Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
Jiangsu Laboratory of Advanced Functional Materials, School of Chemistry and Material Engineering, Changshu Institute of Technology, Changshu, 215500, China.
Nat Commun. 2017 Sep 18;8(1):581. doi: 10.1038/s41467-017-00603-7.
Facet engineering of oxide nanocrystals represents a powerful method for generating diverse properties for practical and innovative applications. Therefore, it is crucial to determine the nature of the exposed facets of oxides in order to develop the facet/morphology-property relationships and rationally design nanostructures with desired properties. Despite the extensive applications of electron microscopy for visualizing the facet structure of nanocrystals, the volumes sampled by such techniques are very small and may not be representative of the whole sample. Here, we develop a convenient O nuclear magnetic resonance (NMR) strategy to distinguish oxide nanocrystals exposing different facets. In combination with density functional theory calculations, we show that the oxygen ions on the exposed (001) and (101) facets of anatase titania nanocrystals have distinct O NMR shifts, which are sensitive to surface reconstruction and the nature of the steps on the surface. The results presented here open up methods for characterizing faceted nanocrystalline oxides and related materials.The exposed facets of oxide nanocrystals are key to their properties. Here, the authors use O solid-state NMR spectroscopy to discriminate between oxygen species on different facets of anatase titania nanocrystals, providing compelling evidence for the value of NMR spectroscopy in characterizing faceted oxides.
氧化物纳米晶体的晶面工程是一种产生多样化性质的有力方法，对于实际的创新应用具有重要意义。因此，确定氧化物暴露晶面的性质对于发展晶面/形态-性质关系以及合理设计具有所需性质的纳米结构至关重要。尽管电子显微镜在可视化纳米晶体的晶面结构方面得到了广泛应用，但这些技术所采样的体积非常小，可能无法代表整个样品。在这里，我们开发了一种简便的 O 核磁共振（NMR）策略来区分暴露不同晶面的氧化物纳米晶体。结合密度泛函理论计算，我们表明锐钛矿 TiO2 纳米晶体暴露的（001）和（101）晶面上的氧离子具有不同的 O NMR 位移，这对表面重构和表面台阶的性质敏感。这里呈现的结果为晶面纳米氧化物和相关材料的特性研究开辟了新的方法。氧化物纳米晶体的暴露晶面是其性质的关键。在这里，作者使用 O 固态 NMR 光谱学来区分锐钛矿 TiO2 纳米晶体不同晶面上的氧物种，为 NMR 光谱学在晶面氧化物特性研究中的价值提供了有力的证据。
