Cubic Cesium Hydrogen Silicododecatungstate with Anisotropic Morphology and Polyoxometalate Vacancies Exhibiting Selective Water Sorption and Cation-Exchange Properties

详细信息    查看全文

• 作者：Yoshiyuki Ogasawara ; Sayaka Uchida ; Toshiaki Maruichi ; Ryo Ishikawa ; Naoya Shibata ; Yuichi Ikuhara ; Noritaka Mizuno
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：25
• 期：6
• 页码：905-911
• 全文大小：467K
• 年卷期：v.25,no.6(March 26, 2013)
• ISSN：1520-5002

文摘

A cesium hydrogen silicododecatungstate Cs_3.0H_0.3[SiW₁₂O₄₀]_0.83路3.0H₂O (CsSiW) with a cubic cell and anion ([SiW₁₂O₄₀]4鈥?/sup>) vacancies is synthesized, and the anion vacancies are utilized for selective water sorption and exchange of monovalent cations. Compound CsSiW consists of highly crystalline particles with a flat rhombic bipyramidal morphology, and the anisotropic morphology is reported for the first time among the cubic solid POM compounds. Due to the high crystallinity and flatness of CsSiW, direct atomic images (heavy cesium and tungsten atoms) are observed for the first time in solid POM compounds. The electron-microscopic images suggest that CsSiW grows through (i) formation of [Cs₃SiW₁₂O₄₀]鈭?/sup> followed by adsorption of Cs⁺, (ii) then parallel to the {110} plane, forming plates, and (iii) perpendicular to the {110} plane accompanied by the generation of anion vacancies. The mismatch between anion to cation site ratio (1:3) and cation to anion charge ratio (1:4) would be crucial for the anisotropic crystal growth and generation of anion vacancies.

Keywords:

cubic structure; polyoxometalate; anisotropic morphology; anion vacancy; water sorption; ion-exchange