二氧化硅辅助制备CuCo_2O_4纳米尖晶石及其催化性能

Preparation of Nano-spinel CuCo_2O_4 with Silica and Its Catalytic Properties

采用无定型氧化硅辅助制备了CuCo_2O_4纳米尖晶石氧化物,研究了其在对硝基苯酚催化还原中的催化活性。采用X射线衍射仪、扫描电子显微镜等对Cu Co_2O_4纳米尖晶石的形成机制、晶相结构、微观相貌等进行研究。结果表明:基于有机硅前驱体获得的无定型氧化硅可以与Cu Co_2O_4尖晶石氧化物有效复合,有利于抑制Cu Co_2O_4粒子尺寸的长大,并且不会与Cu Co_2O_4发生相间反应。进而通过Na OH热碱溶液处理可以高效刻蚀Cu Co_2O_4–无定型氧化硅复合氧化物中二氧化硅,从而生成纳米尺度Cu Co_2O_4尖晶石粒子,其微观形貌与粒子尺寸与传统方法制备的Cu Co_2O_4明显不同,具有更高的孔隙率和更小的晶粒尺寸。相对于传统方法制备的Cu Co_2O_4尖晶石材料,以无定型氧化硅辅助制备的Cu Co_2O_4纳米尖晶石具有更高的催化活性与稳定性。

Nano-sized CuCo2O4 spinel oxides were prepared by using amorphous silica.Their activities in catalytic reduction of p-nitrophenol were investigated.The formation mechanism,crystal structure and surface morphologies of nano-sized CuCo2O4spinels were analyzed by X–ray diffraction and scanning electronic microscopy.The results indicate that amorphous silica can be effectively combined with CuCo2O4 spinels,inhibiting the growth of CuCo2O4 crystals,whereas no inter-phase reaction between Cu Co2O4 and amorphous silica occurs.Meanwhile,the amorphous silica can be efficiently leached from CuCo2O4-amorphous silica composite oxides and thus CuCo2O4 spinel nanoparticles can be obtained.The surface morphology and particle size of Cu Co2O4nanoparticles with a higher porosity and a smaller particle size are distinctly different from those of Cu Co2O4 prepared by the conventional method.In p-nitrophenol catalytic reduction,CuCo2O4 nanoparticles obtained by silica doping method exhibit higher catalytic activity and stability,compared to CuCo2O4 synthesized by the conventional method.