CeO₂ nanomaterials expose various crystal facets with distinct surface geometry, resulting in different surface reactivities and material behaviors that ultimately determine their performances and suitability for a wide range of applications. Here, we apply ¹⁷O solid-state nuclear magnetic resonance (NMR) to follow the facet transformation of CeO₂ at increased temperatures, observing a transition from (100) to (110) and finally to the more stable (111), based on the characteristic NMR shifts associated with the unique surface structure of each facet. In addition, we explore the effects of Pt ions on the conversion of different facets, which are found to promote the formation of the thermally stable (111) facet. Furthermore, ¹⁷O solid-state NMR provides a semiquantitative method for measuring the fractions of exposed facets. This work offers new insights and a more comprehensive understanding of crystal facet structures, and the new approach can be readily extended to study the facets of other oxide-based materials.

中文翻译：

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通过 17O 固态核磁共振跟踪 CeO2 的刻面转变


CeO₂ 纳米材料暴露出具有不同表面几何形状的各种晶体刻面，导致不同的表面反应性和材料行为，最终决定其性能和广泛应用的适用性。在这里，我们应用 ¹⁷O 固态核磁共振 （NMR） 来跟踪 CeO₂ 在高温下的刻面转变，根据与每个刻面的独特表面结构相关的特征 NMR 偏移，观察从 （100） 到 （110） 再到更稳定的 （111） 的转变。此外，我们还探讨了 Pt 离子对不同刻面转化的影响，发现这些影响会促进热稳定 （111） 刻面的形成。此外，¹⁷O 固体 NMR 提供了一种半定量方法来测量暴露刻面的分数。这项工作为晶体刻面结构提供了新的见解和更全面的理解，并且新方法可以很容易地扩展到研究其他氧化物基材料的刻面。