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机构地区:[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001
出 处:《新型炭材料》2004年第1期1-6,共6页New Carbon Materials
基 金:国家自然科学基金(59872047) ~~
摘 要: 通过热引发方式使炸药-催化剂前驱体-碳氢化合物体系在密闭反应管中发生爆炸合成碳纳米管。采用TEM,HRTEM,XRD和TG等方法研究了以二茂铁、甲酸镍和乙酸钴作为催化剂前驱体对所合成碳纳米管产物的形貌、微观结构和纯度的影响。以乙酸钴为前驱体可以得到纯度较高(约80%~90%)、微观结构较好的管腔中空的碳纳米管。以二茂铁为前驱体,只有约10%~20%的碳管生成且多呈竹节状形貌。以甲酸镍为前驱体,得到的碳管纯度也不高(约10%~20%),碳管管壁富含结构缺陷,相当多的碳管端口膨胀成直径约为160nm的纳米泡。XRD分析表明这些催化剂前驱体在爆炸反应后均被分解、还原为金属单质。通过对生成的碳纳米管的质量和纯度进行比较,得出本方法中催化剂的催化活性依次为:钴>铁>镍,并对本方法中高碳源浓度环境下不同催化剂的活性差异作了简要分析。Carbon nanotubes were prepared by the heat-induced detonation of an explosive-catalyst precursor-hydrocarbon system in a sealed stainless steel pressure vessel. TEM, HRTEM, XRD and TG techniques were employed to investigate the effect of the catalyst precursors of ferrocene, nickel formate and cobalt acetate on the growth of the nanotubes. The morphologies, structure and crystallinity of carbon nanotubes are largely dependent on the kind of catalyst. Cobalt acetate acting as catalyst precursor can yield high-purity (about 80 %-90 %) carbon nanotubes with good microstructures and hollow channels. Ferrocene can give low-purity ( 10 %-20 %) nanotubes with most of them having a bamboo-like appearance. Nickel formate precursor generates 10 %-20 % nanotubes with substantial structural defects. Many ends of the Ni-catalyzed nanotubes are blown into a bulb with diameters up to similar to160 nm. XRD characterization indicates that these metal compounds are subjected to decomposition and a reduction reaction after the detonation and are converted into metallic nanoparticles, which show important catalytic activity for the nucleation and growth of carbon nanotubes under the experimental conditions. Based on the differences in the quality and purity of the nanotubes, the activity of the catalysts follows the order: Co > Fe > Ni. The diverse activities exhibited by different catalysts in the specific high carbon concentration environment generated by detonation are discussed briefly.
关 键 词:催化剂 碳纳米管 爆炸法 碳氢化合物体系 二茂铁 甲酸镍 乙酸钴 催化活性
分 类 号:TB383[一般工业技术—材料科学与工程]
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