Preparation of Carbon Nanotubes from CO and in situ Formed Nano-sized Pd Particles

2000 ◽  
Vol 15 (8) ◽  
pp. 1822-1827 ◽  
Author(s):  
M. Andersson ◽  
P. Alberius-Henning ◽  
K. Jansson ◽  
M. Nygren
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Thermogravimetric Analysis ◽  
Selective Dissolution ◽  
X Ray ◽  
Co Concentration ◽  
20 Nm ◽  
Nanotube Growth ◽  
Scanning Electron

Carbon nanotubes, typically of 0.5-μm length and 20-nm diameter, were prepared with good selectivity by disproportionation of CO in He over a Pd/La2O3 catalyst. The catalyst was formed in situ by reduction of a La4PdO7 precursor. The obtained nanotubes had the so-called fishbone structure with the graphitic planes inclined at an angle to the long axis of the nanotube. The effect of CO concentration was studied at 673 °C, and it was found that, among the concentrations studied, 20 vol% CO in the gas was suitable for nanotube growth. The obtained nanotube/La2O3/Pd composite contained typically only 3 wt% nanotubes after 8 h of CO treatment. A process for selective dissolution of La2O3 and Pd was applied, and a product containing 85 wt% nanotubes was obtained. The nanotubes were characterized by high-resolution, transmission, and scanning electron microscope studies, combined with element analyses using energy dispersive spectrometers, x-ray powder diffraction studies, and thermogravimetric analysis.

scholarly journals A Comparative Study of Carbon Nanotubes Synthesized from Co/Zn/Al and Fe/Ni/Al Catalyst

2011 ◽  
Vol 8 (3) ◽  
pp. 1014-1021 ◽  
Author(s):  
Ezekiel Dixon Dikio
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Electron Microscope ◽  
Thermogravimetric Analysis ◽  
Catalyst System ◽  
X Ray ◽  
Transmission Electron ◽  
Catalyst Systems ◽  
Synthesis Of Carbon Nanotubes ◽  
Scanning Electron

The catalyst systems Fe/Ni/Al and Co/Zn/Al were synthesized and used in the synthesis of carbon nanotubes. The carbon nanotubes produced were characterized by Field Emission Scanning Electron Microscope(FE-SEM), Energy Dispersive x-ray Spectroscopy(EDS), Raman spectroscopy, Thermogravimetric Analysis(TGA)and Transmission Electron Microscope(TEM). A comparison of the morphological profile of the carbon nanotubes produced from these catalysts indicates the catalyst system Fe/Ni/Al to have produced higher quality carbon nanotubes than the catalyst system Co/Zn/Al.

Synthesis of Carbon Nanotubes from Palm Oil Precursor by Aerosol-Assisted Catalytic CVD Method

2012 ◽  
Vol 229-231 ◽  
pp. 247-251 ◽  
Author(s):  
M. Maryam ◽  
A.B. Suriani ◽  
M.S. Shamsudin ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Electron Microscope ◽  
Thermogravimetric Analysis ◽  
Palm Oil ◽  
X Ray ◽  
Cvd Method ◽  
Synthesis Of Carbon Nanotubes ◽  
Scanning Electron ◽  
Catalytic Cvd

Carbon nanotubes were produced from the aerosol-assisted catalytic CVD method using palm oil as the precursor and ferrocene as the catalyst. The CNTs were yielded at optimized temperature of 700oC and the Field Emission Scanning Electron Microscope showed the image of CNTs produced. Raman Spectroscopy, energy dispersive X-ray and Thermogravimetric Analysis were then used to further study the Raman Spectra, purity and identification of samples.

Effect of Briquetting Pressure on the Performance of In Situ Formed Sialon in Al2O3-C Refractory Bricks

2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Z Value ◽  
Refractory Bricks ◽  
Scanning Electron

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.

scholarly journals Construction of in situ degradation bacteria of corn straw and analysis of its degradation efficiency

2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Xiujie Gong ◽  
Hongtao Zou ◽  
Chunrong Qian ◽  
Yang Yu ◽  
Yubo Hao ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Degradation Efficiency ◽  
Corn Straw ◽  
X Ray ◽  
In Situ Degradation ◽  
Infrared Spectrometer ◽  
Scanning Electron

