双金属催化剂Ni-Co/SiO2空心球的可控制备及催化性能

以二氧化硅为模板, 采用牺牲模板/界面反应法制备具有介孔结构的碱式硅酸镍钴空心球。采用透射电子显微镜(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进行了表征, 探索了碱式硅酸镍钴空心球还原规律, 并研究了双金属催化剂Ni-Co/SiO₂的催化性能。研究发现, 140℃下反应6 h, 产物为核壳结构, 反应12 h时变为空心球结构; 在氢气气氛中800℃下反应5 h, 碱式硅酸镍钴被完全还原为Ni-Co/SiO₂, 还原前后形貌基本不变, 但比表面积有所减小, 孔径增大。Ni-Co/SiO₂空心球用于催化硝基苯加氢反应1 h后, 硝基苯的转化率为67%, 比商用Raney Ni 提高约28%。

Controlled Synthesis and Catalytic Property of Mesoporous Bimetal Ni-Co/SiO2 Hollow Spheres

Using silica as template, mesoporous bimetal Ni-Co silicate hydroxide hollow spheres were synthesized by sacrificial template/interface reaction. There morphologies and structures were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and temperature procedure reduction (TPR). Their reduction rule was explored and catalytic properties of the reduction products on nitrobenzene hydrogenation were investigated. The results show that the structures of bimetal nickel cobalt silicate are core-shell and hollow spheres under 140℃ for 6 h and 12 h, respectively. Bimetal Ni-Co/SiO₂ hollow spheres are obtained after reduction of N silicate hydroxide hollow spheres within 5 h at 800℃ with less specific surface area and bigger pore size than before reduction. But the hollow spheres before and after reduction still share the same morphology. Using bimetal Ni-Co/SiO₂ hollow spheres as catalyst for conversion of nitrobenzene, the conversion rate attains 67% within 1 h, about 28% higher than that of using commercial Raney Ni.