Cyclic Voltammetric Behavior Research Articles

Cyclic voltammetric behavior of crystal violet in aqueous solution: Correlation with dissolved states of cetyltrimethylammonium bromide

Cyclic voltammetric behavior of crystal violet in aqueous solution: Correlation with dissolved states of cetyltrimethylammonium bromide

Cyclic Voltammetric Behaviour and High-Performance Liquid Chromatography Amperometric Determination of Levamisole

The electrochemical oxidation of levamisole, a glassy carbon electrode, was investigated over the pH range 2.0–10.0. Cyclic voltammetric investigations showed a single oxidation process was recorded, with a peak potential (Ep) shown to be pH-dependent in the range 5.0–8.0; between pH 2.0 and pH 5.0, and above pH 8.0, the Ep was found to be independent of pH, indicating apparent pKa values of 5.0 and 8.0. Peak currents were found to increase with increasing pH values. This voltammetric oxidation process was found to be consistent with a two-electron, two-proton oxidation to the corresponding sulfoxide. Based on these findings, the development of a of method based on the high-performance liquid chromatography separation of levamisole, with electrochemical detection being used for its determination, was explored. The chromatographic conditions required for the separation of levamisole were first investigated and optimized using UV detection. The conditions were identified as a 150 mm × 4.6 mm, 5 µm C18 column with a mobile phase consisting of 50% methanol, and 50%, 50 mM, pH 8.0 phosphate buffer. The technique of hydrodynamic voltammetry was applied to optimize the applied potential required for the determination of levamisole, identified as +2.3 V versus a stainless-steel pseudo-reference counter-electrode. Under the optimized conditions, levamisole exhibited a linear response of 1.00–20 mg/L (R2 = 0.999), with a detection limit of 0.27 mg/L. The possibility of determining levamisole in artificial urine was shown to be possible via simple dilution in the mobile phase. Mean recoveries of 99.7%, and 94.6%, with associated coefficients of variation of 8.2% and 10.2%, respectively, were obtained for 1.25 µg/mL (n = 5) and 2.50 µg/mL (n = 5).

Simple and Intelligent Electrochemical Detection of Ammonia over Cuprous Oxide Thin Film Electrode

To realize simple and intelligent electrochemical ammonia (NH3) detection in water, highly dense colloidal copper nanoparticles (CuNPs) were prepared and subsequently deposited onto a glassy carbon electrode (GCE). The CuNPs/GCE was then placed in an oven at 60 °C to intelligently transform CuNPs into cuprous oxide (Cu2O) thin film. The colloidal CuNPs were characterized by ultraviolet-visible (UV-Vis) spectroscopy, whereas the fabricated Cu2O/GCE was subjected to Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The XRD of Cu2O/GCE showed the crystalline nature of the thermally converted Cu2O thin film, whereas XPS demonstrated that the thin film formed on the surface of GCE was primarily composed of Cu2O. The SEM images of Cu2O/GCE revealed Cu2O crystals with hexapod morphology. The EIS study exhibited substantially higher charger transfer activity of Cu2O/GCE compared to bare GCE. The drop coating of ammonia (NH3) solution onto Cu2O/GCE enabled the fabricated electrode to be utilized as an electrochemical sensor for NH3 detection in water. The cyclic voltammetric (CV) behavior of NH3/Cu2O/GCE was investigated in 0.1 M pH 7 phosphate buffer, which led to the formation of a copper-ammonia complex and revealed the nobility of the fabricated electrode. The square wave voltammetric (SWV) response was linear over the 10 µM and 1000 µM ranges with a detection limit of 6.23 µM and good reproducibility. The NH3/Cu2O/GCE displayed high selectivity for the detection of NH3 in the presence of various coexisting cations and anions in 0.1 M pH 7 phosphate buffer. The recovery of NH3 in the drinking water sample varied from 98.2% to 99.1%.

