SiO_2@Fe_2O_3核-壳结构催化剂的制备及表征

Preparation and characterization of SiO_2@Fe_2O_3 core-shell catalysts

采用优化的Stber法制备了平均粒径为230 nm的单分散球形SiO2颗粒,并以此为内核,通过水解沉积法制备了不同壳层厚度的核-壳结构SiO2@Fe2O3催化剂。采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、N2物理吸附和X射线衍射分析（XRD）等手段对催化剂进行表征,探讨了不同制备条件对SiO2@Fe2O3催化剂形貌的影响。结果表明,通过水解沉积法制备的SiO2@Fe2O3催化剂具有明显的核-壳结构,并且保持了原始SiO2核的球形形貌,Fe2O3纳米粒子通过-OH的氢键作用连接在SiO2表面,形成了2~10 nm厚的Fe2O3均匀连续包覆层。

The monodisperse SiO2 microspheres with average diameter of 230 nm made by optimized Stber method were used as core to prepare core-shell structure SiO2@ Fe2O3 catalysts with different shell thickness through hydrolysis precipitation. Scanning electron microscopy（ SEM）, transmission electron microscopy（TEM）,N2 physical adsorption and X-ray diffraction（ XRD） were used to characterize the size,structure and morphology of catalysts and the effects of different preparation condition on morphology were discussed. The characterization results indicate that SiO2@ Fe2O3 catalysts possess obvious core-shell structure and the spherical morphology of catalyst is kept. Iron oxide nanoparticles are attached to the silica surface through hydroxyl-bond and a 2 ~ 10 nm thick dense shell is formed.