Application of nitrogen-doped multi-walled carbon nanotubes decorated with gold nanoparticles in biosensing. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 27 (2023), 10, S. 2645-2658
Novel films consisting of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were fabricated by means of chemical vapor deposition technique and decorated with gold nanoparticles (AuNPs) possessing diameter of 14.0 nm. Electron optical microscopy analysis reveals that decoration of N-MWCNTs with AuNPs does not have any influence on their bamboo-shaped configuration. The electrochemical response of fabricated composite films, further denoted as N-MWCNTs/AuNPs, towards oxidation of dopamine (DA) to dopamine-o-quinone (DAQ) in the presence of ascorbic acid (AA) and uric acid (UA) was probed in real pig serum by means of cyclic voltammetry (CV) and square wave voltammetry (SWV). The findings demonstrate that N-MWCNTs/AuNPs exhibit slightly greater electrochemical response and sensitivity towards DA/DAQ compared to unmodified N-MWCNTs. It is, consequently, obvious that AuNPs improve significantly the electrochemical response and detection ability of N-MWCNTs. The electrochemical response of N-MWCNTs/AuNPs towards DA/DAQ seems to be significantly greater compared to that of conventional electrodes, such as platinum and glassy carbon. The findings reveal that N-MWCNTs/AuNPs could serve as powerful analytical sensor enabling analysis of DA in real serum samples.
https://doi.org/10.1007/s10008-023-05562-2
Synthesis and electrochemical properties of sulfur-nitrogen-doped multi-walled carbon nanotubes. - In: Fullerenes, nanotubes & carbon nanostructures, ISSN 1536-4046, Bd. 31 (2023), 11, S. 1082-1095
Multi-walled carbon nanotubes doped with sulfur and nitrogen (S-N-MWCNTs) were grown onto silicon/silicon oxide wafer by means of chemical vapor deposition upon decomposition of dimethyl sulfoxide (DMSO) and acetonitrile (ACN) in presence of catalyst. The S-N-MWCNTs were characterized by scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The findings demonstrate that S-N-MWCNTs exhibit bamboo-shaped nanostructure, quite similar to pure nitrogen-doped carbon nanotubes. The S-N-MWCNTs were investigated with respect to their electrochemical response to ferrocyanide/ferricyanide, [Fe(CN)6]4-/3- in potassium chloride aqueous solutions by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The recorded CVs demonstrate strong dependence of electrochemical response, electron transfer kinetics, and sensitivity of S-N-MWCNTs on concentration of decomposed DMSO precursor. Namely, upon increasing concentration of decayed DMSO up to 2% wt. the current density, the electron transfer kinetics, and the sensitivity of S-N-MWCNTs toward [Fe(CN)6]4-/3- tend to enhance. The extracted EIS results approve that when DMSO reaches the optimum concentration of 2% wt. the barrier for electron transfer decreases significantly leading, consequently, to faster electron transfer kinetics. The S-N-MWCNTs exhibit considerable stability and excellent reproducibility, and thus it can be considered suitable analytical tool for detection of redox systems at micromolar level.
https://doi.org/10.1080/1536383X.2023.2240916
Synthesis, characterization, and electrochemical performance of reduced graphene oxide decorated with Ag, ZnO, and AgZnO nanoparticles. - In: Carbon, ISSN 1873-3891, Bd. 213 (2023), 118178
Graphene oxide (GO) derived from the oxidization of graphite exhibits high specific surface area with potential in electrochemical applications. Furthermore, silver and zinc oxide nanoparticles, further denoted as AgNPs and ZnONPs, respectively, display superior physicochemical and electronic properties, that would significantly improve the electrocatalytic properties by being applied in electrochemical sensing. Consequently, in the present work, three different hybrid nanomaterials consisting of reduced graphene oxide (rGO) modified with either AgNPs, ZnONPs, or combined AgZnONPs were synthesized and characterized. The synthesis of GO was performed by a modified Hummer's method, while the decoration of GO with the nanoparticles was carried out by self-assembly solvothermal processes. The Ag-rGO, ZnO-rGO, and AgZnO-rGO nanocomposite hybrid materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDX). Furthermore, the electrochemical responses of the fabricated nanocomposites towards the standard ferrocyanide/ferricyanide [Fe(CN)6]3-/4- redox system were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The results have been explained in terms of structural differences between the nanoparticles formed on the surface of the fabricated nanocomposite materials. Namely, the improved electrochemical performance of ZnO-rGO can be attributed to the high surface to volume ratio of ZnO, which provides greater area of electrode/electrolyte junction and consequently, large number of sites at the electrolyte-ZnO interface. The aim of the present work is the fabrication of novel high-performance rGO-based nanomaterials for applications in electrochemical sensing.
