In this paper, the effect of the hierarchical arrangement of nanocrystallites on CO oxidation and soot combustion activity has been investigated. Hierarchically structured star-shaped particles (HS stars) were compared with microemulsion-derived, loosely arranged nanoparticles (NPs). Star-like Ce_0.9REE_0.1O_1.95 mixed oxides were synthesized by oxidative thermolysis of Ce_0.9REE_0.1(HCOO)₃ mixed formates. The study of the synthesis, structure and catalytic activity of the porous, star-like ceria-based mixed oxides was presented for the first time. It was shown that each level of the hierarchical structure of the star-like mixed oxides has its own functionality and it is vulnerable to modifications. In-depth characterization of as-synthesized ceria allowed determination of the relationship between the hierarchically structured nature of the material and its catalytic activity in CO oxidation and soot combustion. It was concluded that the presence of the 3D structure composed of ceria nanocrystals significantly improves the stability and catalytic activity of the star-like material in comparison to the nanopowder. Moreover, introduction of the trivalent RE ion into the ceria structure led to further improvement of the CO oxidation performance. Finally, the key–lock catalysis concept was applied to explain the enhanced activity of the hierarchically structured star-shaped ceria particles as a catalyst in the soot combustion process in comparison to nanocrystalline CeO₂.

中文翻译：

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Ce0.9REE0.1O1.95多孔氧化物混合体各级层次结构在催化活性中的作用。

本文研究了纳米微晶的层级排列对CO氧化和烟so燃烧活性的影响。将层次结构的星形颗粒（HS星形）与微乳液衍生的，松散排列的纳米颗粒（NP）进行了比较。通过对Ce _0.9 REE _0.1（HCOO）_3的氧化热解合成了星形Ce _0.9 REE _0.1 O _1.95混合氧化物混合格式。首次提出了多孔，星形二氧化铈基混合氧化物的合成，结构和催化活性的研究。结果表明，星形混合氧化物的分层结构的每个级别都有其自身的功能，并且容易受到修饰。合成二氧化铈的深入表征可以确定材料的分层结构性质与其在CO氧化和烟灰燃烧中的催化活性之间的关系。结论是，与纳米粉末相比，由二氧化铈纳米晶体组成的3D结构的存在显着改善了星形材料的稳定性和催化活性。此外，将三价RE离子引入二氧化铈结构导致了CO氧化性能的进一步提高。最后，采用了键锁催化概念来解释与纳米CeO相比，分层结构的星形二氧化铈颗粒在烟灰燃烧过程中作为催化剂的增强活性。₂。