水热法制备SiO_2@Mn_2O_3球形纳米粒子

Synthesis of Spherical SiO_2@Mn_2O_3 Nanoparticles by Hydrothermal Method

以二氧化硅微球为模板,乙酸锰和尿素为反应物,在水热条件下合成了SiO_2@MnCO_3中间产物,经煅烧后获得SiO_2@Mn_2O_3。主要考察了尿素浓度、二氧化硅模板用量对中间产物形貌和结构的影响。利用热重分析仪(DSC/TG)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和氮气吸附脱附对产物进行了表征。实验结果表明:尿素浓度和二氧化硅模板的用量对产物形貌和结构有明显影响;产物煅烧前后形貌、结构变化不大,但是煅烧后产物的BET比表面积显著增大,孔径明显减小。

SiO2@MnCO3 nanoparticles have been successfully synthesized by calcination of SiO2@MnCO3 precursor that was obtained via hydrothermal method at 140 ℃ using manganese acetate and urea as the reactants,silicon dioxide as template.The as-prepared products were characterized by thermal analyzer（DSC/TG）,X-ray diffraction（XRD）,field-emission scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and N2 adsorption-desorption.The morphologies of the hydrothermal products changed significantly with different concentration of urea and different mass of silicon dioxide.The morphologies of precursor SiO2@MnCO3was sustained after thermal decomposition to SiO2@MnCO3 by calcination at 560℃,while the BET surface area of SiO2@MnCO3 increased dramatically.