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
Pristine C60 fullerenes inhibit the rate of tumor growth and metastasis. - In: Experimental oncology, ISSN 1812-9269, Bd. 33 (2011), 3, S. 162-164
Im Titel ist "60" tiefgestellt
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
Structure and magnetic properties of multi-walled carbon nanotubes modified with cobalt. - In: Carbon, ISSN 1873-3891, Bd. 49 (2011), 13, S. 4443-4448
The magnetic properties of multi-walled carbon nanotubes (MWCNTs) modified with cobalt nanoparticles were studied in the temperatures and magnetic field range of (4.2-290) K and (0.03-5) T, respectively. Nanoparticles of cobalt encapsulated inside MWCNTs were obtained by using the chemical vapor deposition technique. The low temperature SQUID magnetization measurements were supplemented with structural investigations by means of high-resolution transmission electron microscopy, scanning electron microscopy as well as thermogravimetric and X-ray diffraction analysis. X-ray diffraction revealed the presence of MWCNTs, f.c.c. Co and h.c.p. Co phases. The magnetic characterization provided the remanent magnetization value (M(R)) of about 0.07 emu/g (similar to 40% of the saturation moment), while the coercive field (H(C)) value amounts to 600 Oe. Both parameters M(R) and H(C) slightly decrease with the rise of temperature. The substantial magnetization increase observed at low temperatures suggests the existence of nano Co clusters (in the atomic scale size).
http://dx.doi.org/10.1016/j.carbon.2011.06.039
Magnetic properties of multi-walled carbon nanotubes modified with cobalt. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 1, S. 29-32
Magnetic properties of multi-walled carbon nanotubes (MWCNT) modified with cobalt were studied in detail in the temperature range (4.2-290) K. MWCNT which encapsulate Co nanoparticles were obtained using CVD methods. The low temperature SQUID magnetization measurements were supplemented by structural investigations with thermogravimetric analysis, HRTEM and SEM.
http://dx.doi.org/10.1002/mawe.201100725
Low-frequency two-phonon modes step-like dispersion in resonance raman scattering of single-walled carbon nanotubes. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 1, S. 33-36
Single-walled carbon nanotubes (SWCNT) synthesized by the arc-discharge method were investigated by Raman spectroscopy in detail. In particular, the sharp peaks in (200.-400) cm(-1) spectral range of SWCNT, associated with low-frequency two-phonon modes, arising from flexural 2D graphite (graphene) ZO- (optical branch) and ZA- (acoustical branch) modes, have been firstly observed.
http://dx.doi.org/10.1002/mawe.201100726
Angewandte Nano-Bio-Systeme mit mikrofluidischen und biosensorischen Elementen für die dreidimensionale Zellkultur :
Applied nano bio systems with microfluidics and biosensors for three-dimensional cell culture. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 2, S. 139-146
http://dx.doi.org/10.1002/mawe.201100746
Photodynamic inactivation of mosquito iridovirus (MIV) by C 60 fullerenes. - In: Materials science and engineering technology, ISSN 1521-4052, Bd. 42 (2011), 2, S. 136-138
It was shown that water soluble C(60) fullerenes under visible light interact with iridovirus virions of mosquito Aedes flavescens and lead to their destruction. Specifically, the photodynamic inactivation of mosquito iridovirus during 1 h reduced the infectious virus titer in large wax-moth larvae Galleria mellonella on 4 lg ID50/ml. Therefore, for inactivation of iridoviruses in biological systems it is appropriate to use the photoexcited C(60) fullerenes.
http://dx.doi.org/10.1002/mawe.201100745