Electrochemical Behavior Of Ferrocene Research Articles

Electrochemistry characterization of ferrocene/ferricenium redox couple at glassycarbon electrode

In the present work the oxidation of ferrocene, , to the ferrocenium cation, , was examined in the solvents dichloromethane, and aqueous ethanol using the technique of cyclic voltammetry. The anodic (Epa) and the cathodic (Epc) peak potentials, as well as the corresponding anodic (ipa) and cathodic (ipc) peak currents, were obtained at different scan rates (0.05, 0.10, 0.30, 0.50 V.s-1). The diffusion coefficients (D) have been calculated using the Randles-Sevcik equation. The effects of changing the scan rate on the electrochemical behavior of ferrocene have been examined.Keywords: Cyclic voltammetry, diffusion coefficient, ferrocene, half-wave potential, Randles-Sevcik equation

Electrochemical behaviour of ferrocene in the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate, EMIMBF4, at 298 K

Electrochemical oxidation of ferrocene (Fc) at platinum and glassy carbon electrodes in the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate, EMIMBF4, has been studied by cyclic voltammetry (CV), convolutive potential sweep voltammetry (CPSV), chronopotentiometry (CP) and chronoamperometry (CA).On both electrodes, the electro-oxidation of ferrocene to ferrocenium (Fc+) takes place in a quasi-reversible electrochemical mode. The intrinsic rate constant of charge transfer, k0, and the charge transfer coefficient, α, have been calculated for the first time in the mentioned ionic liquid, by simulation of the cyclic voltammograms, logarithmic analysis of the convoluted curves and from the steady-state current potential curves by applying the Gauss–Newton non-linear square method. The diffusion coefficient of Fc has been also calculated by CV, CPSV, CP and CA. A two-way analysis of variance, ANOVA, has shown that with a 95% confidence level, there are no significant differences between the diffusion coefficients obtained with both electrodes by the different techniques.

The electrochemical behaviour of ferrocene in deep eutectic solvents based on quaternary ammonium and phosphonium salts

The electrochemical behaviour of ferrocene (Fc) is investigated in six different deep eutectic solvents (DESs) formed by means of hydrogen bonding between selected ammonium and phosphonium salts with glycerol and ethylene glycol. Combinations of cyclic voltammetry and chronoamperometry are employed to characterise the DESs. The reductive and oxidative potential limits are reported versus the Fc/Fc(+) couple. The diffusion coefficient, D, of ferrocene in all studied DESs is found to lie between 8.49 × 10(-10) and 4.22 × 10(-8) cm(2) s(-1) (these do not change significantly with concentration). The standard rate constant for heterogeneous electron transfer across the electrode/DES interface is determined to be between 1.68 × 10(-4) and 5.44 × 10(-4) cm s(-1) using cyclic voltammetry. These results are of the same order of magnitude as those reported for other ionic liquids in the literature.

Electrochemical Behaviour Of Ferrocene/Ferricinium Redox System In Pure And CO2 Saturated [C6MIM][PF6

The electrochemical behaviour of ferrocene has been studied in green solvent combining pure ionic liquid and CO2. Experimental results were achieved for the Fc/Fc+ (ferrocene/ferricinium ion) oxidation/reduction in pure and CO2 saturated 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) over the temperature range from 298.15 K to 323.15 K. Peak shaped voltammograms were obtained and usual electrochemical parameters were calculated in order to classify electron process at the electrode. Diffusion coefficients of electroactive species were determined in the order of 10-11 m2 s-1 using the Randles–Ševcík relationship. Mass transport was also favoured by both increases in temperature and dilution of CO2 in the media.

