Original scientific paper Characterization and electrocatalytic application of silver modified polypyrrole electrodes (original) (raw)
Related papers
Characterization and electrocatalytic application of silver modified polypyrrole electrodes
Journal of the Serbian Chemical Society, 2005
Silver modified polypyrrole electrodes were prepared with the aim of testing them for the electrooxidation of formaldehyde in alkaline solution. The modification of polypyrrole by immersion in aqueous AgNO 3 solution was studied by cyclic voltammetry and vacuum techniques (AES and XPS). The influence of time of immersion and the thickness of the polypyrrole film, prepared by electrochemical polymerization, on the modification of the polymer were examined. The results acquired from both electrochemical and spectroscopic examinations show that immersion of a polypyrrole electrode in a AgNO 3 solution results in its modification with silver, which is deposited in the elemental state on the surface. The quantity of silver deposited depends not only on the immersion time but also on the thickness of the polymer film. A modified PPy/Ag electrode exhibits catalytic activity for the electrooxidation of CH 2 O in NaOH. In spite of the low quantity of silver, the activity of the electrode for this reaction is comparable to that of a polycrystalline silver electrode.
Journal of Nanoparticles, 2015
A simple electrochemical method of synthesis of polypyrrole/silver (PPy/Ag) nanocomposite is presented. The method is based on potentiodynamic polymerization of pyrrole followed by electrodeposition of silver employing a single potentiostatic pulse. The synthesized PPy film has embedded Ag nanocubes. The morphology and structure of the resulting nanocomposite were characterized by field emission scanning electron microscopy and X-ray diffraction. Electron paramagnetic resonance studies showed that silver nanoparticle deposition on polypyrrole leads to an increase in carrier density, indicative of enhanced conductivity of the resulting composite. Electrocatalytic performance of the prepared composite was examined for reduction of hydrogen peroxide and was compared with corresponding PPy film and bare glassy carbon electrode.
Electrochimica Acta, 2020
Palladium-polypyrrole (Pd-PPy) composites synthesized via one-step and one-pot redox procedure have been tested as electrocatalysts for formaldehyde oxidation in aqueous solution under both inert and oxygen atmospheres. It has clearly been shown that inert electrode coated by the Pd-PPy composites demonstrates a high catalytic activity. Electrochemical response of Pd-PPy modified electrodes depends on the anodic potential range, pH and concentration of formaldehyde in solution as well as on the presence of oxygen in reaction atmosphere. It has been found that Pd-PPy composites are prospective materials for amperometric detection of formaldehyde in aqueous solution, even under oxygen atmosphere, as well as in the presence of methanol or/and formate-anions.
Russian Journal of Electrochemistry, 2017
Three alternative methods were developed for the synthesis of modifying palladium-polypyrrole layers on the surface of an inert electrode. Their electrocatalytic activity toward formaldehyde under inert atmosphere was checked. All the suggested methods are one-stage and allow synthesis of a film on the electrode surface from a solution containing a palladium salt and pyrrole in the absence of other active reagents. The electrochemical methods (potentiodynamic and double cathodic and anodic pulses techniques) in an aqueous medium give films with poorly reproducible electrocatalytic properties, while the chemical redox synthesis affords films with reproducibly high electroactivity toward methylene glycolate.
Electrocatalytic properties of polypyrrole in amperometric electrodes
Biosensors and Bioelectronics, 1991
The electrocatalytic oxidation of NADH, ascorbate, urate, xanthine and Hz02 at different polypyrrole electrodes has been investigated. The conducting polymer was grown on platinum, glassy carbon, or graphite electrodes and modified by means of enclosed redox-active anions or other redox-active compounds covalently bound to either the N-or the B-position of the pyrrole. Copolymers of pyrrole and N-substituted pyrrole derivatives of chloranil or 2,3-dichloro-L4naphthoquinone showed outstanding electrocatalytic properties for the oxidation of NADH. The application of these electrodes in amperometric steady-state measurements or flow-injection systems in combination with dehydrogenase reactions has been possible.
The incorporation of silver nanoparticles into polypyrrole: Conductivity changes
Silver nanoparticles obtained by the electro-exploding wire technique were used to deposit on polypyrrole films prepared electrochemically. The presence of silver nanoparticles deposited was confirmed by X-ray diffraction. Energy dispersive X-ray spectroscopy was used to estimate the amount of silver nanoparticles deposited on polypyrrole. The current-voltage characteristics obtained from scanning tunneling microscopy showed remarkable changes in the electrical and the electronic properties of polypyrrole, which was also observed by the conventional two-probe method. The new approaches are the novel process used to produce pure silver nanoparticles and the simple and clean electro-deposition without the use of any chemical agents.