Abstract Purpose The highly efficient degradation bacteria were selected from the humus from the very cold straw in China for many years to construct the in situ degradation bacteria, and the degradation efficiency of corn straw was determined by process optimization. Methods According to the main components of corn straw, through morphological, physiological, and biochemical screening, three highly efficient complementary degradation strains were selected to construct the compound flora, and the degradation efficiency was analyzed by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Result The corn straw selected in this paper is mainly composed of cellulose (31.99%), hemicellulose (25.33%), and lignin (14.67%). Through the determination of enzyme activity, strain Streptomyces sp. G1T has high decomposition ability to cellulose and hemicellulose but weak utilization ability to lignin; strain Streptomyces sp. G2T has the strongest decomposition ability to cellulose and hemicellulose among the three strains. The decomposition ability of strain Streptomyces sp. G3T to lignin was the strongest among the three strains. Therefore, by compounding the three strains, the decomposition ability has been greatly improved. The optimal process conditions obtained by single factor and response surface method are as follows: pH is 7, temperature is 30 °C, inoculation amount is 5%, rotational speed is 210 rpm, and the weight loss rate of straw is 60.55% after decomposing for 7 days. A large amount of degradation of corn straw can be seen by Fourier transform infrared spectrometer, field emission scanning electron microscope, and X-ray diffractometer. Conclusion Streptomyces sp. G1T, Streptomyces sp. G2T, and Streptomyces sp. G3T screened from straw humus in very cold areas were used to construct in situ degradation bacteria, which had good straw degradation activity and had the potential to be used for straw treatment in cold areas after harvest. This characteristic makes the complex bacteria become a strong competitive candidate for industrial production, and it is also an effective biotechnology in line with the current recycling of resources.

scholarly journals Karakterisasi Mineral Magnetik Sedimen Sungai Citarum Hilir Melalui Analisa Sifat Magnetik, Mineralogi serta Morfologi Magnetik

POSITRON ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 52
Author(s):  
Kartika Hajar Kirana ◽  
Mechdi Ghazali ◽  
Luh Ayu Eka Safitri Septiana ◽  
Dini Fitriani ◽  
Eleonora Agustine ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Total Dissolve Solid ◽  
X Ray ◽  
Scanning Electron

Sungai Citarum merupakan sungai utama yang ada di Provinsi Jawa Barat yang sangat penting bagi kehidupan sosial dan ekonomi. Di bagian hilir, Sungai Citarum ini banyak melewati daerah pemukiman padat penduduk, daerah industri, dan bahkan pesawahan. Oleh karena itu, perlu kajian mengenai kondisi Sungai Citarum salah satunya dengan mengidentifikasi parameter electrical conductivity (EC), total dissolve solid (TDS), pH dan suhu serta karakteristik mineral magnetik pada sedimen melalui analisis sifat magnetik, mineralogi dan morfologi magnetiknya. Pengukuran parameter EC, TDS, pH dan suhu dilakukan secara in situ pada sampel air Sungai Citarum, pengukuran sifat magnetik dilakukan pada sampel sedimen yang telah dipreprasi, sedangkan pengukuran mineralogi dan morfologi dilakukan pada sampel sedimen yang telah diekstraksi. Sifat magnetik sedimen diketahui dari nilai suseptibilitas magnetik dual frekuensi yang diukur menggunakan Bartington Magnetik Susceptibilitymeter, sedangkan mineralogi dan morfologi magnetik diketahui berdasarkan hasil pengukuran scanning electron microscope–energy disperdsive x-ray (SEM-EDS) dan x-ray diffractometer (XRD). Hasil pengukuran secara in situ pada sampel air menunjukkan bahwa rentang nilai EC, TDS, pH dan suhu berturut-turut adalah (200–4120) mS/cm, (100–2060) ppt, 7,34–9,22, dan (26,8–32,6) oC. Sedangkan, hasil pengukuran sifat magnetik menunjukkan bahwa sampel sedimen Sungai Citarum bagian hilir memiliki nilai suseptibilitas magnetik frekuensi rendah (cLF) dengan rentang (65,00–173,80) x 10-8 m3/kg, sedangkan rentang nilai suseptibilitas magnetik frekuensi tinggi (cHF) adalah (64,90–165,70) x 10-8 m3/kg. Dari kedua pengukuran cLF dan cHF diperoleh rentang nilai cFD (%) sebesar 0,15–4,66. Selanjutnya, hasil analisis morfologi dari citra SEM-EDS dan analisis mineralogi berdasarkan pengukuran XRD menunjukkan dominasi jenis mineral magnetik pada sampel sedimen adalah magnetit. Mineral magnetit ini memiliki morfologi berbentuk oktahedral sebagai representasi mineral magnetik alami dan ada pula yang berbentuk spherule sebagai representasi mineral magnetik karena adanya proses oksidasi akibat kehadiran material antropogenik pada sedimen Sungai Citarum bagian hilir.

