The effect of processing conditions on carbon nanostructures formed on an iron-based catalyst
The effect of processing conditions on carbon nanostructures formed on an iron-based catalyst
复制标题
DOI：
10.1016/j.carbon.2006.02.030
复制
发表时间：
2006-09
期刊：
影响因子：
10.9
通讯作者：
S. McCaldin;M. Bououdina;D. Grant;G. Walker
中科院分区：
文献类型：
--
作者：
S. McCaldin;M. Bououdina;D. Grant;G. Walker
研究了乙烯和氢气在氧化铁催化剂前体上化学气相沉积（CVD）过程中形成的碳纳米结构。在合成过程中观察到石墨纳米纤维和碳纳米管，观察到的结构取决于所使用的温度和气体混合物（C2 H4和H2）。在不同温度下研究了100%至5%乙烯在氢气中的混合物。在合成过程中，氧化铁（III）转化为碳化铁（Fe 3C）。使用透射电子显微镜和X-射线衍射的样品进行了表征。在气流中具有高氢含量（约80%）的情况下观察到丝状纳米结构，而在约20%H2的情况下没有观察到丝状结构。合成温度在500 ° C和800°C之间变化，较高的温度产生较高的碳沉积速率，但也影响观察到的纳米结构。然而，发现在CVD期间增加温度并不改变沉积的碳的类型，但确实增加了沉积速率，从而提供了增加所需类型的碳纳米结构的生长产率的途径。
The carbon nanostructures formed during chemical vapour deposition (CVD) of ethene and hydrogen over an iron(III) oxide catalyst precursor have been investigated. Graphitic nanofibres and carbon nanotubes were both observed during synthesis, with the structures observed depending on the temperature and gas mix (C2H4and H2) used. Mixtures ranging from 100% to 5% ethene in hydrogen were investigated at different temperatures. During the synthesis, the iron(III) oxide was transformed into iron carbide (Fe3C). The samples were characterised using transmission electron microscopy and X-ray diffraction. Filamentous nanostructures were observed with high hydrogen content (⩾80%) in the gas stream, whereas no filamentous structures were observed with ⩽20% H2. The temperature of synthesis was varied between 500 and 800°C, with higher temperatures giving higher carbon deposition rates, but also affected the nanostructures observed. However, it was found that increasing the temperature during CVD did not change the type of carbon deposited but did increase the deposition rate, providing a route to increase growth yields for a desired type of carbon nanostructure.