Influence of volatile chlorides on the molten salt synthesis of ternary oxide nanorods and nanoparticles.
Influence of volatile chlorides on the molten salt synthesis of ternary oxide nanorods and nanoparticles.
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DOI：
10.1021/ic702207a
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发表时间：
2008-02
影响因子：
4.6
通讯作者：
Per Martin Rørvik;Tone Lyngdal;R. Saeterli;A. V. van Helvoort;R. Holmestad;T. Grande;M. Einarsrud
中科院分区：
文献类型：
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作者：
Per Martin Rørvik;Tone Lyngdal;R. Saeterli;A. V. van Helvoort;R. Holmestad;T. Grande;M. Einarsrud
先前报道的熔盐合成路线产生了BaTiO3， PbTiO3和Na2Ti6O13纳米棒，重新研究了挥发性氯化物的作用。将含有钡（或铅）和钛的前驱体混合物在760℃和820℃NaCl存在下退火，主要产物分别是等长纳米晶BaTiO3和PbTiO3。纳米棒也被检测到，但电子衍射显示两种不同体系的纳米棒的组成分别是BaTi2O5/BaTi5O11和Na2Ti6O13，这与之前的研究相矛盾。结果表明，NaCl与BaO （PbO）反应导致挥发性BaCl2 （PbCl2）的损失，富钛纳米棒的形成和优先生长取代了目标相BaTiO3（或PbTiO3）。因此，熔盐合成路线不一定如先前报道的那样产生目标三元氧化物的纳米棒。此外，在一个特殊的实验装置中，NaCl和前驱体物理分离，证明了NaCl(g)对低于NaCl熔点的纳米棒生长的重要性。
A molten salt synthesis route, previously reported to yield BaTiO3, PbTiO3, and Na2Ti6O13 nanorods, has been re-examined to elucidate the role of volatile chlorides. A precursor mixture containing barium (or lead) and titanium was annealed in the presence of NaCl at 760 or 820 degrees C. The main products were respectively isometric nanocrystalline BaTiO3 and PbTiO3. Nanorods were also detected, but electron diffraction revealed that the composition of the nanorods was respectively BaTi2O5/BaTi5O11 and Na2Ti6O13 for the two different systems, in contradiction to the previous studies. It was shown that NaCl reacted with BaO (PbO) resulting in loss of volatile BaCl2 (PbCl2) and formation and preferential growth of titanium oxide-rich nanorods instead of the target phase BaTiO3 (or PbTiO3). The molten salt synthesis route may therefore not necessarily yield nanorods of the target ternary oxide as reported previously. In addition, the importance of NaCl(g) for the growth of nanorods below the melting point of NaCl was demonstrated in a special experimental setup, where NaCl and the precursors were physically separated.