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Redox Species (redox + species)

Distribution by Scientific Domains

Polymers and Materials Science	40%

Selected Abstracts

Heterogeneous Electron Transfer and Oxygen Reduction Reaction at Nanostructured Iron(II) Phthalocyanine and Its MWCNTs Nanocomposites

ELECTROANALYSIS, Issue 9 2010
Solomon
Abstract Electron transfer and oxygen reduction dynamics at nanostructured iron(II) phthalocyanine/multi-walled carbon nanotubes composite supported on an edge plane pyrolytic graphite electrode (EPPGE-MWCNT-nanoFePc) platform have been reported. All the electrodes showed the category 3 diffusional behaviour according to the Davies,Compton theoretical framework. Both MWCNTs and MWCNT-nanoFePc showed huge current responses compared to the other electrodes, suggesting the redox processes of trapped redox species within the porous layers of MWCNTs. Electron transfer process is much easier at the EPPGE-MWCNT and EPPGE-MWCNT-nanoFePc compared to the other electrodes. The best response for oxygen reduction reaction was at the EPPGE-MWCNT-nanoFePc, yielding a 4-electron process. [source]

Simulation of Redox-Cycling Phenomena at Interdigitated Array (IDA) Electrodes: Amplification and Selectivity

ELECTROANALYSIS, Issue 5 2008
M. Odijk
Abstract We present Finite Element Method (FEM) simulations of interdigitated array (IDA) electrode geometries to study and verify redox selectivity and redox cycling amplification factor. The simulations provide an adequate explanation of an earlier found, but poorly understood, high amplification factor (65×) in a 1,,m-spaced IDA microdevice. Moreover, using the FEM calculations we present selectivity measurements with IDA electrodes in a mixture of two redox species, as for example dopamine and ferricyanide. We show that it is possible to electrochemically detect dopamine in presence of the stronger reductor ferricyanide, which is impossible with direct amperometric detection, with the use of IDA electrodes with proper polarization potential of the collector electrode. Using our simulations, we show that a theoretical selectivity of dopamine over ferricyanide of 11 can be achieved. [source]

Nitrate-Selective Solid Contact Electrodes with Poly(3-octylthiophene) and Poly(aniline) as Ion-to-Electron Transducers Buffered with Electron-Ion-Exchanging Resin

ELECTROANALYSIS, Issue 13-14 2006
Galina
Abstract The study of nitrate selective solid contact electrodes containing poly(3-octyl)thiophene and poly(aniline) demonstrated the advantage of buffering the transducing layer with electron-ion-exchanging resin. The buffering, in particular in the case of poly(aniline) doped with nitrate anions ensured significant improvement of the long-term stability and piece-to-piece reproducibility of the electrode potentials. It is shown that the redox species causes potential drift after a long time delay, probably because of slow diffusion in the membrane bulk. [source]

Preparation, Structure, and Electrochemical Properties of Reduced Graphene Sheet Films

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009
Longhua Tang
Abstract This paper describes the preparation, characterization, and electrochemical properties of reduced graphene sheet films (rGSFs), investigating especially their electrochemical behavior for several redox systems and electrocatalytic properties towards oxygen and some small molecules. The reduced graphene sheets (rGSs) are produced in high yield by a soft chemistry route involving graphite oxidation, ultrasonic exfoliation, and chemical reduction. Transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy clearly demonstrate that graphene was successfully synthesized and modified at the surface of a glassy carbon electrode. Several redox species, such as Ru(NH3)63+/2+, Fe(CN)63,/4,, Fe3+/2+ and dopamine, are used to probe the electrochemical properties of these graphene films by using the cyclic voltammetry method. The rGSFs demonstrate fast electron-transfer (ET) kinetics and possess excellent electrocatalytic activity toward oxygen reduction and certain biomolecules. In our opinion, this microstructural and electrochemical information can serve as an important benchmark for graphene-based electrode performances. [source]

Ultrathin Carbon Nanotube Mat Electrodes for Enhanced Amperometric Detection

ADVANCED MATERIALS, Issue 30 2009
Ioana Dumitrescu
A cCVD method for producing transparent, conducting carbon nanotube (CNT) mats of near complete surface coverage is described. Disk-shaped UMEs using the CNT mats reveal reversible electrochemistry for outer sphere redox species and remarkably low capacitance. CNT mat UMEs can be used for the electrochemical detection of dopamine at micromole concentrations in albumin solution, with no decrease in electrode performance even after extensive use. [source]