In situ FT-IR study on the homogeneous nucleation of nanoparticles of titanium oxides from highly supersaturated vapor
In situ FT-IR study on the homogeneous nucleation of nanoparticles of titanium oxides from highly supersaturated vapor
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DOI：
10.1016/j.jcrysgro.2016.06.036
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发表时间：
2016-09-15
影响因子：
1.8
通讯作者：
Yamazaki, Tomoya
中科院分区：
文献类型：
--
作者：
Ishizuka, Shinnosuke;Kimura, Yuki;Yamazaki, Tomoya
通过原位傅里叶变换红外光谱和通过透射电子显微镜（TEM）观察所得纳米颗粒，研究了通过高度过饱和蒸气均匀成核形成氧化钛纳米颗粒。钛金属在专门设计的室中在氧气和氩气气氛下热蒸发。纳米颗粒在氧化气体气氛中自由飞行时成核并随后生长。新生的氧化钛纳米粒子在 10-20 μm 处显示出宽的红外吸收带。随后，冷却的纳米颗粒在 12.8 μm 处显示出尖锐的锐钛矿晶体特征。 TEM 观察显示球形锐钛矿纳米粒子的形成。红外光谱演变表明，钛氧化物以亚稳态液滴形式成核，并且结晶是通过过冷液滴的二次成核进行的。这表明氧化钛纳米粒子的历史，例如它们成核后经历的温度和氧化，决定了它们的多晶型。 (C) 2016 Elsevier B.V. 保留所有权利。
The formation of nanoparticles of titanium oxides by homogeneous nucleation from highly supersaturated vapors was investigated by in situ Fourier transform IR spectroscopy and by observation of the resulting nanoparticles by transmission electron microscopy (TEM). Titanium metal was thermally evaporated in a specially designed chamber under a gaseous atmosphere of oxygen and argon. Nano particles nucleated and subsequently grew as they flew freely through the oxidizing gas atmosphere. Nascent nanoparticles of titanium oxides showed a broad IR absorption band at 10-20 mu m. Subsequently, the cooled nanoparticles showed a sharp crystalline anatase feature at 12.8 mu m. TEM observations showed the formation of spherical anatase nanoparticles. The IR spectral evolution showed that the titanium oxides nucleated as metastable liquid droplets, and that crystallization proceeded through secondary nucleation from the supercooled liquid droplets. This suggests that history of the titanium oxide nanoparticles, such as the temperature and oxidation that they experience after nucleation, determines their polymorphic form. (C) 2016 Elsevier B.V. All rights reserved.