https://doi.org/10.1016/j.carbon.2023.118178
Application of carbon-based quantum dots in photodynamic therapy. - In: Carbon, ISSN 1873-3891, Bd. 203 (2023), S. 273-310
Photodynamic Therapy (PDT) is a non-invasive therapeutic modality that can treat a wide variety of cancer types by means of photosensitizer drug, light, and oxygen. Due to enhanced specificity and fewer side effects, PDT can be an alternative approach for cancer treatments. However, conventional photosensitizers (PSs) exhibit low selectivity, hydrophobicity, and limited photophysical properties. Nanotechnology emerges as a potential solution to these issues and improves PDT efficiency. Nanomaterials such as Carbon Quantum Dots (CQDs) and Graphene Quantum Dots (GrQDs) have been widely applied on PDT research recently, regarding their excellent photoluminescence properties, biocompatibility, as well as their hydrophilicity. The present review article summarizes the main features of PDT and carbon-based quantum dots with an emphasis on used PSs and methods for synthesis of carbon dots. Additionally, the most recent applications of CQDs and GrQDs in PDT have been extensively discussed. The main conclusion that arises is that carbon-based quantum dots seem to be a powerful tool in cancer diagnosis and treatment.
https://doi.org/10.1016/j.carbon.2022.11.026
Systemic administrations of water-dispersible single-walled carbon nanotubes: activation of NOS in spontaneously hypertensive rats. - In: Neurophysiology, ISSN 1573-9007, Bd. 52 (2020), 2, S. 101-109
Priority data have been obtained on the effects of repeated systemic administrations of water-dispersible single-walled carbon nanotubes (SWCNTs) to spontaneously hypertensive rats with respect to constitutive NO-synthase (cNOS). As is known, NO is an inhibitory transmitter in the cardiovascular system. It was found that the systemic (i.p., subcutaneous, and i.m.) introductions of SWCNTs during two weeks resulted in considerable elevations of the NO2- level (a marker of NO bioavailability) in the blood of experimental hypertensive animals. Thus, SWCNTs may be used in the future for antihypertensive therapy as a novel agent capable of activating cNOS and, thus, increasing the NO production in central and peripheral elements of the cardiovascular system.
https://doi.org/10.1007/s11062-020-09858-1
Boron-doped multi-walled carbon nanotubes as sensing material for analysis of dopamine and epinephrine in presence of uric acid. - In: Chemical physics letters, Bd. 710 (2018), S. 157-167
https://doi.org/10.1016/j.cplett.2018.09.007
Composite material based on hydroxyapatite and multi-walled carbon nanotubes filled by iron: preparation, properties and drug release ability. - In: Materials science & engineering, ISSN 1873-0191, Bd. 93 (2018), S. 606-614
https://doi.org/10.1016/j.msec.2018.08.019
Single-walled carbon nanotubes affect the expression of genes associated with immune response in normal human astrocytes. - In: Toxicology in vitro, ISSN 1879-3177, Bd. 52 (2018), 10, S. 122-130
https://doi.org/10.1016/j.tiv.2018.06.011
Synthesis and electrochemical characterization of nitrogen-doped and nitrogen-phosphorus-doped multi-walled carbon nanotubes. - In: Ionics, ISSN 1862-0760, Bd. 23 (2017), 8, S. 2025-2035
https://doi.org/10.1007/s11581-017-2049-2
Mikrofluidische Herstellung und Deutung der katalytischen Aktivität von Metallnanopartikeln für die Biohybridsynthese. - In: Technische Systeme für die Lebenswissenschaften, (2016), S. 631-632
Synthese und elektrochemische Anwendungen von modifizierten Kohlenstoffnanoröhren. - Ilmenau. - iv, 471 Seiten
Technische Universität Ilmenau, Habilitationsschrift 2016
Electrochemical response of nitrogen-doped multi-walled carbon nanotubes decorated with gold and iridium nanoparticles toward ferrocyanide/ferricyanide redox system. - In: Ionics, ISSN 1862-0760, Bd. 22 (2016), 10, S. 1957-1965
http://dx.doi.org/10.1007/s11581-016-1702-5
Electrochemical analysis of ascorbic acid, dopamine, and uric acid on nobel metal modified nitrogen-doped carbon nanotubes. - In: Sensors and actuators, ISSN 0925-4005, Bd. 231 (2016), S. 218-229
http://dx.doi.org/10.1016/j.snb.2016.03.032
Long-term stabilization of organic solar cells using hydroperoxide decomposers as additives. - In: Applied physics, ISSN 1432-0630, Bd. 122 (2016), 3, Article 255, insges. 6 S.
