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1
Content available Single-walled carbon nanotubes fractionation via electrophoresis
Scheibe B., Lukaszczuk P., Rümmeli M. H., Kalenczuk R. J., Borowiak-Palen E.
Polish Journal of Chemical Technology
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2011
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Vol. 13, nr 3
1-4
EN
This work presents the influence of the sonication time on the efficiency of the metallic/semiconducting (M/S) fractionation of diazonium salt functionalized single-walled carbon nanotubes (SWCNTs) via free solution electrophoresis (FSE) method. The SWCNTs synthesized via laser ablation were purified from amorphous carbon and catalyst particles through high vacuum annealing and subsequent refluxing processes in aqua regia solutions, respectively. The purified material was divided into two batches. The SWCNTs samples were dispersed in 1% SDS solution in ultrasound bath for 2 and 12 hours. Both dispersed SWCNTs samples were functionalized with p-aminobenzoic acid diazonium salt and fractionated via free solution electrophoresis method. Afterwards, the fractionated samples were recovered, purified from surfactant/functionalities by annealing and investigated via UV-Vis-NIR optical absorption spectroscopy (OAS). The efficiency of the fractionation process was estimated through the comparison of the van Hove singularities (vHS) presented in the obtained fractions to the starting SWCNTs.
2
Content available remote A study on the synthesis, characterization and photocatalytic activity of TiO2 derived nanostructures
Zielińska B., Borowiak-Palen E., Kalenczuk R. J.
Materials Science Poland
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2010
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Vol. 28, No. 3
625--637
EN
Syntheses of TiO2 derived nanostructures have been conducted at 210 °C by hydrothermal reaction of commercial TiO2-P25 (Degussa, Germany) in 10 M NaOH aqueous solution. High purity of the asproduced material was confirmed by scanning and transmission electron microscope analyses. The crystallographic structure, as well as the optical and vibronic properties of this material were examined by X-ray diffraction, diffuse reflectance (DR) UV-Vis, resonance Raman spectroscopic methods, respectively. Detailed analysis of the phase composition revealed that the rod-like structures are made up of sodium tetratitanate (Na2Ti4O9). It was also observed that acid treatment of the material (hydrothermal reaction) led to a decrease in the diameters of the nanorods. Finally, the photocatalytic activity of the investigated nanostructures was examined, by observing the reaction photocatalytic decolourisation of two organic dyes (Reactive Red 198 and Reactive Black 5) under UV-light irradiation.
3
Content available Reversible electron charge transfer in single-wall carbon nanotubes
Costa S., Bachmatiuk A., Borowiak-Palen E.
Polish Journal of Chemical Technology
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2008
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Vol. 10, nr 2
1-4
EN
Single-wall carbon nanotubes (SWCNT) have proved to be very special materials due to their unique electronic properties. Over the last years many scientists have dedicated their research to the study of the these materials as an electronic system. Amphoteric doping effects (n-type and p-type), which can be reversed, became a very popular way of manipulating the optic and electronic properties of carbon nanotubes. In the particular case of SWCNT, the most common and widely used procedure, which changes their properties, is acid treatment applied as a purification procedure. The effect of the addition of this kind of the dopant has been widely studied but not fully understood so far. Here, we present a study, of two kinds of SWCNT, produced within different techniques: (i) chemical vapors deposition and (ii) laser ablation. The main difference between the two types is the diameter distribution of the obtained materials, which is broad in the first technique and narrow in the second. After the acid treatment it is possible to observe a diameter sensitive doping effect on both samples. Resonance Raman spectroscopy, optical absorption spectroscopy (OAS) in UV/Vis/NIR and the Fourier transform middle-infrared (FTIR) spectroscopy have been applied for the characterization of the samples.
4
Content available Preparation and characterization of catalyst mix Fe-Co/MgO for carbon nanotubes growth
Steplewska A., Jędrzejewski R., Borowiak-Palen E.
