Solid-Solution Nanoparticles: Use of a Nonhydrolytic Sol-Gel Synthesis To Prepare HfO2 and HfxZr1-xO2 Nanocry

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• 作者：Jing Tang ; Jason Fabbri ; Richard D. Robinson ; Yimei Zhu ; Irving P. Herman ; Michael L. Steigerwald ; and Louis E. Brus
• 刊名：Chemistry of Materials
• 出版年：2004
• 出版时间：April 6, 2004
• 年：2004
• 卷：16
• 期：7
• 页码：1336 - 1342
• 全文大小：350K
• 年卷期：v.16,no.7(April 6, 2004)
• ISSN：1520-5002

文摘

A nonhydrolytic sol-gel process closely following that of Hyeon et al. for the synthesis ofZrO₂ nanocrystals (J. Am. Chem. Soc. 2003, 125, 6553-6557) was used to synthesize highlycrystalline and monodisperse HfO₂ nanoparticles. Reactions of hafnium isopropoxide withhafnium halides at high temperature in a strongly coordinating solvent yield nanometer-sized particles of HfO₂. The size, shape, and crystalline phase of the hafnia particles dependon both the reaction temperature and the halide. The nonhydrolytic cross-condensationmethod was also extended to the binary metal oxides nanocrystals, i.e., HfO₂-ZrO₂, ZrO₂-TiO₂, and HfO₂-TiO₂. Efforts to prepare nanocrystals of Hf_xZr_1-xO₂ over a wide range of xwere successful; however, this method could not be used to prepare either Zr_xTi_1-xO₂ orHf_xTi_1-xO₂. In conjunction with X-ray powder diffraction and high-resolution transmissionelectron microscopy, Raman spectroscopy identifies the structural phase of the nanocrystalsand also proves the formation of the Hf-Zr solid solution nanoparticles via the cross-condensation method. In the case of Hf_xZr_1-xO₂, for x < 0.5, highly monodisperse, roughlyspherical particles of tetragonal Hf_xZr_1-xO₂ were formed, while for x > 0.5, small nanorodsof the monoclinic phase of the binary oxide were obtained.