A. A. Azira

Growth Mechanism Of Carbon Nanotubes Prepared By Fluidized Floating Catalyst Method

In this paper, carbon nanotubes were synthesized by fluidized floating catalyst method which yielded high yield even at low temperature; 650° C using camphor oil as carbon source and Argon as carrier gas. Optimum concentration for trimetal alloy catalyst; Fe/Ni/Mg has been found to be the suitable catalyst for producing carbon nanotubes at high yield. Carbon nanotubes are formed by the evaporation of the camphor oil (precursor), which decomposes ‘in situ’ and aggregates on the metal alloy catalyst particles present in the ceramic boat. The morphology of carbon nanotubes were characterized by field emission scanning electron microscopy (FESEM). This result demonstrates that fluidized floating catalyst method is suitable for effective formation of CNTs with average size ∼11.5 nm. The morphological studies support ‘tip growth mechanism’ for the growth of the CNT’s in our case.

Optimization of Fe/Ni/Mg Trimetallic Catalyst for Carbon Nanotubes Growth by Using Fluidized Floating Catalyst Method

Fluidized floating catalyst method has been used for preparing carbon nanotubes with average size ∼11 nm which yielded high yield even at low temperature; 650° C. Optimum concentration of the Fe/Ni/Mg metal alloy catalyst has been found to be at 2.133% for producing carbon nanotubes with high yield. Carbon nanotubes are formed by the evaporation of the camphor oil (precursor), which decomposes ‘in situ’ and aggregates on the metal alloy catalyst particles present in the ceramic boat. From the PXRD analyses, graphite layers detected which provide an indication of the degree of graphitic character. However, by using the Scherrer equation is not suitable for carbon nanotubes as the value is slightly different from the average diameter determine from FESEM micrographs. Since the metallic alloy was obtained by calcining the respective nitrates, it is expected to have residual entrapped nitrogen, which may bond with the depositing CNTs as observed from FTIR spectroscopy.

Vertically Aligned Carbon Nanotubes from Palm Oil Precursor

This paper reports a study on vertically aligned carbon nanotubes (VACNTs) synthesized by thermal chemical vapor deposition (TCVD) method using eco-friendly carbon source; palm oil. Palm oil vaporized at 450oC in argon atmosphere at ambient pressure. For better decomposition of palm oil complex structure, ferrocene were added into palm oil and stirred for 20 minutes prior to synthesis process. The synthesis and annealing duration took 30 and 10 minutes respectively. The field emission scanning electron microscopy (FESEM) and infrared spectroscopy analysis were systematically studied on CNTs produced. The detailed of CNTs properties will be discussed further.

Effect of Catalyst Concentration on the Growth of Palm oil Based Vertically Aligned Carbon Nanotubes

The effects of catalyst concentration on the synthesis of vertically aligned carbon nanotubes (VACNTs) using ferrocene as catalyst and palm oil as bio‐hydrocarbon source in thermal chemical vapor deposition (CVD) method were studied. The CVD reaction took 30 minutes followed by 10 minutes annealing process at various ferrocene concentration; 0.66, 1.33, 2.66, 3.99, 5.33, 6.66 and 7.99 wt% at fixed synthesis temperature 750 °C. The VACNTs were characterized by field emission scanning electron microscopy (FESEM) and Raman spectroscopy. The growth rate, the diameters, and the degree of crystalinity of the VACNTs were found to be dependent on the catalyst concentration.

The Electrical and Optical Properties of PMMA/MWCNTs Nanocomposite Thin Films

The poly(methyl methacrylate) (PMMA)/multi‐walled carbon nanotubes (MWCNTs) nanocomposite thin films have been prepared by spin‐coating technique. The electrical properties as well as UV‐Visible spectrophotometer have been studied as a function of the MWCNTs’ weight percentage. The electrical conductivity of the films increases by several orders of magnitude upon the addition of MWCNTs into PMMA solution. It was observed that the conductivity enhancement is interpreted by the formation of a continuous electron paths or conducting network in the polymer nanocomposite indicated by the efficient dispersion of MWCNTs into PMMA. The optical band gap of the films was assessed using Tauc approximation from the UV‐Vis spectra. The surface morphology was investigated using the scanning electron microscope (SEM) to study on the MWCNTs’ dispersion in the polymer matrix.

