Enhanced Carbon Nanotubes Growth Using Nickel/Ferrocene-Hybridized Catalyst

Abstract

Tall, crystalline carbon nanotubes (CNTs) are desired to successfully integrate them in various applications. As the crystallinity of CNTs improves with increasing growth temperatures, higher growth temperatures are required to obtain crystalline CNTs. However, in a typical chemical vapor deposition (CVD) process, CNT growth rate reduces when the growth temperature exceeds a specific level due to the degradation of the catalyst particles. In this study, we have demonstrated the improved catalytic activity of nickel/ferrocene-hybridized catalyst as compared to sole ferrocene catalyst. To demonstrate this, CNTs are grown on bare silicon (Si) as well as nickel (Ni) catalyst-deposited substrates using volatile catalyst source (ferrocene/xylene) CVD at the growth temperatures ranging from 790 to 880 °C. It was found that CNTs grown on bare Si substrate experience a reduction in height at growth temperature above 860 °C, whereas the CNTs grown on 10 nm Ni catalyst-deposited substrates experience continuous increase in height as the temperature increases from 790 to 880 °C. The enhancement in the height of CNTs by the addition of Ni catalyst is also demonstrated on 5, 20, and 30 nm Ni layers. The examination of CNTs using electron microscopy and Raman spectra shows that the additional Ni catalyst source improves the CNT growth rates and crystallinity, yielding taller CNTs with a high degree of structural crystallinity.

The Effect of Nickel Coating on Stainless steel 316 on Growth of Carbon Nanotube from Polypropylene Waste

“…Also, impurities that are dominated by amorphous carbon are also seen in all variations that are characterized by light aggregates. As shown in the XRD results, other impurities seen in SEM in the form of iron oxide in the structure of Fe2O3 derived from SS 316 fall out which are marked by flakes and also excessive Fe content in carbon sources [24] Fe particles will dominate CNT growth. In sample SS5, there was also a formation of a long tubular nanotube, but Fe particles were also encapsulated in the CNT which caused lumps of impurities detected in XRD.…”

Synthesis of SiC/SiO2 core–shell nanowires with good optical properties on Ni/SiO2/Si substrate via ferrocene pyrolysis at low temperature

“…The Ni catalyst is very important in the process of preparing SiC nanowires at low temperature using the CVD method. Because it can decrease the decomposition temperature of the hydrocarbon gas [29][30][31][32] and according to the Lim et al study 44 , the production of CNTs with Ferrocene precursor shows low quality, but the growth with nickel added shows good quality. Thus, the nickel catalyst added can also promote the growth quality of SiC nanowires.…”

“…Although the Ferrocene has iron atom, decomposition efficiency of hydrocarbon gas is poor for growing CNT according to YD Lim et al study 44 . For the hydrocarbon gas decomposition process, the catalyst activities are Ni > Co > Fe, the nickel has the best growth quality (growth rates and yield) 30 , 32 , 46 .…”

“…Besides, in order to grow SiC nanowires at lower temperature, many precursors have been tried, such as methyltrichlorosilane (MTS) 33,34 , polycarbosilane (PCS) 35 , polymethylsilane (PMS) 36 , ferrocene [37][38][39][40][41] or mixed precursors 42,43 , etc. Among these, ferrocene is a cheaper and safer precursor and it has been demonstrated to be an efficient catalyst precursor for the synthesis of carbon nanotubes 44 , whereas it is seldom to be used for the synthesis of SiC/SiO 2 nanowires. Niu and Wang synthesized 3C-SiC nanowires via CVD by evaporating ferrocene onto a Si wafer at 1550 °C 37 .…”

Engineered Carbon Nanotubes: Review on the Role of Surface Chemistry, Mechanistic Features, and Toxicology in the Adsorptive Removal of Aquatic Pollutants.

“…The carbon solubilizes in the metal catalysts until its saturation limit and then crystalizes out as CNT . It was observed that application of higher temperatures results in crystalline CNT, but this also leads to the decomposition of the metal catalysts thus reducing the growth rate . Various researchers reported the growth of CNT via CVD technique by two established mechanisms namely vapor‐liquid‐solid (V LS ) and vapor‐solid‐solid (V SS ).…”