【摘要】 以水玻璃为原料制备了3种不同粒径的纳米二氧化硅水分散液,滴加入锆酸四正丁酯异丙醇溶液,使水解的锆酸定向吸附至二氧化硅表面并缩聚为氧化锆从而形成氧化锆包覆的二氧化硅水溶胶。透射电子显微镜、电子能谱分析和不同微粒表面ζ电位与Gouy-Chapman模型计算表明:二氧化硅表面氧化锆的包覆率为57%。紫外可见光研究表明:该纳米微粒紫外吸收随粒径的增大有所下降,可见光的透过性也略有下降。经喷雾干燥成粉后,复合微粉的比表面积为135m2/g。XRD分析表明:有少量的ZrO2单斜晶型存在,600℃煅烧后,粉体比表面积100.5 m2/g,呈单斜晶型;1 300℃煅烧后,粉体比表面积为67.3 m2/g,为四方晶型结构。更多还原

【Abstract】 Three monodispersed,stable spherical silicas in nanosize were prepared from water glass.The zirconium n-tetrabutanoxide in isopropanol was added into the aqueous silica dispersion and hydrolysed to zirconic acid,and then directionally adsorbed and condensablely polymerized on the surface of the silica by control of pH and the concentration of the tetrabutyl zirconate.The results of TEM,EDS,ζ-potential and surface charge of nanoparticles in terms of Gouy-Chapman model show that the zirconia are coated onto the surface of silica nanoparticles,and the coverage is 57%.The UV-vis analysis indicates that ultraviolet absorption of the zirconia-coated silica dispersion is declined with increase of the nanoparticle size,and the visible transmittance of the dispersion is also lost slightly.The zirconia-coated silica powders are obtained by spray dryer,and the specific surface area of the powder is 135 m~2/g.The XRD patterns denote that there is a little monoclinic phase of the zirconia in the powder.After calcined at 600 ℃ and 1 300 ℃,the specific surface areas are 100.5 m~2/g and 67.3 m~2/g,and structures of the powder are monoclinic phase and tetragonal phase,respectively.更多还原