following order: BP-gel>S-si>S-iwi>BP-td>BP-sr. The BP-gel catalyst, which has a mesoporous structure, is beneficial for the mass transfer of reactant molecules. The thermal stability of the BP-gel catalyst was improved by the introduction of ZrO₂. Bulk CuO in the catalysts reduced their activity because the synergetic effect between CuO and CeO₂ decreased. The low-temperature reducibility, large pore sizes, rich oxygen vacancies, and active oxygen species contributed to the highest activity of the BP-gel, with a T₉₀ as low as 219°C, and no deactivation was observed during the 72 h stability test at the set temperature.

KEY WORDS:

• Cu-Ce-Zr Catalyst
• Catalytic Oxidation
• Preparation Method
• Toluene

Additional information

Funding

We gratefully acknowledge financial support from the National Natural Science Foundation of China (Numbers 51776216, 51736010), and the Science Foundation of the Chinese Academy of Sciences (LHD2017QN05).