scholarly journals Synthesis of Carbon Nanotubes via Liquid Injection Chemical Vapour Deposition as a Vector for the Chemical Recycling of Waste Composite Carbon Sources

Author(s):  
Alvin Orbaek White ◽  
Ali Hedayati ◽  
Tim Yick ◽  
Varun Shenoy Gangoli ◽  
Yubiao Niu ◽  
...  

For every three people on the planet there is approximately two Tonne (Te) of available plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the co-addition to solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas in a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multi-walled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.3% to 14.2%. Since both the CNT diameters and the percentage yield increased with respect to polystyrene addition, we conclude that carbon from the PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid washed Bucky papers produced from each loading, ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, the materials with different loading were mixed to create six wires of an Ethernet cable and tested using iPerf to give uplink and downlink speeds of ~99.5 Mbps, comparable to Cu wire of identical dimension (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for the use case in a Boeing 747-400 over the lifespan of the craft. Due to their lightweight nature the CNT wires decreased the CO2 footprint by 21 kTonne (kTe) over the aircraft lifespan.

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 9
Author(s):  
Alvin Orbaek White ◽  
Ali Hedayati ◽  
Tim Yick ◽  
Varun Shenoy Gangoli ◽  
Yubiao Niu ◽  
...  

For every three people on the planet, there are approximately two Tonnes (Te) of plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the coaddition of solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas at a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multiwalled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.37% to 14.31%. Since both the CNT diameters and the percentage yield increased following the addition of polystyrene, we conclude that carbon from PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid-washed Bucky papers produced from each loading ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, materials with different loadings were mixed to create the six wires of an Ethernet cable and tested using iPerf3; the cable achieved up- and down- link speeds of ~99.5 Mbps, i.e., comparable to Cu wire with the same dimensions (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for a use case in a Boeing 747-400 over the lifespan of the aircraft. Due to their lightweight nature, the CNT wires decreased the CO2 footprint by 21 kTonnes (kTe) over the aircraft’s lifespan.


2021 ◽  
Author(s):  
◽  
Xianming Liu

<p>Carbon nanotubes (CNTs) are a group of pure carbon solid materials that possess one-dimensional structures with diameters down to less than one nanometre. They have interesting physical properties such as very high tensile strength, metallic and semiconducting conductivity, and great potential for applications. This work investigates the synthesis, alignment and purification of multi-walled carbon nanotubes, which were characterized by Electron Microscopy, measurement of electrical properties and Raman scattering. Synthesis of multi-walled carbon nanotubes (MWNTs) was carried out by Chemical Vapour Deposition, using three different precursors: Fe(NO3)3, ferrocene and iron phthalocyanine. Vertically aligned "forests" of large numbers of MWNTs were achieved using ferrocene and iron phthalocyanine as precursors. Products from iron phthalocyanine yield more graphitic CNT nanostructures, as determined by Scanning Electron Microscopy, Transmission Electron Microscopy, Thermogravity Analysis, Raman microscopy and Energy Dispersive X-ray spectroscopy. Patterned growth of vertical MWNTs arrays with a resolution of 2 microns was also obtained, using a predeposited substrate. A High Resolution Transmission Electron Microscope was employed to investigate the inner structures of individual MWNTs, giving well-resolved images of concentric nanostructures with inter-lattice spacings of 0.34 nm. Techniques for purification and manipulation of CNTs are required before CNTs' excellent properties can be exploited. In this thesis, dielectrophoresis (DEP) under high-frequency AC voltages using an array of micron-scale electrodes was adopted as the technique to align MWNTs between these, electrodes. This technique is effective for MWNTs since their long cylindrical structure and the high mobility of their charge carriers allow them to be electrically polarised. As a result, MWNTs experience large DEP forces in an AC electric field. In our experiments, inter-digitated electrodes were used to apply the electric field to CNT suspensions in various solvents. Alignment of CNTs along their axis was achieved within the gaps between adjacent electrodes at a frequency larger than 1.1 MHz, The AC admittance changes between the electrodes were monitored and were observed to be a clear reflection of the accumulation process of MWNTs. Also it was identified that distilled water was a better solvent than ethanol and isopropanol for DEP purpose on MWNTs. In addition, a prototype device was built to selectively purify MWNTs from as-grown samples by combining DEP and re-circulating fluid flow. It was found that this device is able to decrease the impurity content of MWNTs, which is collected on the electrode array, from the suspension of as-grown samples.</p>