http://dx.doi.org/10.1007/s00339-016-9758-7
Der magnetoresistive Effekt von funktionalisierten Kohlenstoffnanoröhren :
Magnetoresistance of functionalized carbon nanotubes. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 47 (2016), 2/3, S. 254-262
http://dx.doi.org/10.1002/mawe.201600482
"Gast-Wirt"-Interkalat von doppelwandigen Kohlenstoff-Nanoröhren mit Tricarbonyl (cyclopentadienyl)-Mangan :
"Guest-host" intercalate of double-walled carbon nanotube with tricarbonyl (cyclopentadienyl)manganese. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 47 (2016), 2/3, S. 203-207
http://dx.doi.org/10.1002/mawe.201600477
Einwandige Kohlenstoff-Nanoröhren beeinflussen die Expression des CCND2-Gens in humanen U87 Glioma-Zellen :
Single-walled carbon nanotubes affect the expression of the CCND2 gene in human U87 glioma cells. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 47 (2016), 2/3, S. 180-188
http://dx.doi.org/10.1002/mawe.201600462
Long-term stabilization of organic solar cells using UV absorbers. - In: Journal of physics, ISSN 1361-6463, Bd. 49 (2016), 12, 125604, S. 1-7
http://dx.doi.org/10.1088/0022-3727/49/12/125604
Multi-walled carbon nanotubes doped with boron as an electrode material for electrochemical studies on dopamine, uric acid, and ascorbic acid. - In: Microchimica acta, ISSN 1436-5073, Bd. 183 (2016), 1, S. 35-47
https://doi.org/10.1007/s00604-015-1585-6
Properties and electrochemical characteristics of boron-doped multi-walled carbon nanotubes. - In: Chemical physics letters, Bd. 639 (2015), S. 217-224
https://doi.org/10.1016/j.cplett.2015.09.037
Application of multi-walled carbon nanotubes modified with boron oxide nanoparticles in electrochemistry. - In: Ionics, ISSN 1862-0760, Bd. 21 (2015), 11, S. 3087-3095
https://doi.org/10.1007/s11581-015-1496-x
Electrochemical studies on novel films consisting of phosphorus-doped multi-walled carbon nanotubes. - In: Ionics, ISSN 1862-0760, Bd. 21 (2015), 4, S. 1081-1088
http://dx.doi.org/10.1007/s11581-014-1277-y
Synthesis, characterization, and electrochemical application of phosphorus-doped multi-walled carbon nanotubes. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 19 (2015), 3, S. 891-905
http://dx.doi.org/10.1007/s10008-014-2696-4
Low-temperature 1 H NMR spectroscopic study of hydration properties of a hybrid system based on nanosilica, DNA and doxorubicin in the presence of C 60 fullerene. - In: Low temperature physics, ISSN 1090-6517, Bd. 40 (2014), 3, S. 239-245
http://dx.doi.org/10.1063/1.4866907
Long-term stabilization of organic solar cells using hindered phenols as additives. - In: ACS applied materials & interfaces, ISSN 1944-8252, Bd. 6 (2014), 21, S. 18525-18537
http://dx.doi.org/10.1021/am5024989
Nitrogen-doped multi-walled carbon nanotubes modified with platinum, palladium, rhodium and silver nanoparticles in electrochemical sensing. - In: Journal of nanoparticle research, ISSN 1572-896X, Bd. 16 (2014), 10, 2660, insges. 13 S.
https://doi.org/10.1007/s11051-014-2660-3
Multi-walled carbon nanotubes modified with gold nanoparticles with various diameters for the simultaneous analysis of dopamine and uric acid in a single experiment. - In: Sensor letters, ISSN 1546-1971, Bd. 12 (2014), 1, S. 153-159
http://dx.doi.org/10.1166/sl.2014.3231
Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 18 (2014), 9, S. 2555-2562
http://dx.doi.org/10.1007/s10008-014-2512-1
Disposable multiwalled carbon nanotube printed film electrochemical determination of acetaminophen, dopamine, and uric acid. - In: Analytical letters, ISSN 1532-236X, Bd. 47 (2014), 17, S. 2829-2843
http://dx.doi.org/10.1080/00032719.2014.926553
Non-enzymatic analysis of cholesterol in acetonitrile solutions. - In: Physics and chemistry of liquids, ISSN 1029-0451, Bd. 52 (2014), 2, S. 601-607
http://dx.doi.org/10.1080/00319104.2014.890895
Structure and electrochemical properties of aqueous suspensions of functionalized single- and multiwalled carbon nanotubes. - In: Ukrainian journal of physics, ISSN 2071-0186, Bd. 59 (2014), 4, S. 433-438
Influence of single-walled carbon nanotubes on thermal expansion of water. - In: International journal of thermophysics, ISSN 1572-9567, Bd. 35 (2014), 1, S. 19-31
http://dx.doi.org/10.1007/s10765-013-1552-6
Nitrogen-doped carbon nanotubes modified with gold nanoparticles for simultaneous analysis of N-acetylcysteine and acetaminophen. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 18 (2014), 3, S. 629-637