Electrochemical Behavior of Ferrocene in Various Ionic Liquids

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The electrochemical redox processes in methacrylate-based polymer electrolytes II. – Study on microelectrodes

The electrochemical behaviour of ferrocene was studied in different gel polymer electrolytes based on methyl, ethyl and 2-ethoxyethyl methacrylate and compared to the liquid aprotic solution (propylene carbonate). Voltammetric and chronoamperometric measurements on microelectrodes were conducted in order to describe the qualitative as well as quantitative behaviour of ferrocene in different conditions. Heterogeneous electron-transfer rate constants and diffusion coefficients of ferrocene in polymer electrolytes were estimated to be 1.1–7.8 × 10 −3 cm s −1 and 4–13 × 10 −8 cm 2 s −1 depending on the electrolyte composition. The influence of the polymer polarity, ferrocene concentration and level of polymer cross-linkage on the kinetics of ferrocene oxidation and its transport was discussed. The electrolytes with poly(2-ethoxyethyl methacrylate) exhibit the highest ionic conductivity (2–4 × 10 −4 S cm −1) as well as diffusion coefficient of ferrocene (1.3 × 10 −7 cm 2 s −1) in their structure.

Ferrocene as a Reference Redox Couple for Aprotic Ionic Liquids

AbstractThe electrochemical behavior of ferrocene has been studied in a number of room temperature ionic liquids. Diffusion‐controlled, well‐defined anodic and cathodic peaks were found for the Fc/Fc+ (ferrocene/ferrocenium) oxidation/reduction on the gold electrode. Ohmic resistance R between working and auxiliary electrodes was deduced from impedance measurements. Cyclic voltammograms were corrected for the base line current as well as for the ohmic drop (IR). The formal potential 1/2(Epa+Epc) for ferrocene reduction/oxidation in aprotic ionic liquids tested is within a relatively narrow range and may be approximated by the value of 0.527±0.018 V (against the cryptate Ag/Ag+222 in acetonitrile reference). Ferrocene diffusion coefficients, calculated from the peak current dependence on the sweep rate, were of the order of 10−7 cm2 s−1.

A novel hydrogen peroxide sensor based on the redox of ferrocene on room temperature ionic liquid film

A novel sensor was constructed based on the catalytic activity of ferrocene (Fc) that was immobilized on a room temperature ionic liquids (RTILs), 1-ethyl-3-methyl imidazolium tetrafluoroborate ([EMIM][BF 4]), film. Electrochemical behavior of ferrocene was investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A pair of stable, well-defined and quasi-reversible redox peak of ferrocene could be obtained at pH 7.0 phosphate buffer. Further investigations reveal that both anodic and cathodic peak currents of ferrocene vary linearly with the concentration of hydrogen peroxide (H 2O 2). Based on this, a new sensor for the measurement of H 2O 2 can be fabricated facilely. This sensor allowed us to measure H 2O 2 by polarizing the electrode under ether anodic or cathodic potential with an excellent stability and anti-interfering ability.

Electrolytic Behaviour of Ferrocene

Electrochemical behavior of ferrocene at platinum was studied in two solvents: acetonitrile and ethanol. Cyclic voltammetry showed that the electro-oxidation of ferrocene followed different routes in these two solvents. Anode process of aniline in acetonitrile under electrolytic conditions was also investigated in the presence of ferrocene.

Cyclic Voltammograms of Ferrocene on Multi‐Walled Carbon Nanotubes (MWCNTs)‐Modified Edge Plane Pyrolytic Graphite (EPPG) Electrode in Room Temperature Ionic Liquids (RTILs) of 1‐Ethyl‐3‐Methylimidazolium Tetrafluoroborate (EMIBF4)

AbstractIn this work, the electrochemical behavior of ferrocene (Fc) was investigated by cyclic voltammetry (CV) in room temperature ionic liquids (RTILs) of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF4) on glass carbon (GC), edge plane pyrolytic graphite (EPPG) and multi‐walled carbon nanotube (MWCNTs)‐modified EPPG electrodes, respectively. The results demonstrated that on GC electrode, pairs of well‐defined reversible peaks were observed, while for the electrode of EPPG, the peak potential separation (ΔEp) is obviously larger than the theoretical value of 59 mV, hinting that the electrode of EPPG is distinguished from the commonly used electrode, consistent with the previous proposition that EPPG has many “defects”. To obtain an improved electrochemical response, multi‐walled carbon nanotubes (MWCNTs) were modified on the electrode of EPPG; the increased peak current and promoted peak potential separation not only proved the existence of “defects” in MWCNTs, but also supported that “creating active points” on an electrode is the main contribution of MWCNTs. Initiating the electrochemical research of Fc on the MWCNTs‐modified EPPG electrode in RTILs and verifying the presence of “defects” on both EPPG and MWCNTs using cyclic voltammograms (CVs) of Fc obtained in RTILs of EMIBF4, is the main contribution of this preliminary work.

