High-pressure Induced Phase Transition Of In₂O₃ And Synthesis Of ZnO And Cu₂O/Cu Nanocrystals

In this paper, By using thermal decomposition method,6.0 nm In2O3 nanoparticles were synthesized. The as-prepared In2O3 sample and bulk In2O3 were investigated by in situ high-pressure synchrotron radiation x-ray diffraction measurements at ambient temperature. It was found that nano-sized and bulk samples began to transform from cubic into hexagonal structure at about 15-25 GPa, and extended up to 40 GPa. For the nanoparticles, both cubic and hexagonal phases remained after pressure release. Below the onset transition pressure, the nano-sized samples were harder to compress with a larger bulk modulus of 296.06 GPa than the bulk samples with a bulk modulus of 178.87 GPa.In addition, the synthesis of transition metal oxide nanocrystals was studied:By the reaction between ZnSO4·7H2O and NaOH, and adding sodium dodecyl sulfat (SDS) as surfactant, a kind of three-dimensional (3D) ZnO nanocrystals were prepared. The nanocrystals exhibited a pomegranate-like morphology with four or six symmetric petals surrounding a spindle. The formation of this structure involved an initial growth to form nanorods and a secondary assembly process. The nanorods grew along [0001] direction due to the basic solution and the SDS additives contribute to the spindle-petals morphology. The as-synthesized samples showed strong UV emission and a wide green emission at room temperature, and exhibit stable electrochemical property as anode materials in rechargeable lithium-ion batteries. By using Cu(acac)2 as precursor, ethylene glyeol (EG) as solvent and PVP as reductant, Cu nanocubes were synthesized. Surface of these cubes were easy to be oxidized into Cu2O. By controlling time, pure Cu, Cu2O coated Cu and pure Cu2O were synthesized. The exsitance of Cu had little influnce in the performances of anodes in lithium-ion batteries.