Highly Active MnO2 for the Catalytic Combustion of Ethyl Acetate at Low Temperature

Abstract A highly active MnO 2 catalyst with mixed crystal forms for the catalytic combustion of ethyl acetate was successfully prepared. The characterization results showed that increasing the hydrothermal temperature promotes the transformation of MnO 2 from α phase to β phase, and the microscopic morphology gradually evolves from stacked granular to rod-like structure, thereby obtaining biphasic mesoporous MnO 2 . In particular, the lattice fringes of α and β phases observed in HRTEM further proved that MnO 2 possesses a dual-phase structure. XPS verified that MnO 2 –180°C has the highest O ads /O latt (0.45) and Mn 3+ /Mn 4+ (0.90) ratio, and as oxygen vacancies appear together with the formation of Mn 3+ ions. The MnO 2 –180°C catalyst displayed the best performance that T 99 (the temperature needed for 99% conversion) is as low as 170°C even though under the high space velocity of 68 000 mL g –1 h –1 . Furthermore, the catalytic activity remained unchanged after 24 h of continuous reaction, demonstrating excellent low-temperature catalytic performance and good stability.