Demonstration of Feasibility Using Ionic Liquid as Electrolyte for Electrochemical Deposition and Recovery of Silver from Silver Oxide

Silver oxide (Ag₂O) is soluble in the hydrophobic protic amide-type ionic liquid (IL), protonated-betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]). Cyclic voltammetric behavior of Ag(I) showed a single redox couple, and NMR spectra implied that Ag⁺ might be coordinated with the [TFSA] anions in more extent than with the deprotonated [Hbet] ions (i.e. [bet]; a Zwitterion). By changing the scan rates and cycle numbers of potential scan utilized for the cyclic voltammetric electrodeposition, different particle sizes and distribution densities of silver nanoparticles (AgNPs) could be electrodeposited on glassy carbon disc electrode (GCE), which showed activities towards the electrochemical reduction of nitrate and oxidation of hydrazine, respectively, in alkaline solutions. The high faradic efficiencies (F.E.) of Ag electrodeposition using the contents of Ag₂O coin batteries as the Ag source implied that it may be possible to develop a process for recovering Ag from spent Ag₂O coin batteries based on the electrochemical system reported here.

An electrochemical reductive approach for selective determination of dopamine based on its reverse voltammetric preoxidation and intramolecular cyclization

In this paper, the cyclic voltammetric behavior of dopamine (DA) was investigated systematically at different potential windows on electrochemical reduce graphene oxide modified glassy carbon electrode, and we found that the electrochemical redox mechanism of DA is a multi-step ECE process and the redox peak appearing at low potentials (∼–0.30 V) was dependent on the oxidation of DA at high potentials (∼0.20 V). The electrolyte enriched with the DA preoxidation product was then analyzed by LC-MS/MS and its structure was identified as dopaminochrome (DC). So, we proposed a new insight for the non-oxidative electrochemical analysis of DA by reverse voltammetry preoxidation and intramolecular cyclization. Compared with the traditional forward scaning mode, the approach could minimize the interference of ascorbic acid (AA) and enable the dual quantitative analysis of DA in the presence of high concentration of AA with the linear range of 2.0 to 80 μM and 60 to 200 μM, respectively, and a detection limit of 1.0 μM. Furthermore, the voltammetric properties of norepinephrine (NE), epinephrine (EP), 3,4-dihydroxy-l-phenylalanine (l-DOPA), 4-O-methyldopamine (HMP) were also investigated. The similar voltammetric properties to DA of NE, EP, l-DOPA and HMP suggested that the proposed reverse voltammetric preoxidation method is generalizable and equally applicable to monoamine neurotransmitters with a catechol structure.

Construction of a logic gate sensitive monitoring system of Graphdiyne/Poly(N,N-dimethylacrylamide) binary structure films for environmental pollutant phenylhydrazine

In this work, binary hydrogel films based on Graphdiyne/Poly(N,N-dimethylacrylamide (GDY/PDEA) were successfully polymerized and assembled on pyrolytic graphite (PG) electrode surface. When phenylhydrazine (PHz) as an active electrochemical probe in solution exhibits reversible cyclic voltammetric (CV) behaviors in response to temperature, salt and pH at the membrane electrode. The CV signals of PHz were significantly enhanced by electrocatalysis of GDY layer of the films. And the mechanism of membrane reaction was discussed and studied. The presence of protonated PHz determines the pH-sensitive property of the system. During pH adjustment with esterase urease, in situ enzymatic electrocatalysis that may be accelerates the electron transfer rate at the electrode surface. The structural alterations of PDEA hydrogels under multiple conditions were attribute to the temperature response and salt concentration–response. GDY films can also have an effect on the CV response signals. In conclusion, a multi-stimulus response hydrogel film environmental sensor has been constructed, and a 5-input/5-output logic gate system including OR, AND and NOT has been successfully constructed. And constructed 2-to-4 decoder and 2-to-1 encoder two logic devices. It provides a new method to increase the complexity of the environmental pollutant monitoring calculation system.

Cyclic and Linear Sweep Voltammetric Studies of a Modified Carbon Paste Electrode with Nickel Oxide Nanoparticles toward Tamoxifen: Effects of Surface Modification on Electrode Response Kinetics.