http://dx.doi.org/10.1007/s10008-013-2298-6
Speciation behavior of copper(II) acetate in simple organic solvents - revealing the effect of trace water. - In: European journal of inorganic chemistry, ISSN 1099-0682, (2014), 8, S. 1407-1412
http://dx.doi.org/10.1002/ejic.201400036
Electrocatalytic activity of nitrogen-doped carbon nanotubes decorated with gold nanoparticles. - In: Electrocatalysis, ISSN 1868-5994, Bd. 5 (2014), 1, S. 87-95
http://dx.doi.org/10.1007/s12678-013-0175-9
Voltammetric study on pristine and nitrogen-doped multi-walled carbon nanotubes decorated with gold nanoparticles. - In: Microchimica acta, ISSN 1436-5073, Bd. 181 (2014), 3/4, S. 329-337
https://doi.org/10.1007/s00604-013-1118-0
Influence of ozone on N-doped multi-walled carbon nanotubes. - In: Journal of experimental nanoscience, ISSN 1745-8099, Bd. 9 (2014), 4, S. 421-431
http://dx.doi.org/10.1080/17458080.2012.664792
Thermodynamic investigation of ferrocyanide/ferricyanide redox system on nitrogen-doped multi-walled carbon nanotubes decorated with gold nanoparticles. - In: Thermochimica acta, Bd. 576 (2014), S. 1-8
http://dx.doi.org/10.1016/j.tca.2013.11.020
Electrochemical sensor consisting of nitrogen-doped multi-walled carbon nanotubes decorated with platinum nanoparticles. - In: Advanced Electrochemistry, ISSN 2330-1554, Bd. 1 (2013), 2, S. 153-160
http://dx.doi.org/10.1166/adel.2013.1029
Effect of functionalization of nitrogen-doped carbon nanotubes on their electrochemical properties. - In: Advanced Electrochemistry, ISSN 2330-1554, Bd. 1 (2013), 2, S. 136-141
http://dx.doi.org/10.1166/adel.2013.1018
Multi-walled carbon nanotubes printed on thin textile films for electrochemical sensing. - In: Advanced Electrochemistry, ISSN 2330-1554, Bd. 1 (2013), 1, S. 67-74
http://dx.doi.org/10.1166/adel.2013.1014
Multi-walled carbon nanotubes printed onto polycarbonate substrate for electrochemical sensing. - In: Sensor letters, ISSN 1546-1971, Bd. 11 (2013), 8, S. 1465-1471
http://dx.doi.org/10.1166/sl.2013.2987
Nitrogen-doped multi-walled carbon nanotubes for paracetamol sensing. - In: Ionics, ISSN 1862-0760, Bd. 19 (2013), 12, S. 1897-1905
http://dx.doi.org/10.1007/s11581-013-0930-1
Printed one-time-use carbon nanotube-based films for sensing applications. - In: Sensor letters, ISSN 1546-1971, Bd. 11 (2013), 3, S. 596-602
http://dx.doi.org/10.1166/sl.2013.2761
Comparative study of membranotropic action of single- and multi-walled carbon nanotubes. - In: Journal of bioscience and bioengineering, ISSN 1347-4421, Bd. 115 (2013), 6, S. 674-679
http://dx.doi.org/10.1016/j.jbiosc.2012.12.016
Analysis of dopamine on printed polymer thin film consisting of multi-walled carbon nanotubes. - In: Monatshefte für Chemie, ISSN 1434-4475, Bd. 144 (2013), 5, S. 581-588
http://dx.doi.org/10.1007/s00706-012-0914-2
Der Einfluss der Bandstruktur auf die Elektronentransferkinetik von niedrigdimensionalem Kohlenstoff :
The role of band structure in electron transfer kinetics in low-dimensional carbon. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 44 (2013), 2/3, S. 226-230
http://dx.doi.org/10.1002/mawe.201300093
Electrochemical responses of carbon nanotubes-based films printed on polymer substances. - In: Ionics, ISSN 1862-0760, Bd. 19 (2013), 2, S. 335-341
http://dx.doi.org/10.1007/s11581-012-0729-5
Non-enzymatic analysis of glucose on printed films based on multi-walled carbon nanotubes. - In: Microchimica acta, ISSN 1436-5073, Bd. 179 (2012), 1/2, S. 157-161
We report on the fabrication of an enzyme-free electrochemical sensor for glucose based on a printed film consisting of multi-walled carbon nanotubes (MWCNTs). The MWCNT-based film can be produced by means of a flexographic printing process on a polycarbonate (PC) substrate. The electrochemical response of the MWCNT-based film (referred to as MWCNT-PC) towards the oxidation of glucose at pH 7 was studied by means of cyclic voltammetry and electrochemical impedance spectroscopy. The MWCNT-PC film exhibits substantial electrocatalytic activity towards the oxidation of glucose at an anodic potential of 0.30 V (vs. Ag/AgCl). The findings reveal that the MWCNT-PC film enables non-enzymatic sensing of glucose with a detection limit as low as 2.16 mu M and a sensitivity of 1045 mu Aa (TM) mM(-1)a (TM) cm(-2).
