Among the factors affecting ceria activity, the defectiveness plays a key role in the case of CO oxidation. In this study, its connection with the catalytic performance was investigated via in-situ Raman spectroscopy on nanostructured pure and Cu/Mn-doped ceria, monitoring the defect sites and surface species evolution during the reaction. The accumulation of polyene-like chains, formed through CO dissociative adsorption at the catalyst surface, was observed and their disappearance was related to the catalyst light-off temperature. Moreover, the doped samples exhibited a rise of the Raman bands associated to defects after the tests, consequence of the structural rearrangements occurring during CO oxidation. Indeed, in-situ Raman measurements during reduction (CO/N₂) and oxidation cycles at 400 °C evidenced the formation of oxygen vacancy clusters in reducing atmosphere, which could reorganize not only in O₂ but also upon a temperature decrease, forming isolated vacancies and then evolving in Frenkel and extrinsic oxidized dopant-containing sites when exposed to oxygen.

在影响二氧化铈活性的因素中，缺陷在CO氧化的情况下起关键作用。在这项研究中，通过原位拉曼光谱对纳米结构的纯铜和锰/锰掺杂的二氧化铈进行了研究，研究了其与催化性能的关系，监测了反应过程中的缺陷部位和表面物种的演变。观察到通过CO解离吸附在催化剂表面形成的多烯状链的积累，其消失与催化剂起燃温度有关。此外，测试后，掺杂样品在缺陷处表现出与缺陷相关的拉曼能带上升，这是在CO氧化过程中发生结构重排的结果。实际上，还原过程中的原位拉曼测量（CO / N ₂）和400°C的氧化循环证明还原性气氛中氧空位簇的形成，不仅可以在O _2中重组，而且在温度降低时也可以重组，形成孤立的空位，然后在Frenkel和外部氧化的含掺杂位点处演化暴露在氧气中。