Due to the serious adverse futures of some anticancer drugs, the determination of trace amounts of these drugs by simple analytical techniques is of great interest. In this regard, knowing about the mechanism of the analyte with the sensing material plays an important role. Nickel oxide nanoparticles (NiO NPs) modified by a carbon paste electrode (NiO-CPE) showed an irreversible cyclic voltammetric (CV) behavior in the NaOH (pH 13) supporting electrolyte based on the peak separation of 311 mV. Its peak current was decreased by adding tamoxifen (TAM), confirming that TAM molecules can consume NiO before participating in the electrode reaction. For this goal, TAM can be oxidized or reduced, and the corresponding mechanisms are schematically illustrated in the text. This study focused on the kinetic aspects of the process. Based on the CV results, a surface coverage (Γ) value of 2.72 × 10–5 mol NiO per cm2 was obtained with charge transfer coefficients αa and αc of 0.317 and 0.563, respectively. αa and αc values were changed to 0.08 and 0.72 in the presence of TAM. Further, the rate constant (ks) value was 0.021 ± 0.01 s–1 in the presence of TAM. In linear sweep voltammetry (LSV), an α value of about 0.636 ± 0.023 and an exchange rate constant (ko) value of about 0.097 ± 0.031 s–1 were obtained in the absence of TAM, which changed to 0.62 ± 0.081 and 0.089 ± 0.021 s–1 in the presence of TAM, respectively. Despite more published papers, when the TAM analyte was added to the NaOH supporting electrolyte, both anodic and cathodic peak currents of the modified NiO-CPE decreased. We suggested some reasons for this decreased peak current, and four mechanisms were illustrated for the electrode response in the presence of TAM.

Synthesis, Crystal Structure and Cyclic Voltammetric Behavior of N-aroyl-N′-(4′-cyanophenyl)thioureas

Herein, two title compounds, N-benzoyl-N′-(4′-cyanophenyl)thiourea (1) and N-(4-nitrobenzoyl)-N′-(4′-cyanophenyl)thiourea (2) were synthesized in a high yield, via different applications of aroyl isocyanate and 4-aminobenzonitrile. The structure of the prepared compounds was characterized by elemental analysis and FT-IR, 1H, and 13C-NMR spectroscopic methods. The crystal structure of the title compound 1 was determined by an X-ray single-crystal technique and an intramolecular C=O…H-N hydrogen bond and intermolecular C=S…H-N and C=S…H-C hydrogen interactions, which were observed for the crystal structure. The molecular electrostatic potential (MEP) and the Mulliken atomic charges of title compounds 1 and 2 were theoretically calculated and interpreted. Cyclic voltammetric (CV) experiments for the compounds were performed with the glassy carbon electrode. The reduction in potential values of the different functional groups such as nitro and cyano in title compounds were investigated using CV curves.

Effect of Thiourea Containing Composite Additives on Nickel Electrodeposition in Ammoniacal Solution

Composite additives have an important influence on the process of metal electrodeposition and the quality of a metal deposited layer. In this work, the additive thiourea (TU) was compounded with cetyltrimethyl ammonium chloride (CTAC), sodium dodecyl sulfate (SDS) and polyethylene glycol 20,000 (PEG20000), and their effect on the cyclic voltammetric behavior, electrochemical nucleation mechanism, crystallographic orientations and surface morphology of the nickel electrodeposition in ammoniacal solution were experimentally investigated. The results show that the introduction of composite additives resulted in a stronger cathodic polarization and increased the nucleation overpotential (NOP) values significantly, which had an important impact on forming compact and smooth nickel deposits. The chronoamperometry analysis indicated that the reduction in nickel followed the 3D progressive nucleation mechanism in the presence of composite additives at the step potential of −1.16 V and −1.18 V. Smoother and finer nickel films were found using scanning electron microscopy (SEM) images as the composite additives were used. X-ray diffraction revealed that all nickel deposit samples had the face-centered cubic structure, and five main crystal planes were displayed by the presence of composite additives in the electrolyte. Furthermore, the diffraction peaks of (111) and (200) crystal planes were slightly shifted toward lower 2θ values when thiourea was used in combination with additive CTAC or PEG20000. These results were beneficial for understanding the mechanisms and facilitating the rational design of additives for metal nickel electrodeposition.