https://doi.org/10.1007/s00604-012-0881-7
Influence of concentration of supporting electrolyte on electrochemistry of redox systems on multi-walled carbon nanotubes. - In: Physics and chemistry of liquids, ISSN 1029-0451, Bd. 50 (2012), 5, S. 661-668
In the present work, the effect of the concentration of supporting electrolyte on the electrochemical behaviour of the redox couple ferrocyanide/ferricyanide, [Fe(CN)(6)](3-/4-) on film consisted of multi-walled carbon nanotubes (MWCNTs) was investigated. The MWCNTs were selectively grown on oxidised silicon substrate by means of catalytic chemical vapour deposition (CCVD) technique with decay of acetonitrile (ACN) in the presence of ferrocene (FeCp2) that served as catalysts. For the electrochemistry studies, the techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in three-electrode system were employed. The correlation between the solution's ionic strength and the electrochemical impedance parameters are discussed.
http://dx.doi.org/10.1080/00319104.2012.663496
Electrochemical responses and sensitivities of films based on multi-walled carbon nanotubes in aqueous solutions. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 41 (2012), 11, S. 2047-2057
http://dx.doi.org/10.1007/s10953-012-9925-1
Electrochemical and thermodynamic properties of hexacyanoferrate(II)/(III) redox system on multi-walled carbon nanotubes. - In: The journal of chemical thermodynamics, ISSN 0021-9614, Bd. 54.2012 (Nov.), S. 35-40
Novel films consist of multi-walled carbon nanotubes (MWCNT) were fabricated by means of catalytic chemical vapor deposition (CVD) technique with decomposition of either acetonitrile (ACN) or benzene (BZ) using ferrocene (FeCp2) as catalyst. The electrochemical and thermodynamic behavior of the ferrocyanide/ferricyanide, [Fe(CN)(6)](3-/4-) redox couple on synthesized MWCNT-based films was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques at T = (278.15, 283.15, 293.15, and 303.15) K. The redox couple [Fe(CN)(6)](3-/4-) behaves quasi-reversibly on fabricated MWCNT-based films and its reversibility is enhanced upon increasing temperature. Namely, the findings establish that with the rise in temperature the barrier for interfacial electron transfer decreases, leading, consequently, to an enhancement of the kinetics of the charge transfer process. According to thermodynamics the equilibrium of the redox process is shifted towards the formation of [Fe(CN)(6)](3-) at elevated temperatures.
http://dx.doi.org/10.1016/j.jct.2012.03.018
Water-soluble pristine fullerenes C60 increase the specific conductivity and capacity of lipid model membrane and form the channels in cellular plasma membrane. - In: Journal of biomedical nanotechnology, ISSN 1550-7041, Bd. 8 (2012), 3, S. 522-527
Im Titel ist "60" tiefgestellt
The aim of the present work was the investigation of the interaction of water-soluble pristine fullerenes C-60 with bimolecular lipid model membrane (BLM) and cellular plasma membrane (PM). The findings demonstrate that the fullerenes C-60 at low concentrations, namely in the concentration range of 1.0 x 10(-4)-1.0 mg . ml(-1), are preferentially incorporated into the hydrophobic region of BLM, increasing, thus, its specific conductivity and specific capacity. Furthermore, upon interaction of fullerenes C-60 with PM, pores or other type of local defects are formed, which are wide enough in order to permit the passage of water molecules across the cell membrane resulting to the externalization of phosphatidylserine from the inner to the outer PM leaflet.
http://dx.doi.org/10.1166/jbn.2012.1404
Oxidation of dopamine on multi-walled carbon nanotubes. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 16 (2012), 6, S. 2217-2226
Novel films consisting of multi-walled carbon nanotubes (MWCNTs) were fabricated by means of the chemical vapor deposition technique with decomposition of either acetonitrile (ACN) or benzene (BZ) in the presence of ferrocene (FeCp2) which served as catalyst. The electrochemical response of the two different kinds of MWCNT-based films, further referred to as MWCNT-ACN and MWCNT-BZ, towards the oxidation of dopamine (DA) to dopamine-o-quinone (DAQ) was tested by means of cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Both MWCNT-based films exhibit quasi-reversible response towards DA/DAQ with some slight kinetic differences; specifically, the charge-transfer process was found to be faster on MWCNT-ACN (k (s) = 35.3 × 10(-3) cm s(-1)) compared to MWCNT-BZ (k (s) = 6.55 × 10(-3) cm s(-1)). The detection limit of MWCNT-BZ for DA (0.30 mu M) appears to be poorer compared to that of MWCNT-ACN (0.03 mu M), but nevertheless, both MWCNT-based films exhibit greater detection ability compared to other electrodes reported in the literature. The sensitivities of MWCNT-ACN and MWCNT-BZ towards DA/DAQ were determined as 0.65 and 0.22 A M-1 cm(-2), respectively. The findings suggest that the fabricated MWCNT-based electrodes can be successfully applied for the detection of molecules with biological interest.