scholarly journals X Preparation and Characterization of Carbon-Based Composite Nanofibers for Supercapacitor

2017 ◽  
Vol 17 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Chunxia Wang ◽  
Yuping Chang ◽  
Pibo Ma
Keyword(s):  
Carbon Nanotubes ◽  
Phase Composition ◽  
Electron Microscope ◽  
Surface Area ◽  
Composite Nanofibers ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Abstract Polyacrylonitrile (PAN)/Co(OAc)2/carbon nanotubes (CNTs) composite nanofibers were fabricated via electrospinning with N,N-dimethylformamide (DMF) as solvent, and by carbonization and activation of the above precursor nanofibers, porous carbon composite nanofibers were successfully obtained. Scanning electron microscope, X-ray diffraction, ASAP 2020, and Solartron 1470 were used to characterize the surface morphology, the phase composition, specific surface area, and electrochemical property of the nanofibers, respectively. The result showed that some of the fibers were broken after sintering, and the surface area and pore volume of the porous C/Cu/CNTs were 771 m2/g and 0.347 cm3/g, respectively. The specific capacitance of the composite nanofibers reached up to 210 F/g at the current density of 1.0 A/g. Its energy density and power density were 3.1 Wh/Kg and 2,337 W/Kg, respectively, at the current of 0.5 and 5 mA.

Visualization and in situ contacting of carbon nanotubes in a scanning electron microscope

2005 ◽  
Vol 23 (6) ◽  
pp. 2789 ◽  
Author(s):  
M. D. Croitoru ◽  
G. Bertsche ◽  
D. P. Kern ◽  
C. Burkhardt ◽  
S. Bauerdick ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Scanning Electron

Effect of Sidewall Fluorination on the Mechanical Properties of Catalytically Grown Multi-Wall Carbon Nanotubes

2011 ◽  
Vol 1284 ◽  
Author(s):  
Yogeeswaran Ganesan ◽  
Cheng Peng ◽  
Lijie Ci ◽  
Valery Khabashesku ◽  
Pulickel M. Ajayan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Electron Microscope ◽  
Tensile Testing ◽  
Load Bearing Capacity ◽  
Multi Wall Carbon Nanotubes ◽  
Pristine Mwnts ◽  
Scanning Electron

ABSTRACTWe report on the usage of a simple microfabricateddevice, that works in conjunction with a quantitative nanoindenter inside a scanning electron microscope (SEM), for the in situ quantitative tensile testing of individual sidewall fluorinated multi-wall carbon nanotubes (MWNTs). The stress vs. strain curves and the tensile strength values for five fluorinated specimens have been presented and compared to those of pristine MWNT specimens (data reported earlier). The fluorinated specimens were found to deform and fail in a brittle fashion similar to pristine MWNTs. However, sidewall fluorination was found to have considerably degraded the mechanical properties (tensile strength and load bearing capacity) of the MWNTs.

Effects of Nano-Sized NiF2 Addition in Bi1.4Pb0.6Sr2Ca2Cu3O10+δ Superconductor

2014 ◽  
Vol 895 ◽  
pp. 87-90 ◽  
Author(s):  
Muhammad Hafiz ◽  
Roslan Abd-Shukor
Keyword(s):  
Electron Microscope ◽  
Critical Temperature ◽  
Scanning Electron Microscope ◽  
Electrical Transport ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size ◽  
20 Nm ◽  
Scanning Electron

The effects of NiF2addition on the superconducting and transport properties of Bi1.4Pb0.6Sr2Ca2Cu3O10+δ(Bi-2223) were studied. Bi-2223 superconductor samples were prepared via conventional nitrate coprecipitation method, and 0.01 wt% - 0.05 wt% of NiF2nanoparticles with average size of 20 nm were added into the samples. The critical temperature (Tc) of each sample was measured by using the four-point probe method. Furthermore, phase formation and the microstructure of the samples were identified using x-ray diffraction method (XRD) and scanning electron microscope (SEM) respectively. The optimumTcwas observed for the sample with 0.04 wt% addition of NiF2. Results of electrical transport measurement are presented.

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