A Rigidity/Flexibility Compatible Strategy to Improve the Stability and Durability of Flexible Electrochemical Sensor Based on a Polydimethylsiloxane Membrane Supported Prussian Blue@Carbon Nanotube Array

AbstractMechanical fatigue and mechanical‐chemical effect can harm the stability and durability of flexible electrochemical sensors and electronic devices. To solve the problem, we propose a rigidity/flexibility compatible strategy by implanting Prussian blue into the carbon nanotube array supported by polydimethylsiloxane (PDMS). The PDMS membrane is soft and flexible, and counteracts the external force; meanwhile, Prussian Blue@Carbon Nanotube Hybrid is hard and rigid for the reliable detection of hydrogen peroxide. Consequently, the cyclic voltammetric behavior of Prussian blue keep almost constant during the continuous bending experiments. The results indicate that the rigidity/flexibility compatible strategy is instructive to improve the performance of flexible electrochemical sensors and electronic devices.

Fabrication and Electrochemical Performance of TiO2-TiN/Sn-SnO2 Composite Films for High Capacity and High Conductivity Lib Anodes

Recently, anodic nanoporous TiO2 films have gained widespread attention as promising anode candidates for Li ion batteries to replace traditional C-based anodes. TiO2 delivers very small volume expansion (<4%) and works at a relatively high working voltage (1.7 V vs. Li/Li+) during Li+ insertion/extraction. This eliminates the influence from the solid electrolyte interface (SEI) layer and avoid the risk of lithium electrodeposition during charge/discharge process, thus further ensuring the cycling stability and safety of batteries. However, the development of TiO2 materials as LIB anodes is limited by its poor electric conductivity and low theoretical capacity. Therefore, we propose a new approach to fill Sn-based materials, which possess around 3 times theoretic capacity higher that the C-based anode, into the nanoporous anodic TiO2 films. Since the TiO2 nanostructure can alleviate the volume expansion of Sn-based materials, the synergistic effect of Sn with high capacity and TiO2 with large surface area is expected.In this study, we first formed nanoporous TiO2-TiN composite films on Ti foils by a smart anodization in NO3 –-based solutions. The inclusion of conductive TiN component in TiO2 matrix film improves the electronic conductivity effectively, which enables the successive electrodeposition on anodic TiO2 film. Then, the nanoporous TiO2-TiN composite films were used as matrix films to deposit Sn and/or SnO2 nanoparticles by a cathodic electrodeposition in acidic baths containing different Sn ions. The electric conductivity and nanostructures were tailored through anodizing process to perform successive electrodeposition. The microstructures, chemical composition, and crystalline structure of the anodized specimens before and after annealed were investigated FE-SEM (EDS), TEM (FIB), and XPS. Moreover, the cyclic voltammetric behaviors, impedance spectra, and charge-discharge performances of various composite films on Ti foils were investigated as binder-free anode materials for Li ion secondary batteries.Fig.1a-b shows the FE-SEM images of surface and cross section of TiO2-TiN composite films. An ordered nanoporous structure is obtained, with parallel pores of 50-100 nm in diameter and around 3-μm thickness after anodization for 90 min. Fig.1c shows the surface morphology of a TiO2-TiN/Sn composite film by electrodeposition in a Sn2+-based solution for 25 min. A granular Sn-based film with particle size of 100-300 nm in diameter formed on the anodic TiO2-TiN film. This indicates that the prolonged electrodeposition led to the filling of Sn not only inside but also on the anodic TiO2-TiN film. XPS analysis revealed that Sn deposits existed in metallic Sn and Sn oxides as SnO and/or SnO2. Moreover, it is confirmed by TEM observation that the nanocrystalline Sn-SnO2 deposits filled in the porous TiO2-TiN film. It is normally that the particles emerging on the film surface are larger than the pores of TiO2-TiN film.Fig.1d demonstrates the cycling performance and coulombic efficiency of TiO2-TiN/Sn-SnO2 and TiO2-TiN composite films on Ti sheets at 30 mA cm-2 for the first cycle and then 80 mA cm-2. The initial capacity of TiO2-TiN/Sn-SnO2 is 2100 μA h cm-2, which is around 5 times larger than the TiO2-TiN matrix film of 396 μA h cm-2. After 40 cycles, the capacity of the composite film remains 1153 μA h cm-2 and 4.6 times higher than the film without Sn electrodeposition. Since the nanoporous structure of TiO2-TiN can alleviate the volume expansion of Sn-based particles inside, the capacity deterioration can be mainly ascribed to the Sn-based particles overflowed on the surface, which may fall off or crush during charge/discharge process by the large volume expansion. Moreover, it was found from the EIS measurement that the internal electrical resistance of the TiO2-TiN composite film decreased considerably after the electrodeposition of the Sn-based materials, in proportional to the deposition time. Therefore, electrodeposition of Sn-based material in porous TiO2-TiN films is an effective approach to enhance the capacity and to improve the conductivity of the electrode material. Nevertheless, optimizing the conditions of anodization Ti base materials and Sn-based electrodeposition are necessary and will be an issue in the future study. Figure 1

