具有介孔结构的Co/SiO2空心球的制备及其催化性能研究

摘要

Using silica as template, mesoporous cobalt silicate hollow spheres were synthesized by sacrificial template reaction.Their structures and morphologies were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and temperature procedure reduction (TPR).Their reduction law was groped and catalytic performance of Co/SiO2 on nitrobenzene hydrogenation was studied.The results indicate that the structures of cobalt silicate are hollow spheres under 1 h at 180℃.Co/SiO2 hollow spheres are obtained after reduction of cobalt silicate hollow spheres within 5 h under 800℃ with less specific surface area and bigger pore size than before reduction.But the hollow spheres before and after reduction still possess the similar hollow spheres.Using Co/SiO2 hollow spheres used as catalyst on conversion of nitrobenzene, the conversion rate reaches 56% within 1 h, about 14% higher than that of using commercial Raney Ni.%以二氧化硅为模板,采用牺牲模板法制备具有介孔结构的碱式硅酸钴空心球.采用扫描电子显微镜(SEM),透射电子显微镜(TEM)、X射线衍射(XRD)、氮气吸脱附曲线(BET)和程序升温还原(TPR)等方法,对样品的结构和形貌作了表征.探索了碱式硅酸钴空心球的还原规律,研究了Co/SiO2作催化剂的催化性能.结果表明,180℃下反应1 h时,碱式硅酸钴即为空心球结构;在800℃氢气气氛中反应5 h,碱式硅酸钴完全被还原为Co/SiO2,还原前后仍为空心球结构,比表面积和孔容均有所减小,孔径增大.以Co/SiO2空心球做催化剂进行硝基苯加氢催化,1 h后硝基苯的转化率为56%,比商用Raney Ni提高约14%.