REAKTOR ◽  
2013 ◽  
Vol 14 (3) ◽  
pp. 234
Author(s):  
Tutuk Djoko Kusworo ◽  
Desmile Yusufina ◽  
Atyaforsa Atyaforsa

EFFECT OF Co AND Fe ON CARBON NANOTUBES CHARACTERISTICS FROM ACETYLENE USING CATALYTIC CHEMICAL VAPOUR DEPOSITION (CCVD) PROCESS. Carbon Nanotubes (CNTs) is one of the most well known nano-technology applications which the most of attracting the attention of researchers, because it has more advantages than other materials. The application of the CNT has extended into various aspects, such as electronics, materials, biology and chemistry. This research uses a system of Catalytic Chemical Vapour Deposition (CCVD), which aims to determine the influence of Co and Fe as a catalyst and zeolite 4A as a support catalyst with acetylene gas (C2H2) as carbon source in the synthesis of Carbon Nanotubes (CNTs). In this experiment, used the ratio of acetylene gas and flow rate of N2 gas is 1:1 by weight of the catalyst Co/Zeolite and Fe/Zeolite amounted to 0.5 grams at the operating temperature of 700oC for 20 minutes. N2 gas serves to minimize the occurrence of oxidation reaction (explosion) when operating. From analysis result by Scanning Electron Microscopy (SEM) shows the CNTs formed a type of MWNT with different of diameter size and product weight, depending on the size of the active component concentration on the catalyst. The larger of active components produced CNTs with larger diameter, whereas product weight syntheses result smaller. Use of the catalyst Fe/Zeolite produce CNTs with a diameter larger than the catalyst Co/Zeolite.  Carbon Nanotubes (CNTs) merupakan salah satu aplikasi nanoteknologi yang paling terkenal dan banyak menarik perhatian para peneliti, karena memiliki beberapa kelebihan daripada material lainnya. Aplikasi dari CNT telah merambah ke berbagai aspek, seperti bidang elektronika, material, biologi dan kimia. Penelitian ini menggunakan sistem Catalytic Chemical Vapour Deposition (CCVD) yang bertujuan untuk mengetahui pengaruh variasi Cobalt (Co) dan Ferrum (Fe) sebagai katalis dan zeolit tipe 4A sebagai penyangga katalis dengan gas asetilen (C2H2) sebagai sumber karbon dalam sintesis carbon nanotubes (CNTs). Pada penelitian ini digunakan perbandingan laju alir gas asetilen dan gas N2 yaitu 1:1 dengan berat katalis Co/Zeolit  dan Fe/Zeolit masing-masing sebesar 0,5 gram pada suhu operasi 700 oC selama 20 menit. Dari hasil analisa Scanning Electron Microscopy (SEM) menunjukkan CNTs yang dihasilkan pada penelitian ini memiliki tipe Multi Walled Nano Tube (MWNT) dengan ukuran diameter dan berat produk yang berbeda, tergantung dari besarnya konsentrasi komponen aktif pada katalis. Semakin besar konsentrasi komponen aktif akan dihasilkan CNTs dengan diameter yang semakin  besar, sedangkan berat produk semakin kecil. Penggunaan katalis Fe/Zeolit dengan kalsinasi akan menghasilkan CNTs dengan diameter yang lebih besar daripada katalis Co/Zeolit.


2010 ◽  
Vol 442 ◽  
pp. 7-14 ◽  
Author(s):  
M. Mansoor ◽  
Ian Kinloch ◽  
Brian Derby

The production of substrates coated with carbon nanotubes (CNTs) in well-defined patterns is desirable for sensor applications. In the present work, nickel based catalytic inks were prepared and printed on silicon substrates using inkjet delivery. Subsequently, the substrates were subjected to calcination and chemical vapour deposition for the growth of aligned CNTs. Scanning electron microscopy, transmission electron microscopy and Raman spectroscopy were used to characterize the CNTs. Various concentrations and formulations of ink preparations were studied to investigate the effect of these parameters on the growth and structure of the CNTs.


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