Tungsten oxide decorated graphene oxide nanocomposite: Chemical synthesis, characterization and application in super capacitors

Nano structured metal oxides received considerable research attention due to their unique properties that can be used for designing advanced nanodevices. Thus, in the present study, Tungsten oxide/graphene oxide (WO3/GO) nanocomposite was synthesized, characterized and implemented in an electrochemical system. Graphene oxide was synthesized by Hummer’s method. WO3 doped Graphene oxide nanocomposite were also successfully synthesized using sodium tungstate as the source of Tungsten. The crystalline structure and optical properties of WO3 doped GO nanocomposite were characterized by UV–VIS spectroscopy, IR spectroscopy, X-ray diffraction (XRD) studies, Field Emission Scanning Electron Microscope (FESEM) with EDAX spectroscopy. The XRD spectrum showed diffraction peaks corresponding to the crystal planes of crystalline Tungsten oxide. Using Debye scherrer formula, the size of the undoped and Tungsten oxide doped Graphene oxide nanocomposite were also calculated. The morphological studies of the nanocomposite revealed crystal like morphology. The energy dispersive analysis confirmed the presence of Carbon, Tungsten and oxygen in the doped WO3/GO lattice. Cyclic voltammetric behaviour showed better electrochemical response with the doped sample when compared with the undoped sample.

New nickel (II) and copper (II) bidentate Schiff base complexes, derived from dihalogenated salicylaldehyde and alkylamine: Synthesis, spectroscopic, thermogravimetry, crystallographic determination and electrochemical studies