Journal of the Chilean Chemical Society, 2006
Electroactive polypyrrole (PPy) films obtained under potentiostatic electropolimerization from aqueous solutions of pyrrole doped with sulfate (SO 4 2-) anions were modified by incorporation of copper (Cu) and silver (Ag) microparticles using electrochemical cementation process. The electrochemically deposited and dissolving processes metals (Cu and Ag) onto and from polypyrrole were investigated. The PPy-Cu and PPy-Ag electrodes were characterized by electrochemical techniques and scanning electron microscopy (SEM) analysis and the electrochemical response of these modified electrodes was compared to that of the unmodified polypyrrole electrode. The results indicate that two forms of metal, valence and elemental ones, can be formed on polypyrrole at a constant cathodic potential. However, only the valence metal can be left on polypyrrole at the anodic potential. The copper and silver particles interact with polypyrrole films involving a strong complex formation affecting its electrochemical behavior. Scanning electron microscopy measurements show that dendritic-like metal aggregates are formed on the film surface. The electrochemical experiments reveal that metal deposition on conducting polymer can be envisaged as an attractive method for the electrodes fabrication.
Materials Chemistry and Physics, 1996
Polypyrrole (Au/PPy) and polyaniline (Au/PAni) electrodes were prepared and their activities towards oxygen reduction in acid medium were examined. The insertion of iron or cobalt phthalocyanines into the conducting polymer during the electropolymerisation process was carried out and the modified electrodes were characterised by esr and uo-visible differential reflectance spectroscopies. The electrocatalytic behaviour of such electrodes towards oxygen reduction was examined. The influence of the central metal of the macrocycle and of the kind of polymer was investigated. It appears that the modified electrodes containing iron tetrasulfonated phthalocyanine are the most active ones but they are less stable than electrodes containing cobalt tetrasulfonated phthalocyanine. The comparison of the electrocatalytic behaviour of the Au/polymer-FeTsPc electrode with that of a bare platinum electrode towards oxygen reduction indicates that the reduction process is the same for both electrodes. The Au/polymer-FeTsPc electrode allows then to reduce the oxygen molecule mainly &I the 4-electron process into water as main product. In the case of the Au/polymer-CoTsPc electrode, the role of the conducting polymer in the whole reduction process is demonstrated. The Au/PAni-CoTsPc electrode allows to reduce the oxygen molecule mainly cia the 2-electron reaction into hydrogen peroxide, whereas the Au/PPyCoTsPc electrode allows it to reduce into water via the hydrogen peroxide formation for potentials lower than 0.4V rhe.
Journal of Solid State Electrochemistry, 2018
Silver(I) halide particles embodied in polypyrrole matrices are synthesized and further processed electrochemically to get nanoparticles of silver with significant activity in the surface-enhanced Raman spectroscopy (SERS) of the rhodamine 6G test solute, which is considered as a clear evidence of Ag nanocrystallization. The electrocrystallization of Ag nanoparticles is analyzed using redox charges of composites determined from cyclic voltammograms recorded at various time scales and/or cycle numbers. Pristine PPy/AgX and modified PPy/AgX/AgNP composites are characterized using electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray electron dispersive spectroscopy. The thermodynamic and kinetic conditions of the electrochemical modification of pristine polypyrrole-AgX composites leading to the electrocrystallization of Ag nanoparticles are discussed.
Graphite material is abundantly available from recyclable sources. It possesses a good electrical conductance property, which makes it an attractive material as a working electrode. However, due to a high activation overpotential it has limited applications as compared to other solid metal electrodes. In this present work, we obtained a graphite rod from a used battery, and carried out electrochemical improvements by electro-deposition with gold nanoparticles (AuNPs). The heterogeneous electron transfer rate and electron transfer resistance of the fabricated electrode were improved. The electrode overpotential has shown improvement by 50 mV, and the effective surface area has increased by 2 fold. To determine the practicability of the AuNPs/graphite electrode, we used the electrode in the analysis of myricetin. A squarewave voltammetry was used in the analysis, and the detection response increased by 2.5 fold, which suggested an improvement in the electrode sensitivity.