Liu Fang, Dong Zhaohui, Liu Lijia
Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123, People's Republic of China.
J Phys Condens Matter. 2019 Oct 2;31(39):395403. doi: 10.1088/1361-648X/ab2d17. Epub 2019 Jun 26.
Nanostructured anatase TiO undergoes pressure-induced phase transformation, and the transformation sequence is significantly different from the bulk counterpart. The size and the morphology are found both playing a critical role in the phase transformation behavior. In this work, we prepare anatase TiO microspheres using a hydrothermal method. By controlling the reaction time, hollow and solid spheres of similar diameters are prepared. TEM and XRD analysis reveals that these microspheres are aggregates of anatase nanocrystalline of size between 15-16 nm. The phase transformation behaviour under high temperature is examined in situ using both Raman spectroscopy and synchrotron x-ray diffraction. We find that although both solid and hollow spheres are micron-sized, they undergo phase transformation sequence similar to nanomaterials with size of several tens of nanometers. Hollow spheres exhibit a higher compressibility than the solid spheres. A detailed analysis based on the formation mechanism of the spheres is performed to explain the unique phase transformation behavior of these materials.
纳米结构的锐钛矿型二氧化钛会发生压力诱导相变，其相变顺序与块状材料有显著不同。研究发现尺寸和形态在相变行为中都起着关键作用。在本工作中，我们采用水热法制备了锐钛矿型二氧化钛微球。通过控制反应时间，制备出了直径相似的空心和实心微球。透射电子显微镜（TEM）和X射线衍射（XRD）分析表明，这些微球是尺寸在15 - 16纳米之间的锐钛矿纳米晶体的聚集体。利用拉曼光谱和同步辐射X射线衍射对高温下的相变行为进行了原位研究。我们发现，尽管实心和空心微球都是微米级尺寸，但它们经历的相变顺序与几十纳米尺寸的纳米材料相似。空心球比实心球表现出更高的可压缩性。基于微球形成机制进行了详细分析，以解释这些材料独特的相变行为。
