A.B. Suriani

Variety of Bio-Hydrocarbon Precursors for the Synthesis of Carbon Nanotubes

In this work, we have synthesized carbon nanotubes (CNT) using different bio-hydrocarbon precursors namely palm, olive, coconut, corn and sesame oils. Prior to the synthesis process, thermogravimetric analysis (TGA) characterization was performed on the carbon precursors to facilitate the optimization procedures of CNT and reach maximum yield and higher quality CNT. The CNT arrays were deposited on a silicon substrate by thermal catalytic decomposition of the precursor using 5.33 wt% ferrocene. The synthesis was carried out at 750 °C for 60 min under argon ambient. The samples were characterized using field emission scanning electron microscopy, micro-Raman spectroscopy and TGA analysis. The difference in oil density resulted in different quality and tube diameter of CNT produced. Among all, the CNT synthesized from coconut oil can be considered as the best bio-hydrocarbon precursor for higher quality (ID/IG ~0.62) and good purity (81.95 %) CNT.

Effect of Temperature on the Growth of Vertically Aligned Carbon Nanotubes from Palm Oil

The effects of synthesis temperature on the quality and quantity of vertically aligned carbon nanotubes (VACNT) were studied using high resolution scanning electron microscopy, and micro-Raman spectroscopy. The VACNT was synthesized by Fe catalytic decomposition of palm oil deposited on silicon substrate by thermal chemical vapour deposition method. The analysis shows that the growth rate increases from 3.8 to 5.5 µm/min as the temperature was increased from 750 to 800°C. The nanotube diameters were observed bigger at low temperature range. Smaller and uniform diameter (~15 nm) was found at 750°C and the increment in diameter size was seen at higher temperature range. Smaller graphite Raman “G” peak width, low ID/IG ratio (~0.52) indicated higher crystallinity of the nanotube and moderate I2D1/ I2D2 ratio for second order Raman peak was also detected at synthesis temperature of 750°C. These results indicated that the optimum synthesis temperature for higher quality VACNT production was at 750°C.

Temperature effects on the production of carbon nanotubes from palm oil by thermal chemical vapor deposition method

In this study we report the effect of various synthesis temperatures of 600 - 1000°C for the synthesis of carbon nanotubes (CNT). Bio-hydrocarbon precursor namely palm oil was utilized as a starting material by thermal vapor deposition method. Ferrocene at 5.33 wt% was directly mixed with palm oil precursor for 30 mins synthesis time. The prepared CNT was collected from the furnace wall and then characterized by field emission scanning electron microscopy, scanning transmission electron microscopy, fourier transform infrared spectroscopy and thermogravimetric analysis. The density, diameter and the purities of the CNT were found to be highly dependent on the temperature changes. The synthesis temperature of 800°C was considered to be the optimum temperature for higher quality and quantity of CNT production.

Raman investigation of rutile-phased TiO2 nanorods/nanoflowers with various reaction times using one step hydrothermal method

Rutile-phased titanium dioxide nanorods (r-TNRs) and rutile-phased titanium dioxide nanoflowers (r-TNFs) were deposited on fluorine-doped tin oxide coated glass by using one step hydrothermal method at a fixed temperature of 150xa0°C. The hydrothermal treatment was conducted by varying the reaction time at 2, 3, 4, 5, 6, 7 and 8xa0h. The effect of reaction time on surface morphology, structure property, crystallite size and Raman spectra was investigated. The nanostructure samples were analysed using X-ray diffractometer, field emission-scanning electron microscope, micro-Raman spectroscopy, and energy-dispersive X-ray spectroscopy. The resulting micro-Raman spectra show abnormal behaviour of Raman intensity. The micro-Raman spectra of the nanostructure samples exhibit insignificant changes and shifting of Raman bands with increasing reaction time. This behaviour can be attributed to the shape and surface morphology distribution of r-TNRs/r-TNFs.

Impact of Thermal Annealing under Nitrogen Ambient on Structural, Micro-Raman, and Thermogravimetric Analyses of Camphoric-CNT

A systematical study of the effects on thermal annealing treatment under nitrogen ambient on the structural, micro-Raman, and thermogravimetric analyses of camphoric-carbon nanotubes (CNT) has been undertaken. Heat treatment of camphoric-CNT under nitrogen ambient was found to be an efficient technique of removing noncrystalline carbon and residual transition metal. Based on structural analysis, the heat-treated samples showed a clear view of overall camphoric-CNT structure.

