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Preparation and Characterization of ZrO_2 Nanoparticles Capped by Trioctylphosphine Oxide (TOPO) 认领 引用 被引量:1
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作者 马剑琪 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第4期611-614,共4页
Monodisperse ZrO2 nanoparticles capped by trioctylphosphine oxide (TOPO) were prepared in non-aqueous solvent using in-situ synthesis method. Transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray ... Monodisperse ZrO2 nanoparticles capped by trioctylphosphine oxide (TOPO) were prepared in non-aqueous solvent using in-situ synthesis method. Transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectrometer(XPS), Fourier transformation infrared spectroscopy (FTIR), and thermogravimetric analysis(TGA) were adopted to characterize and investigate the size, structure, composition, and the binding manners between organic capping agent TOPO and inorganic ZrO2 nanocores of the as-prepared nanoparticles. In addition, the nanoparticles were also studied to determine their solubility and relative stability. The experimental results show that the prepared nanoparticles contain about 25% organic capping shell TOPO, 75% inorganic ZrO2 nanocores, and can be easily dissolved and be stably disersed in non-polar organic solvents. 展开更多
关键词 ZrO2 nanoparticles trioctylphosphine oxide (TOPO) monodisperse solubility
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Synthesis, Characterization and Thermal Stability of CeO_2 Stabilized ZrO_2 Ultra Fine Nanoparticles Via a Sol-gel Route 认领 引用
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作者 贾铁昆 闵志宇 +4 位作者 LONG Fei LIU Ming FU Fang WANG Xiaofeng SUN Guang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第6期1245-1249,共5页
CeO_2 stabilized ZrO_2 ultra fine nanoparticles were successfully synthesized via a simple and effective sol-gel synthetic approach by using zirconylchloride octahydrate, cerium nitrate hexahydrate, and citric acid as... CeO_2 stabilized ZrO_2 ultra fine nanoparticles were successfully synthesized via a simple and effective sol-gel synthetic approach by using zirconylchloride octahydrate, cerium nitrate hexahydrate, and citric acid as starting materials. A series of techniques, including X-ray diffraction(XRD), thermogravimetry(TG), differential scanning calorimetry(DSC), Fourier transform infrared spectroscopy(FTIR), transmission electron microscopy(TEM), and N_2-sorption analysis, were used to characterize the structure and morphology of the asprepared samples. XRD studies indicate that the as-synthesized sample is of well crystallized tetragonal phase of CeO_2 stabilized ZrO_2 with high purity. TEM images show that the as-synthesized sample is composed of a large number of fine dispersive nanoparticles with an average size about 10 nm. The as-synthesized tetragonal CeO_2 stabilized ZrO_2 sample was heated at different temperatures in order to evaluate its thermal stability. The exprimental results reveal that the as-synthesized tetragonal CeO_2 stabilized ZrO_2 sample exhibits excellent stability without the occurrence of phase transformation. 展开更多
关键词 CeO2 stabilized ZrO2 nanoparticles sol-gel tetragonal phase thermal stability
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Zr(Ⅳ) surface sites determine CH3OH formation rate on Cu/ZrO2/SiO2-CO2 hydrogenation catalysts 认领 引用 被引量:3
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作者 Erwin Lam Kim Larmier +3 位作者 Shohei Tada Patrick Wolf Olga V. Safonova Christophe Copéret 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第11期1741-1748,共8页
Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carri... Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(Ⅳ) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(Ⅳ) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(Ⅳ) surface sites that stabilizes reaction intermediates. 展开更多
关键词 CO2 hydrogenation ZrO2/SiO2 supported Cu nanoparticles Lewis acidic surface sites In situ X-ray absorption spectroscopy
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