Cyclic Voltammetric Studies of Ferrocene in Nonaqueous Solvents in the Temperature Range from 248.15 to 298.15 K

In the present work the oxidation of ferrocene, Fe(C5H5)2, to the ferrocenium cation, Fe(C2H5)2 +, was examined in the solvents acetonitrile (ACN), acetone (ACE), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetanide (DMA), 3-pentanone (PEN), dimethyl sulfoxide (DMSO) and dichloromethane (DCM) over the temperature range from 248.15 to 298.15 K using the technique of cyclic voltammetry. The anodic (E pa) and the cathodic (E pc) peak potentials, as well as the corresponding anodic (i pa) and cathodic (i pc) peak currents, were obtained at different scan rates (0.02, 0.05, 0.08 and 0.10 V ·s–1). The half-wave potentials (E 1/2) of the Fe(C2H5)2 +/Fe(C5H5)2 couple in the investigated solvent media have been evaluated. The diffusion coefficients (D) have been calculated using the Randles-Sevcik equation. The effects of changing the scan rate, the temperature and properties of the solvent medium such as viscosity and donor number on the electrochemical behavior of ferrocene have been examined.

Temperature dependence of kinetics and diffusion coefficients for ferrocene/ferricenium in ammonium-imide ionic liquids

Abstract The electrochemical behavior of ferrocene (Fc) and ferricenium (Fc + ) was investigated by cyclic voltammetry with convolutional and semi-differential electroanalyses in the temperature range 298–373 K in the hydrophobic room temperature ionic liquid systems consisting of bis(trifluoromethanesulfone)imide anion with quaternary ammonium cation. The experimental results indicated that the redox reaction of Fc/Fc + was reversible in this ionic liquid and the charge-transfer rate constant ( k 0 ) has been obtained. Mass transport towards the electrode is a simple diffusion process and the diffusion coefficient ( D ) for Fc/Fc + has been also calculated. These results indicated that the k 0 and D increased with increasing temperature in ionic liquids. The validity of the Arrhenius law was verified by investigating the temperature dependences of k 0 and D .

The electrochemical behaviour of ferrocene in a photocurable poly(methyl methacrylate-co-2-hydroxylethyl methacrylate) film for a glucose biosensor

A single-step fabrication of a glucose biosensor with simultaneous immobilization of both ferrocene mediator and glucose oxidase in a photocurable methacrylic film consisting of poly(methyl methacrylate-co-2-hydroxylethyl methacrylate) was reported. The entrapped ferrocene showed reversible redox behaviour in the photocured film and no significant leaching of both entrapped ferrocene and enzyme glucose oxidase was observed because of the low water absorption properties of the co-polymer films. From electrochemical studies, ferrocene entrapped in the co-polymer film demonstrated slow diffusion properties. A linear glucose response range of 2–11 mM was obtained at low applied potential of +0.25 V. The glucose biosensor fabricated by this photocuring method yielded sensor reproducibility and repeatability with relative standard deviation of <10% and long-term stability of up to 14 days. The main advantage of the use of photocurable procedure is that biosensor membrane fabrication can be performed in a single step without any lengthy chemical immobilization of enzyme.