Preparation of Palm Oil Based Carbon Nanotubes at Various Ferrocene Concentration

In this work, different ferrocene concentration (1.0-8.0 wt%) of bio-hydrocarbon palm oil precursor were utilized to investigate its effect on the characteristics of the produced carbon nanotubes (CNT). The palm oil-ferrocene mixture was vaporized at 450°C and pyrolyzed at 800°C for 30 min time in argon ambient. The CNT were analyzed using field emission scanning electron microscopy, scanning transmission electron microscopy, fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The analysis confirmed different diameter and morphologies of CNT were formed when different ferrocene concentration were used. FTIR spectra show the prominent peak at ~1445, 1736, 2851 and 2925 cm-1 that are identified as CNT and C–Hx respectively.

Effect of iron and cobalt catalysts on the growth of carbon nanotubes from palm oil precursor

Catalysts which are typically a transition metal is mandatory and plays an important role in the production of CNT. In this work, the effect of iron (Fe) and cobalt (Co) nitrate catalyst on the growth of carbon nanotubes (CNT) were systematically studied. Green bio-hydrocarbon precursor namely palm oil was used as a precursor. The synthesis was done using thermal chemical vapour deposition method at temperature of 750°C for 15 min synthesis time. The Fe and Co solution were spin-coated separately on silicon substrate at speed of 3000 rev.min-1. The CNT characteristics were analyzed using field emission scanning electron microscopy and micro-Raman spectroscopy. The experimental results revealed that CNT properties were strongly affected by the catalyst type. CNT catalyzed by Co yields large diameter, crooked tube and lower quality, whereas CNT produced by Fe catalyst results in the smallest diameter and reasonably good graphitization. As a conclusion, Fe was considered as the optimum catalyst for better CNT structure and crystallinity. This was due to efficient, uniform and stable Fe catalytic activity as compared to Co catalyst in producing CNT.

The Effect of Synthesis Temperature on the Growth of Carbon Nanotubes from Waste Chicken Fat Precursor

The effects of synthesis temperatures on the growth of carbon nanotubes (CNT) from waste chicken fat as carbon source were systematically studied. The synthesis was carried out in dual heating zone tube furnace at synthesis temperature between the ranges of 600-900 °C. The waste chicken fat vaporization temperature was fixed at 470°C. The samples were characterized using field emission scanning electron microscopy, micro-Raman spectroscopy and thermogravimetric analyzer. In this experiment, vertically aligned CNT (VACNT) were identified at synthesis temperature ranged of 750-800°C. Among all, the synthesis temperature of 800 °C produced highest yield of VACNT with growth rate of 282 nmmin-1, small nanotubes diameter of 19.8-31.7 nm, 91% pure and high crystallinity (ID/IG ratio of 0.39). At low synthesis temperatures of 600-650°C, no CNT was produced. At high synthesis temperatures of 850-900°C, bigger nanotubes diameter and higher ID/IG ratio were observed which indicates lower nanotubes quality were produced at this temperature range.

Scaled-up prototype of carbon nanotube production system utilizing waste cooking palm oil precursor and its nanocomposite application as supercapacitor electrodes

A simple approach has been introduced for the first time for a scaled-up prototype of a carbon nanotube (CNT) production system by utilizing waste cooking palm oil (WCPO) as carbon feedstock. A modified thermal chemical vapor deposition (TCVD) setup is equipped with a peristaltic sprayer to continuously supply the precursor and catalyst into the system. A total amount of 1000xa0ml WCPO precursor was sprayed continuously during the experiment with 5.33xa0wt% ferrocene as catalyst at a flow rate of 30xa0ml/min. A total of ~433xa0g CNT were produced with a high carbon conversion rate of 56xa0%. The produced CNT were then characterized by using electron microscopy, micro-Raman spectroscopy, and thermogravimetric analysis. Growth of dense CNT with a high purity of ~87xa0% and good crystallinity (ID/IG ratio ~0.47) occurred. A CNT/natural rubber-latex (NRL) nanocomposite was also prepared by using latex nanotechnology for supercapacitor application. The nanocomposite exhibited a good capacitance performance with a specific capacitance of 81.82xa0F/g. This study determined that a high production of CNT using modified TCVD method provided benefits for its utilization as composite material, especially CNT/NRL nanocomposite, for supercapacitor application.

Carbon Nanotubes: A Brief Outlook on History, Synthesis Methods and Various Bio-Hydrocarbon Sources

This paper reports a brief outlook of carbon nanotubes (CNT) history, synthesis methods as well as natural carbon sources such as camphor powder, turpentine, eucalyptus, palm, neem, coconut, castor, olive, corn, sesame oil, palm olein, waste cooking palm oil and waste chicken fat.