Physical Sciences and Mathematics Commons^™

High Pressure Studies Of Nanostructured Tio2 And Li4ti5o12 Using Raman Spectroscopy And Synchrotron X-Ray Radiation, Fengping Xiao

Electronic Thesis and Dissertation Repository

Nanomaterials have been extensively studied due to their distinctive properties such as surface effect, small-size effect and quantum size effect. In recent year, investigations of the structural and phase transformations of nanomaterials under high pressure are receiving increasing attentions. In addition to composition and synthetic routes, pressure provides a clean way to adjust interatomic distance and hence affect the crystal structure and thus properties of the nanostructured materials.Two nanomaterials (i.e. TiO₂ and Li₄Ti₅O₁₂) with different morphologies are studied in this thesis.

In part I, the high-pressure behaviours of four hydrothermal synthesized 1D rutile …

In Situ High-Pressure Study Of Metal-Organic Frameworks And Their Performance For Co2 Storage Probed By Vibrational Spectroscopy, Yue Hu

Electronic Thesis and Dissertation Repository

Metal-organic frameworks (MOFs) are an important class of porous materials, owing to their potential applications in a variety of areas, including gas storage, molecular separations, catalysis, sensors and so on. Most importantly, their extraordinary surface areas, tunable pore properties and potential for industrial scale production have made MOFs a promising material for clean energy applications, such as CO₂ storage. The chemical and mechanical stabilities of MOFs play a crucial role in their CO₂ storage performance, which require extreme loading pressures that are far beyond ambient pressure at times. Application of high external pressure (e.g., in gigapascal range) on …

High Pressure And High Temperature Study Of Magnesiochromite And Its Geophysical Implications, N M Tauhid Belal Khan

Electronic Thesis and Dissertation Repository

Magnesiochromite (MgCr₂O₄) is commonly found in the Earth’s crust, upper mantle, meteorites, and possibly in lunar crust. Synchrotron X-ray diffraction measurements of MgCr₂O₄ using double-sided laser heating diamond anvil cell showed the dissociation of MgCr₂O₄ to Cr₂O₃+MgO at ~15 GPa and to Mg₂Cr₂O₅+Cr₂O₃ below and above ~1500 K, respectively. At above 20 GPa, only a single phase CaTi₂O₄-type structure of MgCr₂O₄ was observed at 1400-2000 K. Fitting the pressure-volume data …