The Electrochemical Behavior of Ferrocene and Its Complex with DNA

The Electrochemical Behavior of Ferrocene and Its Complex with DNA

界面活性剤ミセル中の可溶化フェロセンの電気化学的挙動 フェリシニウムイオンと陰イオンミセル間の静電相互作用（原標題は英語）

界面活性剤ミセル中の可溶化フェロセンの電気化学的挙動 フェリシニウムイオンと陰イオンミセル間の静電相互作用（原標題は英語）

Electroanalysis oftert-Butylhydroquinone in Edible Oil at a Nafion-Coated Probe

An electrochemical probe consisting of co-planar platinum working and counter electrodes, and a silver quasi-reference electrode, was coated with a film of ionically conducting polymer, Nafion. The electrochemical behavior of ferrocene in a cooking oil could be observed at the probe without sample pretreatment. Hence it was demonstrated that the probe could be used to perform direct analysis of the antioxidant tert-butylhydroquinone (TBHQ) in edible oils. Using differential pulse voltammetry (DPV), a linear response to TBHQ was obtained across the concentration range 1–50 mg kg–1, with a sensitivity of 6.49×10–11 A kg mg–1; the detection time being 2 min for each assay. The limit of detection was 0.25 mg kg–1 (S/N=3). Interference from phenolic antioxidants such as tert-butylhydroxyanisole (BHA), tert-butylhydroxytoluene (BHT), propylene glycol, and propyl gallate was studied. BHA showed some interference at TBHQ:BHA ratios of 1:1 and 1:2. The others did not interfere. The mean recoveries of TBHQ spiked into samples of soybean, sunflower and palm oil were found to be 96%, 102% and 102%, respectively (n=5).

Application of SPE composite microelectrodes to the study of the spillover of adsorbed species on electrode surfaces

The electrochemical behavior of ferrocene in acetonitrile at the platinum|Nafion® interface was investigated using SPE composite microelectrodes. Two parallel reactions take place at the interface. The redox reaction of ferrocene|ferricinium ions predominates at the platinum|Nafion® composite microdisk electrode, while the adsorption or desorption of atomic hydrogen predominates at the platinum black|Nafion® composite powder microelectrode. This fact implies that the electrochemical reactions take place only at the interface and the adsorption of atomic hydrogen can occur on surface sites remote from the interface. The SPE composite microelectrode seems to be a potential technique of investigating the spillover of adsorbed species on the electrode surface.

An unusual electron-transfer behavior of ferrocene in aqueous microemulsion systems

The electrochemical behavior of ferrocene in an aqueous microemulsion (pentan-1-ol/sodium dodecyl sulfate (SDS)/aq. H 2SO 4) has been studied using an ultramicroelectrode. Contrary to the generally expected reversible peak, the experiments show the presence of a second oxidation peak during the reverse scan at low scan rates where the peak corresponding to ferricinium ion reduction is nearly absent along with the unanticipated appearance of a current dip. These observations are rationalized using a novel type of coupling between heterogeneous (electrochemical) and homogeneous (chemical) electron transfer processes. The composition of the medium, especially the acid concentration, affects the electron transfer of the solubilized probe and there exists a threshold acid concentration for achieving maximum anodic peak current.

Electrochemical Behavior of Ferrocene in Polyethylene Oxide‐400

The electrochemical behavior of ferrocene in polyethylene oxide‐400 was studied by cyclic voltammetry and large potential step chronoamperometry. Qualitative features and quantitative analyses of the experimental results in this large resistance polymeric solvents are presented. Temperature effects were described and from these an activation energy of ca.8 kcal/mol for the diffusion coefficient of ferrocene in polyethylene oxide‐400 was obtained. The effects of the supporting electrolytes on the diffusion coefficient and on the conductivity and viscosity of the polymeric solvent system are also described.

Voltammetric behavior of poly(vinylferrocene)

AbstractA voltammetric analysis of the electron‐transfer process in poly(vinylferrocene) (PVF) has been carried out; the results indicate that the electrochemical behavior of ferrocene and PVF are quite similar. The field effects in the macromolecular environment do, however, appear to influence the microscopic potential for oxidation of adjacent ferrocene residues in PVF. Analysis of the slopes of plots of limiting current versus the square root of the rotation speed indicate that only “isolated” ferrocene residues in the polymers are oxidized under the conditions of the rotating‐disk electrode experiment.Diffusion coefficients were determined experimentally for ferrocene and its macromolecular analogs were quite close to those simply calculated from the Stokes‐Einstein relationship. Further, it was demonstrated that the molecular weight, which is inversely proportional to the diffusion coefficient, could be determined by voltammetric techniques.