Synthesis, Characterization And Properties Of Carbon And Carbonaceous Composite Materials

In this dissertation, carbon materials with sheet-like, honeycomb-like, and bamboo-shaped architectures were prepared via catalytic or reduction pyrolysis routes in stainless-steel autoclave. The growth process of products was investigated, and the properties including adsorption activity and Li+ storage were also studied. Besides, thermal treatment route in inert atmosphere was developed to synthesize Cu@C microspheres with core-shell structure on the basis of solution-based carbonization. In addition, the growth mechanism and the effect of reactant ratio on core-shell structure were also investigated in this paper. The main points are summarized as follows:1. One-dimensional (1D) carbon materials with hierarchical structure were prepared by metallic nickel catalytic pyrolysis of tetrahydrofuran in a stainless-steel autoclave at 600℃. 1D carbon materials were formed by stacking graphite sheets along the [001] direction, and the graphite sheets were 10-40 nm in thickness and 200-300 nm in width. It was confirmed that the catalytic activity of Ni (001) plane was responsible for the formation of 1D carbon material. On the basis of previous study, a possible growth process was proposed. We took RhB as a model pollutant in wastewater to study the adsorption activity of as-prepared 1D carbon materials, and they exhibited a fast (≤5 min) and efficient (> 92%) decolorization activity for dye molecules. It was worth noting that the 1D carbon materials could be reused with high decolorization stability and may find application in water purification. The above results of research have been published in the international journal of CARBON in 2008.2. Hexagonal graphite nanoplatelets (HGNPs) were prepared by copyrolysis of ferrocene and calcium carbide in a stainless-steel autoclave at 600℃. The as-prepared HGNPs were～5 nm in thickness and 500-800 nm in edge length, and the angle of adjacent edges was～120°. It was found that the synergetic reaction of ferrocene and calcium carbide was responsible for the formation of HGNPs, However, low temperature (< 500℃) was not favorable for the synergetic reaction for heterogeneous reaction between gas phase ferrocene and solid pahse calcium carbide. The adsorption activity for rhodamine-B was investigated, and it was concluded that HGNPs exhibited a fast (～5 min) and efficient (～90%) decolorization activity. It should be pointed out that the HGNPs could be reused with high decolorization stability. Besides, HGNPs also exhibited high decolorization activity for general dye molecules such as methyl orange and basic fuchsine, which revealed that HGNPs may find application in water purification.3. Two kinds of porous carbon materials, alveolate carbon spheres and bamboo-shaped carbon nanotubes, were prepared by metallic zinc reduction pyrolysis of glycerol and tetrahydrofuran, respectively. The former had macropores, while the later had both macropores and mesopores. The growth mechanism of bamboo-shaped carbon nanotubes was bottom growth model, and the catalyst was ZnO which came from the reaction of metallic zinc and oxygen in tetrahydrofuran. The insertion-extraction performance of Li+ in two kinds of carbon materials was investigated by using a Teflon battery, and it was found that the Li+ storage property strongly depended on their morphology and structure.4. Carbonaceous matrices containing embedded copper particles were synthesized via a hydrothermal carbonization route by reducing CuCl2 with vitamin C (VC) in the existence of polyacrylamide (PAM) at 180℃, accompanied by the partial carbonization of VC. Cu@carbon (Cu@C) microspheres with core-shell structure were prepared from carbonaceous matrices by further thermal treatment at 600℃. The formation of carbonaceous matrices was found to invole an entrapment-reduction-carbonization process. PAM could entrap Cu2+to form clusters, and VC could convert Cu2+ into metallic Cu and embed them in carbonaceous matrices. Thermal treatment at 600℃in Ar atmosphere induced the diffusion of small Cu nanoparticles and further carbonization of carbonaceous matrices, The core-shell ratio could be conveniently controlled by varying the dose of CuCl2, VC, or PAM. It was found that the carbon shell could effectively shield the metallic Cu core from oxidation in the mixed solution of dilute hydrogen peroxide and nitric acid. The above results of research have been published in the international journal of CARBON in 2009.