Properties Of Carbon Nanotubes Produced Using Fe/Co/Al Trimetallic Catalyst In Fluidized Floating Catalyst Method

Carbon nanotubes (CNTs) were synthesized by fluidized floating catalyst method by using camphor oil as the carbon source and Fe/Co/Al as the catalyst. The catalyst was prepared by sol‐gel method using nitrate salt. Carbon nanotubes were produced by using fluidized floating catalyst method, in low temperature condition; 650° C. The results showed that a thickened submicron vapor grown of multi‐wall nanotubes that produced only with a vaporize catalyst and the hydrocarbon source with diameters of about ∼30 nm. In fact, very few carbon nanotubes have either a particle tip at the end or trapped metal particle inside the wide hollow core of this type of produced carbon material. Structural characterizations have been done by FESEM, FTIR and XRD analyses.

Preparation of Carbon Nanotubes by Seeded Catalyst Method with Palm Oil as Starting Material

Carbon Nanotubes (CNTs) are produced by using Thermal Chemical Vapor Deposition (TCVD). The function of support catalyst is to optimize used of the catalyst. The properties of CNTs produced are determined by Fourier Transmission Infrared Spectroscopy (FTIR). The catalyst was prepared by sol‐gel method where Cobalt, Iron and Nickel were used. Different percentage of support catalyst was added with the catalyst. The palm oil was used as precursor to synthesize the CNTs. The CNTs was then collected and characterized by using FTIR. Increasing the percentage of support catalyst (zeolite) contributes to the unstableness of carbon bonding of CNTs. The CNTs will vibrate more and absorb more energy. From the FTIR peaks, the absorbance energy of CNTs depends on the types of catalyst used.

Efficient Synthesis of Carbon Nanotubes over Zeolites By Thermal Chemical Vapor Deposition

Properties of the influence on the zeolite as the support towards the starting carbon materials by using thermal chemical vapor deposition (Thermal‐CVD) to produced carbon nanotubes (CNTs) are investigated. The CNTs derived from camphor oil (C10H16O), a botanical hydrocarbon, has been found to be a promising precursor of carbon nanotubes (CNTs). Multi‐wall CNTs have been grown from simple pyrolysis of camphor oil in the temperature 650 °C in argon atmosphere at normal pressure using zeolite as a supported on Fe/Ni/Mn catalyst. On the other hand, multi‐wall nanotubes of uniform diameter (∼20–30 nm) could be produced with a yield as high as 90%. Structural characterizations have been done by FESEM, and FTIR analyses. Good crystallinity, high purity, and absence of amorphous carbon and metallic particles are the essential features of camphor oil‐grown nanotubes; which indirectly may be cost effective. The major parameters are also evaluated in order to obtain high‐yield and high‐quality CNTs.

Multi-Walled Carbon Nanotubes by Thermal-CVD Utilizing Palm DHSA as a Precursor

We illustrated the optimization of the growth of multi-wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm-based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over five different trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol-gel method and used to study on the effect of the production of the MWCNTs from palm DHSA. With different catalyst, the characteristics of MWCNTs changes such as diameter and crystallinity which was confirmed by SEM and Raman spectroscopy studies. The trimetallic catalysts give high yield and offer good graphitization of MWCNTs produced from palm DHSA.

The Effect of Temperature on Carbon Nanotubes Grown Using Monometallic Catalyst from Palm Oil Precursor

The effects of temperature on carbon nanotubes (CNTs) by thermal chemical vapor deposition (TCVD) method were systematically studied. Natural hydrocarbon source; palm oil was used as precursor and argon as carrier gas. Palm oil vaporized optimally at 450oC in ambient pressure. The synthesis temperature start at 650°C and were increased at rate of 50°C for series of samples until it reaches maximum temperature of 900°C. The samples were grown on nickel nitrate, which was coated on silicon substrate. The CNTs characteristics were studied using field emission scanning electron microscopy (FESEM), Raman and infrared (IR) spectroscopy. The experimental results revealed that CNTs properties are highly dependent on temperature. It was found that with increasing synthesis temperature, the CNTs diameter decreased initially and then increased after passing an optimum synthesis temperature of 750°C. The bamboo like structure were obviously found at higher synthesis temperature 800°C-850°C while there were few CNTs seen at 900°C.