http://dx.doi.org/10.1007/s10008-012-1647-1
Structure-electrical resistivity relationship of N-doped multi-walled carbon nanotubes. - In: Journal of materials science, ISSN 1573-4803, Bd. 47 (2012), 5, S. 2390-2395
Nitrogen-doped multi-walled carbon nanotubes (N-MWCNT) were synthesized by means of catalytic chemical vapor deposition technique using acetonitrile as carbon source material and ferrocene as catalyst. The structure of the synthesized N-MWCNT was characterized by means of microscopic (SEM, HRTEM) as well as spectroscopic (FTIR, Raman) techniques. Furthermore, the specific resistivity and the electrochemical properties of N-MWCNT were investigated and compared with those of pristine MWCNT. The results are discussed in terms of structural differences between pristine MWCNT and N-MWCNT.
http://dx.doi.org/10.1007/s10853-011-6059-6
Multi-walled carbon nanotubes as electrode materials for electrochemical studies of organometallic compounds in organic solvent media. - In: Monatshefte für Chemie, ISSN 1434-4475, Bd. 142 (2011), 3, S. 233-242
Films of vertically aligned multi-walled carbon nanotubes (MWCNT) were selectively synthesized on silicon dioxide substrate by catalytic chemical vapor deposition using either benzene or acetonitrile as carbon source and ferrocene (1% w/w) as catalyst. The MWCNT were extensively characterized by using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy. In order to examine the prospective application of the fabricated MWCNT films for the detection of electro-active compounds in organic solvent media, electrochemical studies of the oxidation of cobaltocene (CoCp(2)) to cobaltocenium cation (CoCp (2) (+)) (Cp = cyclopentadienyl anion) in acetonitrile were performed on these films. For this purpose, cyclic voltammetry and electrochemical impedance spectroscopy were employed. The electrochemical parameters for the CoCp (2) (+/0) couple in acetonitrile were derived and compared with those obtained using a conventional glassy carbon electrode. The results demonstrate that the synthesized MWCNT films are promising electrode materials for the electrochemical detection of electro-active species in organic solvents. The MWCNT film formed upon decay of benzene has higher capacitance, less Warburg impedance, and less charge transfer resistance, and consequently it provides faster electron transfer kinetics.
http://dx.doi.org/10.1007/s00706-011-0454-1
Comparative study of mono- and dinuclear complexes of late 3d-metal chlorides with N,N-dimethylformamide in the gas phase. - In: Inorganic chemistry, ISSN 1520-510X, Bd. 50 (2011), 3, S. 771-782
Mono- and binuclear complexes of N,N-dimethylformamide (DMF) with chlorides of the divalent, late 3d metals M = Co, Ni, Cu, and Zn are investigated by means of electrospray ionization (ESI). Specifically, ESI leads to monocations of the type [(DMF)(n)MCl](+) and [(DMF)(n)M(2)Cl(3)](+), of which the species with n = 2 and 3 were selected for in-depth studies. The latter include collision-induced dissociation experiments, gas-phase infrared spectroscopy, and calculations using density functional theory. The mononuclear complexes [(DMF)(n)MCl](+) almost exclusively lose neutral DMF upon collisional activation with the notable exception of the copper complex, for which also a reduction from CuII to CuI concomitant with the release of atomic chlorine is observed. For the dinuclear clusters, there exists a competition between loss of a DMF ligand and cluster degradation via loss of neutral MCl(2) with decreasing cluster stability from cobalt to zinc. For the specific case of [(DMF)(n)ZnCl](+) and [(DMF)(n)Zn(2)Cl(3)](+), ion-mobility mass spectrometry indicates the existence of two isomeric cluster ions in the case of [(DMF)(2)Zn(2)Cl(3)](+) which corroborates parallel theoretical predictions.