Nickel and copper metal complexes of bidentate Schiff base ligand (HL) were synthesized in methanolic solution from a condensation reaction of alkylamine (4-methoxyethylphenylamine) and dihalogenated salicylaldehyde (3,5-dichlorosalicylaldehyde). Their structures have been elucidated using various conventional spectroscopic techniques such as elemental analyses, nucleic magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, electronic spectroscopy and thermogravimetry analysis. The Schiff base nickel complex was characterized by X-ray structural analysis at 170 (2) K. This compound crystallizes in the triclinic space group P-1, with unit cell parameters: a = 6.233 (5)Å, b = 8.586 (5) Å, c = 15.247 (5)Å, β = 98.324 (5)°. Structural analysis of the ligand showed two coordinated centers through iminic nitrogen atom and phenoxy oxygen atom leading to a distorted square-planar geometry. The molar conductance values effectively confirmed the non-electrolytic nature of the both complexes. Ultraviolet visible (UV–Vis.) spectra were performed in order to resolve the expected π-π* and n-π* azomethine electronic transitions of the ligand and the both complexes. The thermal decomposition of the synthesized complexes was studied by thermogravimetry and differential thermogravimetry (TG/DTG) between 25 and 800 °C using four different heating rates 5, 10, 15 and 20 °C/min. Four methods from the literature have been chosen to estimate the values of the activation energies and the pre-exponential factors of the thermal decomposition; those of Kissinger, Ozawa, Friedman and Coats-Redfern. Thermodynamic parameters such as ΔS, ΔH and ΔG were determined by using the Coats-Redfern’s method. The electrochemical process was carried out by cyclic voltammetry (CV) in a tetrabutylammonium perchlorate (TBAP)/ dimethylformamide (DMF) 10-1 M as an electrolyte support. The prepared Schiff-base metal complexes displayed similar cyclic voltammetric behavior, exhibiting a quasi-reversible cathodic redox couple M(II)/M(I).

Comparative Electroanalytical Studies of Graphite Flake and Multilayer Graphene Paste Electrodes.

In this paper, the fabrication, surface characterisation and electrochemical properties of graphite flake (GFPE) and multilayer graphene (MLGPE) paste electrodes are described. The Raman investigations and scanning electron microscopy were used to analyze and compare structure of both carbon materials. The electroanalytical performance of both electrodes was examined and compared on the basis of the square-wave and cyclic voltammetric behavior of acetaminophen and model redox systems. Results of those studies revealed that GFPE has a larger electroactive surface area and better conductive properties, whilst MLGPE demonstrate better analytical characteristic in case of acetaminophen (AC) determination. AC determination was developed using square wave voltammetry (SWV) and square wave stripping voltammetry (SWSV). For both working electrodes, the process of accumulation enabled us to obtain an extended linear range and to lower the detection limit. In pharmaceutical formulations, AC was determined with good recovery.

Highly improved electrocatalytic oxidation of dimethylamine borane on silver nanoparticles modified polymer composite electrode.

Dimethylamine borane (DMAB) is a promising fuel alternative for fuel cell applications. In this work cyclic voltammetric behavior of DMAB was investigated on the polymerized aminophenol film decorated with Ag nanoparticles in alkaline media. The polymer film was formed on the glassy carbon electrode by electrochemical technique and then, the surface was modified with Ag nanoparticles. The surface of the modified electrode was identified by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy techniques. The developed electrode has displayed high electrocatalytic activity for DMAB oxidation in alkaline media depending on the supporting electrolyte concentration. Experimental parameters such as cycle number used in electropolymerization of p-aminophenol, deposition of Ag nanoparticles and supporting electrolyte were optimized.

Study on electrochemical properties of gelled electrolytes using nano fumed silica in the presence of some organic additives

A gelled electrolyte is made on the basis of liquid glass and sulphuric acid using nano fumed silica (NFS) in the presence of some other organic additives such as polyacrylamide (PAM) and polypropylene glycol (PPG). Lead-antimony alloy electrodes are prepared to examine the electrochemical properties of manufactured gelled electrolytes through cyclic voltammetric behaviour, electrochemical impedance and polarisation curves. The results from cyclic voltammetric diagrams show that the peak of lead solubility increases while the peak of oxygen evolution decreases due to using nano NFS for gelled electrolytes. Obtained Nyquist diagrams all show that the adsorption process occurs, in which the electrochemical impedance measured in the gelled electrolyte containing NFS increases in comparison with that without NFS. Observing the bigger slope of the outlet branch of oxygen in comparison with that of hydrogen on polarisation curves indicates that the rate of oxygen escape is stronger than that of hydrogen. The results also show that the oxygen overpotential increases while the hydrogen overpotential decreases slightly when NFS is present in gelled electrolytes.

