Compressibility and Structural Stability of Nanocrystalline TiO2 Anatase Synthesized from Freeze-Dried Precursors

详细信息    查看全文

• 作者：Catalin Popescu ; Juan Angel Sans ; Daniel Errandonea ; Alfredo Segura ; Regina Villanueva ; Fernando Sapi帽a
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：November 3, 2014
• 年：2014
• 卷：53
• 期：21
• 页码：11598-11603
• 全文大小：356K
• ISSN：1520-510X

文摘

The high-pressure structural behavior of 30 nm nanoparticles of anatase TiO₂ was studied under hydrostatic and quasi-hydrostatic conditions up to 25 GPa. We found that the structural sequence is not sensitive to the use of different pressure transmitting media. Anatase-type nanoparticles exhibit a phase transition beyond 12 GPa toward a baddeleyite-type structure. Under decompression this phase transition is irreversible, and a metastable columbite-type structure is recovered at ambient conditions. The bulk modulus of anatase-type nanoparticles was determined confirming that nanoparticles of TiO₂ are more compressible than bulk TiO₂. Similar conclusions were obtained after the determination of the bulk modulus of baddeleyite-type nanoparticles. Furthermore, axial compressibilities and the effect of pressure in atomic positions, bond distances, and bond angles are determined. Finally, a possible physical explanation for the destabilization of anatase under pressure is proposed based upon this information.