http://dx.doi.org/10.1021/ic100759h
Clustering of palladium(II) chloride in acetonitrile solution investigated by electrospray mass spectrometry. - In: International journal of mass spectrometry, ISSN 1387-3806, Bd. 304 (2011), 1, S. 9-14
Solutions of palladium chloride in acetonitrile are investigated by means of electrospray ionization mass spectrometry (ESI-MS). In contrast to several other metal salts previously investigated using ESI-MS, PdCl(2)2 has a pronounced tendency for aggregation to yield [Pd(m)Cl(2m-1)(CH(3)CN)(n)](+) clusters in the positive ion mode and [Pd(m)Cl(2m+1)](-) clusters when the negative ions are sampled, respectively. The observation of these oligomers parallels polymeric structures of PdCl(2) in the solid phase. The positive ions are most abundant for m = 2 and generally associated with several molecules of the solvent, whereas many different cluster sizes occur for the anions which generally do not appear as solvent associates. Parallel conductivity measurements in the condensed phase lend support to a pronounced tendency for aggregation of PdCl(2) in acetonitrile solution.
http://dx.doi.org/10.1016/j.ijms.2011.02.014
Determination of impedance spectroscopic behavior of triphenylphosphine on various electrodes. - In: Analytical letters, ISSN 1532-236X, Bd. 44 (2011), 8, S. 1416-1430
The electrochemical oxidation of triphenylphosphine (Ph(3)P) was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) on glassy-carbon (GC), gold (Au) and multi-walled carbon nanotubes (MWCNT) in acetonitrile (ACN), dichloromethane (DCM), and cyclohexanone (CHN). The electron-transfer kinetics of the redox couple PPh(3)/Ph(3)P(center dot+) on various electrodes was found to increase with the order: Au < MWCNT < GC. The EIS results verify that GC provides faster charge-transfer kinetics since it affords less charge-transfer resistance and thus lower electron-transfer barrier from other electrodes tested. In DCM and CHN greater deviation from reversibility was observed which can be attributed to the poorer polarity of the solvents, which provides an additional barrier for the electron-transfer process.
http://dx.doi.org/10.1080/00032719.2010.520387
Application of films consisting of carbon nanoparticles for electrochemical detection of redox systems in organic solvent media. - In: Fullerenes, nanotubes & carbon nanostructures, ISSN 1536-4046, Bd. 19 (2011), 6, S. 505-516
In the present article, the electrochemical sensitivity and response of films consisting of carbon nanoparticles were examined to test their potential applications as electrode materials for the construction of electrochemical sensors. For this purpose, a film of vertically aligned multi-walled carbon nanotubes (MWCNTs) on silicon dioxide substrate was synthesized by means of catalytic chemical vapor deposition (CVD) at 900oC using ferrocene (FeCp2) as catalyst and acetonitrile (ACN) as a carbon source. Furthermore, bucky-paper (BP) film was produced upon ultrasonic treatment of aqueous solution of single-walled carbon nanotubes (SWCNTs) in the presence of sodium dodecyl sulfate (SDS) micelle. In order to examine the electrochemical activity of the fabricated films, electrochemical studies of the oxidation of ferrocene (FeCp2) to ferrocenium cation (FeCp2+) (where Cp denotes cyclopentadienyl anion) in ACN containing n-tetrabutylammonium hexafluorophosphat (NBu4PF6) as supporting electrolyte were performed. For the electrochemical experiments the techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed. The electrochemical parameters of the FeCp2+/0 redox couple in ACN on the fabricated films were determined and compared with those obtained using conventional glassy carbon (GC) electrode. The results demonstrate that the FeCp2+/0 redox couple exposes Nernstian response on either MWCNT or GC electrodes while its response on BP film can be recognized as near Nernstian. The findings verify that the synthesized MWCNT and BP films hold promising and important applications in electro-analytical chemistry.
http://dx.doi.org/10.1080/1536383X.2010.494782
Application of electrochemical impedance spectroscopy for characterisation of the reduction of benzophenone in acetonitrile solutions. - In: Physics and chemistry of liquids, ISSN 1029-0451, Bd. 49 (2011), 6, S. 729-742
http://dx.doi.org/10.1080/00319104.2010.508039
Electrochemistry on multi-walled carbon nanotubes in organic solutions. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 40 (2011), 9, S. 1645-1656
The oxidation of ferrocene (FeCp(2)) to ferrocenium cation were determined. On both electrodes tested, the electron transfer process was found to be quasi-reversible and diffusion controlled in all investigated solvent mixtures. The E (1/2) values were shifted toward less positive potentials with the enrichment of mixtures in MeOH, due probably to the larger Lewis basicity of the MeOH molecules. Furthermore, values of both D and k (s) diminish with the increase of MeOH content following the progressive increase of viscosity of the solvent medium. Among the electrodes probed, GC provides faster electrochemical process since it affords less charge-transfer resistance (R (ct)), and consequently, an insignificant barrier for interfacial electron transfer.
