Investigation On Morphologies And Properties Of Carbon Nanomaterials Grown Over Ni-Based Hydrotalcite Precursors

As combination of carbon materials and nano-materials, carbon nanotubes and carbon nanofibers have many unique physical and chemical properties. Based on these properties, many potential applications have been proposed for them, including composite reinforced materials, adsorption, hydrogen storage, field emission, catalysts and catalysts carriers, lithium-ion batteries, sensors, new blended and muscle materials, electronic probes and other areas. With the deepening of researchers'detailed work, carbon nanotubes and carbon nanofiber will have more application prospects.Among tens of synthesis methods for these carbon nanomaterials, the thermal chemical vapor deposition (CVD) method attracts more attention and has rapid development in low cost and high efficiency. The catalysts play a crucial role in the CVD process. In addition to the traditional catalysts like Fe, Co, Ni and their alloy, researchers have explored some new catalysts to synthesize carbon nanomaterials with more perfect structures and morphologies or more suitable for practical applications in more areas. It has been found that the basic nature of the exchangeable property of cation in the brucite layer of LDHs and in-situ transformation to composite metal oxides is useful for metal dispersion which is responsible for many potential applications. So the LDHs and the calcined productors LDOs can be used as catalysts and catalysts carriers for metal dispersion becomingly.In this work, we have synthesized NiTi-LDHs and CuNiCrSn-LDHs with different metal ratios. And using the NiTi-LDHs and calcined products of CuNiCrSn-LDHs as catalytic precursors, various morphologies of carbon nanostructures can be produced. The materials have been characterized by XRD, SEM, TG and CV tests. The electrocatalitic activity of the electrodes of Pt particles deposited on the as-grown carbon nanostructures has been attested to be excellent for methanol oxidation.We have synthesized NiAl-LDHs/γ-Al2O3 in y-Al2O3 using in-situ growth method. Carbon nanostructures have been prepared using these LDHs. We have done system exploration and research of effects of different Ni content, precipitation agents for the preparation of LDHs and catalytic time on the structures, morphologies and yield of the carbon nanostructures. And with the introduction of Mg and Cu to NiAl-LDHs/γ-Al2O3, we have investigated the catalyst components'influence on the morphologies of the carbon nanostructures produced by those LDHs. We have attained carbon nanotubes, coiled carbon nanotubes and carbon nanofiber and helical cabon nanofibers and so on. The carbon materials were characterized using XRD, SEM, TEM, Raman and TG-DTA. The supported catalysts have been attested to be reused to catalytic reaction expediently.