纳米二氧化铈上活性氧物种的氧空穴团簇捕集位点

二氧化铈（CeO2）是一种性能优异的催化材料，已广泛应用于大气污染物的控制，这与其优异的储放氧性能即氧空穴的形成、消除相关；研究氧空穴在上氧物种的形成及活性对设计高效的铈基催化剂具有重要意义。X射线光电子能谱(XPS)、正电子湮没寿命谱(PAS)、氢气-程序升温还原(H2-TPR)研究结果表明，不同形貌的CeO2纳米材料上氧空穴团簇大小、相对强度、单位面积上Ce3+浓度的乘积与高活性氧物种的量之间呈线性相关，这一定量关系揭示氧空穴团簇是CeO2纳米材料上活性氧物种的捕集位点，对认识CeO2催化作用机制具有理论指导意义。

Oxygen vacancy clusters as trapping sites for active oxygen species on nanoceria

Ceria (CeO2) as an efficient catalytic material, has been extensively investigated in air pollution control, which largely originates from its remarkable ability to release and store oxygen via the formation and healing of oxygen vacancies, respectively. Understanding of oxygen vacancies in creating and supplying of active oxygen species is therefore fundamental for designing ceria based catalysts with high performance. By applying complementary techniques of X-ray photoelectron spectroscopy (XPS), positron annihilation spectroscopy (PAS), and H2 temperature-programmed reduction (H2-TPR), herein, an excellent linear correlation between the contribution of oxygen vacancy clusters (size and relative intensity of oxygen vacancy clusters, and concentration of Ce3+ on unit area) and the amount of the most easily reducible surface oxygen was first revealed on nanoceria with different shapes. The finding indicates that oxygen vacancy clusters may serve as trapping sites for the active surface oxygen on nanoceria, may also be fundamental for revealing the intrinsic role of ceria in catalysis.