http://dx.doi.org/10.1007/s10953-011-9735-x
Thermodynamic studies on silver and thallium nitrate. - In: International journal of thermophysics, ISSN 1572-9567, Bd. 32 (2011), 9, S. 1950-1965
The molar conductivities (Lambda) of aqueous solutions of silver nitrate and thallium nitrate were measured in the temperature range from 291.15 K to 314.15 K. The Lambda values were analyzed using the Lee-Wheaton model, and the limiting molar conductivities (Lambda(o)) as well as the association equilibrium constants (K(A)) were derived. The center-to-center distances (alpha) of the formed ion pairs were considered to be equal to the Bjerrum's distance. The limiting ion conductivities (lambda(+/-)) were determined. The thermodynamic functions, Gibbs energy (Delta G(A)), enthalpy (Delta H(A)), and entropy (Delta S(A)) for the ion-pair formation process were determined as well. The results are discussed in terms of ion-ion and ion-solvent interactions.
http://dx.doi.org/10.1007/s10765-011-1046-3
MWCNT array electrodes as sensor materials for the detection of biomolecules. - In: Ukrainian-German Symposium on Physics and Chemistry of Nanostructures and on Nanobiotechnology, (2010), S. 195
O6.2.
Electrochemistry on multi-walled carbon nanotubes. - In: Ukrainian-German Symposium on Physics and Chemistry of Nanostructures and on Nanobiotechnology, (2010), S. 81
O2.5.
Electrochemical studies of the bis(triphenyl phosphine) ruthenium(II) complex, cis -[RuCl2(L)(PPh3)2], with L = 2-(2 -pyridyl)quinoxaline. - In: Journal of coordination chemistry, ISSN 1029-0389, Bd. 63 (2010), 20, S. 3517-3530
http://dx.doi.org/10.1080/00958972.2010.516362
Electrocatalytic properties of carbon nanotube carpets grown on Si-wafers. - In: Carbon, ISSN 1873-3891, Bd. 48 (2010), 15, S. 4489-4496
http://dx.doi.org/10.1016/j.carbon.2010.08.009
Electrochemical impedance spectroscopy and cyclic voltammetry of cis-[Cr(bipy)2(SCN)2]I (where bipy: 2,2'-bipyridine) in polar solvents. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 39 (2010), 6, S. 897-908
http://dx.doi.org/10.1007/s10953-010-9549-2
Synthesis and electrochemistry of multiwalled carbon nanotube films directly attached on silica substrate. - In: Journal of solid state electrochemistry, ISSN 1433-0768, Bd. 14 (2010), 6, S. 1101-1107
http://dx.doi.org/10.1007/s10008-009-0924-0
Electrochemical impedance spectroscopy and cyclic voltammetry of ferrocene in acetonitrile/acetone system. - In: Journal of applied electrochemistry, ISSN 1572-8838, Bd. 40 (2010), 2, S. 409-417
http://dx.doi.org/10.1007/s10800-009-0011-3
Complexation of late transition metal(II) ions (M = Co, Ni, Cu, and Zn) by a macrocyclic thiacrown ether studied by means of electrospray ionization mass spectrometry. - In: Rapid communications in mass spectrometry, ISSN 1097-0231, Bd. 23 (2009), 11, S. 1550-1556
http://dx.doi.org/10.1002/rcm.4035
Electrochemistry on multi-walled carbon nanotube films. - In: Chemické listy, ISSN 0009-2770, Bd. 103.2009, 15, S. s251
Electrochemical studies on cis-[Cr III (bipy) 2 (SCN) 2] I3 (where bipy denotes 2,2'-bipyridine) in acetonitrile. - In: Journal of solution chemistry, ISSN 1572-8927, Bd. 38 (2009), 12, S. 1536-1557
http://dx.doi.org/10.1007/s10953-009-9466-4
Can electrospray mass spectrometry quantitatively probe speciation? : hydrolysis of uranyl nitrate studied by gas-phase methods. - In: Inorganic chemistry, ISSN 1520-510X, Bd. 48 (2009), 13, S. 6287-6296
http://dx.doi.org/10.1021/ic900575r
Application of the extended Langmuir model for the determination of lyophobicity of 1-propanol in acetonitrile. - In: International journal of thermophysics, ISSN 1572-9567, Bd. 30 (2009), 3, S. 910-918
http://dx.doi.org/10.1007/s10765-009-0581-7
Conductometric and voltammetric studies on the bis(triphenyl phosphine) ruthenium(II) complex, cis-[RuCl2(L)(PPh3)2], where L: 2-(2'-pyridyl)quinoxaline. - In: Inorganica chimica acta, ISSN 0020-1693, Bd. 362 (2009), 9, S. 3079-3087
http://dx.doi.org/10.1016/j.ica.2009.02.005
Studies of ion solvation and ion association of n-tetrabutylammonium hexafluorophosphate and n-tetrabutylammonium tetraphenylborate in various solvents. - In: Fluid phase equilibria, ISSN 0378-3812, Bd. 277 (2009), 1, S. 20-28
http://dx.doi.org/10.1016/j.fluid.2008.11.004