Synthesis and Characterization of Nanofibrous Sodium Manganese Oxide with a 2 × 4 Tunnel Structure
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- 作者：Guan-Guang Xia ; Wei Tong ; Elaine N. Tolentino ; Nian-Gao Duan ; Stephanie L. Brock ; Jin-Yun Wang ; Steven L. Suib ; and Thorsten Ressler
- 刊名：Chemistry of Materials
- 出版年：2001
- 出版时间：May 2001
- 年：2001
- 卷：13
- 期：5
- 页码：1585 - 1592
- 全文大小：209K
- 年卷期：v.13,no.5(May 2001)
- ISSN：1520-5002
文摘
Sodium manganese oxide octahedral molecular sieves with a 2 × 4 tunnel structure (Na-2× 4) have been hydrothermally synthesized from Na-birnessite materials at low temperatures and pressures. The synthetic template materials, the pH value of the medium, andthe autoclaved temperature are critical in the synthesis. Sodium salts, such as NaCl, NaNO3,and Na2SO4, are good templates for Na-2 × 4. In strong basic solution or below 160 
C,Na-birnessite does not transform to the Na-2 × 4 structure. TEM images show thesynthesized Na-2 × 4 is made up of thin slablike single crystals elongated along the b axis.The formula of Na-2 × 4 can be written as Na0.33M
M
O2·xH2O, and it is monoclinicwith space group C2/m. The unit cell parameters (a, b, c, and 
) for Na-2 × 4 are 14.434(5)Å, 2.849(7) Å, 23.976(6) Å, and 98.18, respectively. These data for Na-2 × 4 are slightlydifferent from the data for Rb-2 × 4 synthesized under high pressure and high temperature,which were reported by Rziha et al. (Eur. J. Miner. 1996, 8, 1155-1161). The surface areaof Na-2 × 4 is about 57 m2/g. Na-2 × 4 materials are thermally stable up to 450 C asindicated by TGA and TPD data.
C,Na-birnessite does not transform to the Na-2 × 4 structure. TEM images show thesynthesized Na-2 × 4 is made up of thin slablike single crystals elongated along the b axis.The formula of Na-2 × 4 can be written as Na0.33MMO2·xH2O, and it is monoclinicwith space group C2/m. The unit cell parameters (a, b, c, and ) for Na-2 × 4 are 14.434(5)Å, 2.849(7) Å, 23.976(6) Å, and 98.18, respectively. These data for Na-2 × 4 are slightlydifferent from the data for Rb-2 × 4 synthesized under high pressure and high temperature,which were reported by Rziha et al. (Eur. J. Miner. 1996, 8, 1155-1161). The surface areaof Na-2 × 4 is about 57 m2/g. Na-2 × 4 materials are thermally stable up to 450 C asindicated by TGA and TPD data.