High Diffusivity Coefficient of Cyclic Voltammetric Behaviour of Semicarbazones and Thiosemicarbazones and their Antimicrobial Studies

In this work, a series of N-hydroxy-2,6-diaryl-3-alkylpiperidin-4-one semicarbazones and thiosemicarbazones have been synthesized and also subjected towards cyclic voltammetric studies. The structure of reduced products was confirmed by FTIR, 1H &amp; 13C NMR spectral analysis. Further products were also screened for antimicrobial activities and it shows high significant effect towards Aspergillus niger among the eight tested fungal species. The propency towards order of reduced products is observed sharply and it was established that irreversible reduction of two electron transfers has taken for all four synthesized compounds and highly pH dependent. Among the synthesized compound, thiosemicarbzones showed versatile features with high diffusion coefficient value in minimum power consumption of current function.

Rapid electroanalytical procedure for sesamol determination in real samples

In this study, the development of an electroanalytical assay based on square wave voltammetry technique for determining sesamol (Ses) in sesame oil samples is described. The influence of various factors such as pH of the supporting electrolyte, its composition, and SW (square wave) parameters was studied. Linearity of the peak current depended on the concentration of Ses in the range from 3.0 to 140.0 μmol L−1 with a limit of detection of 0.71 μmol L−1. Furthermore, the cyclic voltammetric behavior of Ses and the effects of scan rate and pH on the peak current and peak potential of Ses were determined. Moreover, the electrode process was found to be diffusion-controlled. The proposed methodology was successfully applied for determining Ses in commercial sesame oil samples. The obtained results were in good agreement with the results from the HPLC-UV reference method.

Aqueous Route Synthesis of PAni Electrodes by Chemical Bath Deposition and Their Cyclic Voltammetric Analyses at Different Scan Rates

AbstractThe present work elaborates the aqueous route synthesis of polyaniline (PAni) electrodes for supercapacitors using chemical bath deposition (CBD) method and study of effective of scan rate on the cyclic voltammetric (CV) behavior. In the synthesis work, 1 m aniline and 1 m H2SO4 were taken in 2:2 ratio and kept for constant stirring and 1 m aqueous solution of (NH4)2S2O8 was added slowly in it. Stainless steel substrates were immersed in the reaction bath at room temperature for 1 h. The formation of PAni was confirmed by FT‐IR spectroscopic study. XRD analysis confirms the amorphous nature of the prepared PAni thin films. Contact angle study shows the hydrophilic behavior of the PAni electrodes. Obtained electrodes were subjected to cyclic voltammetric study at various scan rate from 5 to 100 mV s–1 in 1 m KOH electrolyte. Observed maximum specific capacitance was 516.34 F g–1 at 5 mV s–1 scan rate.

Electrochemical Sensor for the Determination of Alizarin Red-S at Non-ionic Surfactant Modified Carbon Nanotube Paste Electrode

The Cyclic Voltammetric (CV) behavior of Alizarin Red-S (ARS), which is an Anthraquinone dye was examined by utilizing TX-100 modified carbon nanotube paste electrode (TX-100MCNTPE). The surfactant utilized is TX-100, and it has been found that it has good electrocatalytic activity towards ARS. Distinctive parameters like pH, scan rate, detection limit have been studied in the potential range of 0.4 V to 1.0 V by using 0.2 M phosphate buffer solution (PBS) as supporting electrolyte. From these studies, it was clear that ARS shows well characterized irreversible oxidation peak in the solution of pH 6.5 at a scan rate of 0.1 V/s. Scan rate studies reveal that the entire process is adsorption controlled. Oxidation peak current rises linearly with the increase in the concentration of ARS. Two linear range is observed in the array of 2 × 10-6 to 10 × 10-6 M and 15 × 10-6 to 35 × 10-6 M. First linear range with a limit of detection (LOD) and limit of quantification (LOQ) of 1×10-6 and 3×10-6 M respectively was considered. The fabricated sensor can be productively employed for the simultaneous determination of ARS and Tartrazine (TZ).