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Updated: Mar 7, 2026
Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks
Published on: February 10, 2023
Synthesis of ε-Keggin-Type Cobaltomolybdate-Based 3D Framework Material and Characterization Using Atomic-Scale
Takumi Igarashi1, Zhenxin Zhang2, Terufumi Haioka1
1Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University , 1-4-1 Kagamiyama, Higashi Hiroshima 739-8527, Japan.
Abstract:
We describe the preparation of ε-Keggin-type cobaltomolybdate-based 3D frameworks with sodium cations, NaH9[ε-CoIIMoV8MoVI4O40CoII2], and their characterization by high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy. Atomic-scale HAADF-STEM images of ε-Keggin compounds were obtained for the first time, and positions of Mo and Co were confirmed. Furthermore, clear evidence of the presence of a CoO4 tetrahedron was obtained by X-ray absorption near-edge structure (XANES) analysis. Their characterization clearly revealed that ε-Keggin-type cobaltomolybdate units, [ε-CoMo12O40]n-, constructed by a central CoIIO4 tetrahedron and 12 surrounding MoO6 octahedra, are linked with CoII to form 3D frameworks.
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