| Summary: | Catalytic ozonation, with enhanced efficiency and reduced byproduct formation at lower temperatures, proved to be efficient in ethyl acetate (EA) degradation. In this work, MMn<sub>2</sub>O<sub>4</sub> (M = Cu, Co, Ni, Mg) catalysts were prepared via a redox-precipitation method to explore the catalytic ozonation mechanism of EA. Among all the catalysts, CuMn exhibited superior catalytic activity at 120 °C, achieving nearly 100% EA conversion and above 90% CO<sub>2</sub> selectivity with an O<sub>3</sub>/EA molar ratio of 10. Many characterizations were conducted, such as SEM, BET and XPS, for revealing the properties of the catalysts. Plentiful active sites, abundant oxygen vacancies, more acid sites and higher reduction ability contributed to the excellent performance of CuMn. Moreover, the addition of NO induced a degree of inhibition to EA conversion due to its competition for ozone. H<sub>2</sub>O had little effect on the catalytic ozonation of CuMn, as the conversion of EA could reach a stable platform at ~89% even with 5.0 vol.% of H<sub>2</sub>O. The presence of SO<sub>2</sub> usually caused catalyst deactivation. However, the conversion could gradually recover once SO<sub>2</sub> was discontinued due to the reactivation of ozone. A detailed reaction mechanism for catalytic ozonation was proposed via in situ DRIFTS measurements and DFT calculations.
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