Polish Journal of Chemical Technology
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2008
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Vol. 10, nr 3
1-3
EN
Fe-Co/MgO is one of the most common catalyst mix applied to carbon nanotubes (CNTs) growth in chemical vapor deposition process. Therefore, here we present detailed study on the preparation and characterization of Fe-Co/MgO. The precursors of Fe and Co are iron (II) acetate and cobalt acetates, correspondingly. The molar ratio of the catalyst mix is Fe:Co:MgO=1:1:100. Initially, thermogravimetric analysis (TGA) of the mixture was performed. TGA analysis of it indicated the stepwise mass losses which pointed out the crucial thermal conditions for the changes in the elemental composition, morphology, crystallographic structure and vibrational properties. In current state of the art the lowest growth temperature for singlewalled carbon nanotubes is 550°C in CVD technique and here the characterization of the catalyst mix strongly suggest that this temperature can be decreased what would enhance the compatibility of CNT growth with current complementary metal-oxide-silicon (CMOS) technology for CNTs-based nanoelectronics. The morphology, crystallographic structure, elemental composition of the samples and its spectroscopic properties were performed via high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD) and Infrared spectroscopy (IR), respectively.
5
Content available remote Preparation of ultra-large-scale catalysts for catalytic vapour deposition of carbon nanotubes
Bachmatiuk A., Kaleńczuk R. J., Rümmeli M. H., Gemming T., Borowiak-Palen E.
Materials Science Poland
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2008
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Vol. 26, No. 1
105--111
EN
One of the most important issues in the controlled synthesis of carbon nanotubes is finding a simple way to synthesize the catalyst nanoparticles with a controlled size. The preparation of iron nanoparticles via an organic route has been presented in the paper. The nanoparticles, of the diameter ranging between 9.5 and 31 nm, supported on magnesia, were used as a catalyst in chemical vapour deposition to produce bulk scale carbon nanotubes. Two carbon feedstocks (ethanol and cyclohexane) were examined. In the optimization process, the pyrolysis temperature was varied between 650 st.C and 850 st.C. In this simple approach, no additional carrier gas was used. Multiwalled carbon nanotubes with a very low diameter distribution (19.5-2.5 nm) were fabricated. Their composition was analysed via X-ray diffraction. The samples were characterized by the resonance Raman spectroscopy and high-resolution transmission electron microscopy.
6
Content available remote Iron filled carbon nanotubes for bio-applications
Borowiak-Palen E.
Materials Science Poland
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2008
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Vol. 26, No. 2
413--418
EN
One of the most interesting bio-applications of nanoparticles refers to as "magnetic fluid hyperthermia" (MFH), i.e. a controlled heating of tumor tissue. In the MFH therapy, magnetic nanoparticles are infiltrated in deep tumor tissue and inductively heated by applying alternating current magnetic fields. The biggest challenge of MFH therapy is the temperature control for which fibre-optic thermometers should be inserted into a tumor. A potential way to overcome this problem seems to be application of carbon nanotubes filled with iron which could provide in-situ temperature controlling. Therefore, the synthesis routes of iron filled single-walled carbon nanotubes (Fe-SWCNT) and iron filled multi-walled carbon nanotubes (Fe-MWCNT) has been presented. These two types of nanostructures were prepared via wet chemistry technique and by in situ single step chemical vapour deposition for Fe-SWCNT and Fe-MWCNT, respectively. The samples were examined by means of transmission electron microscopy, in bright and dark field images modes, and X-ray diffraction.
7
Content available remote Characterization of carbon nanotubes by Raman spectroscopy
Costa S., Borowiak-Palen E., Kruszyńska M., Bachmatiuk A., Kaleńczuk R. J.
Materials Science Poland
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2008
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Vol. 26, No. 2
433--441
EN
Application of Raman spectroscopy to analyse carbon nanotubes has been presented. Having a mixture of various carbon nanotube samples, one can easily distinguish, in a quick experiment, presence of singlewalled, doublewalled and multiwalled carbon nanotubes (SWCNT, DWCNT, MWCNT, respectively). The so-called G-line is a characteristic feature of the graphitic layers and corresponds to the tangential vibration of carbon atoms. Another characteristic mode is a typical sign of defective graphitic structures (D-line). A comparison of the intensity ratios of these two peaks gives a measure of the quality of the bulk samples. In addition, there is a third mode, named the radial breathing mode (RBM) which is very sensitive to the diameter of SWCNT and DWCNT. Additional option is application of Raman microscopy for mapping analysis and depth profiling to view the changes of intensity in various directions in the sample.
8
Content available remote Badania nad syntezą i spektroskopową charakterystyką wielościennych nanorurek węglowych domieszkowanych azotem
Bachmatiuk A., Ruemmeli M. H., Borowiak-Palen E.
Przemysł Chemiczny
|
2007
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T. 86, nr 9
898-900
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