Decorating Metal Nanoparticles On Carbon Nanotubes And Its Application

Carbon nanotubes have attracted much interest in the fields of catalysts and composites since their discovery owing to their high specific surface area and electronic properties. At present, the synthesis of muiti-walled carbon nanotubes (MWCNTs) is well established;some even can be used for large-scale production. However, many problems still exist in view of its pretreatments and applications.In this paper, different MWCNTs were decorated by different metal nanoparticles (Ni, Fe). First, one kind of bunched MWCNTs which can be synthesized for large-scale were decorated by Ni nanoparticles. The results show high-density and homogeneous dispersion of nickel nanoparticles, with a particle size distribution of 20⁵0nm. By XRD and HRTEM, most of these particles supported on the surface of carbon nanotubes were mainly nickel, only a few NiP₂ and NiO. Then Ni/CNTs's catalytic property in liquid benzene hydrogenation was studied through the reaction in reactor. The time of the electroless plating of the Ni/CNTs used in reaction was 5, 10, 15min, respectively. The results show that the as-prepared products possess good catalytic property, which was affected by the distribution and the size of the particles, which can be controlled by plating time. The study will be good for the further research in an active catalyst.A facile method was also developed to decorate the carbon nanotubes (pretreatment by HNO₃) by Ni nanoparticles. When the products underwent drying, annealing in N₂, annealing in N₂/C₂H₂, the phases changed as follows: Ni(NO₃)₂→NiO (anneling in N₂ for 5min) →Ni (anneling in N₂ for 5min 10-20min) →graphite encapsutlated crystal Ni nanoparticles. It's an interesting phenomenon that chemical morphology changes with different final treatment. When the same method was applied on decorating CNTs by Fe nanoparticles, different chemical morphology of Fe was produced according to the different final treatment, i.e., Fe(NO₃)₃→Fe₂O₃→Fe₃O₄→Fe₃O . The results show that the nanoparticles deposited on carbon nanotubes have a high purity by XRD and a well crystallinity by HRTEM. The products can be controlled by different final treatment. Therefore, it's facile and can be used in catalysis industry.