Investigation of defect-rich CeO2 catalysts for super low-temperature catalytic oxidation and durable styrene removal
2022
Zhang, Ying | Zhang, Liming | Lu, Jichang | Liao, Wei | Zhang, Jin | Gao, Xiaoya | Luo, Yongming | Zhu, Wenjie
Spherical cerium dioxide (CeO₂–S) nanoparticles were successfully prepared using a solvothermal method, and their performances in catalytic oxidation reactions were studied. The CeO₂–S catalyst showed superior low-temperature catalytic activity for styrene removal (T₉₀ = 118 °C, GHSV = 18,000 h⁻¹) compared with commercial CeO₂. The characterization results showed that there were numerous oxygen defects in CeO₂–S that were key to its catalytic performance at low temperatures, high redox properties, and high adsorption capacity for the reaction gases (O₂ and styrene). Moreover, the catalytic performance of CeO₂–S was highly stable (132 h), and the particles were reusable. FTIR and in-situ DRIFTS results showed that the type of intermediates formed during the oxidation of styrene determined the CeO₂ catalytic stability, and the main intermediates were bidentate carbonate species that accumulated on the surface of deactivated CeO₂–S and were not thermally stable. Moreover, the soft carbon that also deposited on CeO₂–S during the reaction was easily decomposed at higher temperatures. The role of the oxygen vacancies on the CeO₂–S catalyst was further revealed by correlating the concentration of oxygen vacancies and the accumulation of coke on the catalyst surface.
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