pH值对CeO2/SiO2纳米复合磨粒分散性的影响

Effect of pH value on dispersity of CeO2/SiO2 composite nanoparticles

以胶体SiO2溶液作硅源,采用均相沉淀工艺制备壳–核结构完整的CeO2/SiO2纳米复合磨粒。采用X射线衍射仪和透射电子显微镜对复合磨粒样品进行物相组成分析和微观形貌观察;通过粒径分布、Zeta电位分析,研究水相分散系中pH值对CeO2/SiO2复合磨粒分散性的影响。结果表明:所制备的CeO2/SiO2复合磨粒为壳–核包覆结构完整的纳米微球,粒径约110 nm,内核为无定形SiO2,壳层为立方萤石型CeO2;CeO2/SiO2复合磨粒的等电位点pH值约为5,其值由SiO2等电位点向CeO2等电位点明显偏移。CeO2/SiO2复合磨粒在酸性水相介质中分散性差,容易出现严重的团聚现象;而在碱性环境下,CeO2/SiO2复合磨粒分散性良好。

CeO2/SiO2 composite nanoparticles with complete core-shell structure were prepared through homogeneous precipitation method using commercial silica sol as silicon resource.The phase composition and nanotopography of the as-prepared particles were characterized by X-ray diffraction(XRD)and transmission electron microscope(TEM),respectively.The effect of pH value on the dispersity of CeO2/SiO2 composite nanoparticles in water suspension was studied by the analysis of size distribution and Zeta potential.The results indicated that the as-prepared composite nanoparticles possessed a complete core-shell structure which composed by amorphous silica core and cubic fluorite ceria shell.The particle size was about 110 nm.The equipotential point of CeO2/SiO2 composite nanoparticles was about pH5,and its value was significantly shifted from the equipotential point of SiO2 to the equipotential point of CeO2.The as-prepared composite nanoparticles agglomerated easily under the acidic condition,while dispersed well under the alkaline condition.