铁基多元催化剂组分对V型火焰法生长碳纳米管的影响

为了实现火焰法批量制备碳纳米管,采用自行研发的V型火焰燃烧器,深入研究催化剂组分对碳纳米管的影响,并开发新型催化剂。利用扫描电镜、能谱仪和拉曼光谱仪分析不同催化剂所得产物的形态、质量和结晶度;通过分析程序升温还原曲线和X射线光电子能谱,研究不同催化剂活性组分及助催化组分对催化剂性质的影响。结果表明:通过选择活性组分和配合组分,能够控制碳纳米管的形态和质量,开发了能够生长高密度簇状碳纳米管的三元催化剂;本实验条件下,铁作为活性组分要优于镍,少量的镍以游离态NiO存在,激活催化剂催化活性;铬不适合作为活性组分,在催化剂中起到分散剂的作用,使活性组分分散,促进簇状碳纳米管的形成;Fe~(2+)/Fe~(3+)的比例影响催化剂催化活性,Fe~(2+)/Fe~(3+)比例减小能够提高催化剂的还原性及催化活性。可见,通过深入研究不同组分的作用,进而研制新型催化剂,能够改善V型火焰法生长碳纳米管的形态及产量,为批量生产特定形态的碳纳米管提供低成本、简单易操作的有效方法。

Effects of Ingredients in Iron-Based Multicomponent Catalyst on the Synthesis of Carbon Nanotube by V-type Flame

In order to realize batch preparation of carbon nanotubes by flame method, a self-developed V-type flame burner was used to study the effects of components in catalyst on carbon nanotubes growth to develop new catalyst. The morphology, quality and crystallinity of the products were analyzed by scanning electron microscope, energy dispersive spectrometer and Raman spectrometer; the effects of active components and promoters on the properties of the catalysts were studied by analyzing the temperature programmed reduction curve and X-ray photoelectron spectroscopy. The results show that: the morphology and quality of carbon nanotubes can be controlled by selecting the active component and coordination component, and a ternary catalyst for the growth of high-density cluster carbon nanotubes has been developed. Under the experimental conditions, iron is better than nickel as the active component, and a small amount of nickel exists as free NiO, which promotes the catalytic activity of the catalyst; chromium is not suitable as the active component but plays an important role as dispersant to make the active components disperse which finally promotes the formation of cluster carbon nanotubes. The ratio of Fe²⁺/Fe³⁺ affects the catalytic activity of the catalyst, the reduction and catalytic activity of the catalyst can be improved by reducing the ratio of Fe²⁺/Fe³⁺. It can be seen that the morphology and yield of carbon nanotubes grown by V-type flame method can be improved by developing new catalysts through in-depth study of the effects of different components. Eventually push forward the effective method with low cost, simple and easy operation for the mass production of specific morphology of carbon nanotubes.