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Distinguishing faceted oxide nanocrystals with ¹⁷O solid-state NMR spectroscopy.

ABSTRACT: 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 ¹⁷O 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 ¹⁷O 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 ¹⁷O 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.

SUBMITTER: Li Y

PROVIDER: S-EPMC5603560 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Distinguishing faceted oxide nanocrystals with <sup>17</sup>O solid-state NMR spectroscopy.

Li Yuhong Y Wu Xin-Ping XP Jiang Ningxin N Lin Ming M Shen Li L Sun Haicheng H Wang Yongzheng Y Wang Meng M Ke Xiaokang X Yu Zhiwu Z Gao Fei F Dong Lin L Guo Xuefeng X Hou Wenhua W Ding Weiping W Gong Xue-Qing XQ Grey Clare P CP Peng Luming L

Nature communications 20170918 1

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 techniqu ...[more]

PMID: 28924155

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Project description:The spectroscopic study of oxygen, a vital element in materials, physical, and life sciences, is of tremendous fundamental and practical importance. 17O solid-state NMR (SSNMR) spectroscopy has evolved into an ideal site-specific characterization tool, furnishing valuable information on the local geometric and bonding environments about chemically distinct and, in some favorable cases, crystallographically inequivalent oxygen sites. However, 17O is a challenging nucleus to study via SSNMR, as it suffers from low sensitivity and resolution, owing to the quadrupolar interaction and low 17O natural abundance. Herein, we report a significant advance in 17O SSNMR spectroscopy. 17O isotopic enrichment and the use of an ultrahigh 35.2 T magnetic field have unlocked the identification of many inequivalent carboxylate oxygen sites in the as-made and activated phases of the metal-organic framework (MOF) α-Mg3(HCOO)6. The subtle 17O spectral differences between the as-made and activated phases yield detailed information about host-guest interactions, including insight into nonconventional O···H-C hydrogen bonding. Such weak interactions often play key roles in the applications of MOFs, such as gas adsorption and biomedicine, and are usually difficult to study via other characterization routes. The power of performing 17O SSNMR experiments at an ultrahigh magnetic field of 35.2 T for MOF characterization is further demonstrated by examining activation of the MIL-53(Al) MOF. The sensitivity and resolution enhanced at 35.2 T allows partially and fully activated MIL-53(Al) to be unambiguously distinguished and also permits several oxygen environments in the partially activated phase to be tentatively identified. This demonstration of the very high resolution of 17O SSNMR recorded at the highest magnetic field accessible to chemists to date illustrates how a broad variety of scientists can now study oxygen-containing materials and obtain previously inaccessible fine structural information.

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Distinguishing faceted oxide nanocrystals with ¹⁷O solid-state NMR spectroscopy.

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Distinguishing faceted oxide nanocrystals with <sup>17</sup>O solid-state NMR spectroscopy.

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Distinguishing faceted oxide nanocrystals with 17O solid-state NMR spectroscopy.

Publications

Distinguishing faceted oxide nanocrystals with <sup>17</sup>O solid-state NMR spectroscopy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Distinguishing faceted oxide nanocrystals with ¹⁷O solid-state NMR spectroscopy.