Cyclic Voltammetry Techniques Research Articles

Dibenzothiophene Bridged Bis‐Bodipy and Bis‐Metal Dipyrrin Complexes

AbstractDibenzothiophene (DBT) bridged bis‐dipyrromethane was synthesized by treating readily available 4,6‐di(p‐formylphenyl) dibenzothophene with pyrrole under acid catalyzed conditions. The DBT bridged bis‐dipyrromethane was further oxidized with DDQ to afford the DBT bridged bis‐dipyrrin which was used as a ligand to prepare DBT bridged bis‐BODIPY, bis‐Ni(II) dipyrrin and bis‐Pd(II) dipyrrin complexes by treating the ligand with BF3 ⋅ Et2O, Ni(acac)2 and Pd(acac)2 respectively under mild reaction conditions. The DBT‐bridged bis‐BODIPY and bis‐metal dipyrrin complexes were thoroughly characterized and studied by HR‐MS, 1D & 2D NMR, absorption, fluorescence, cyclic voltammetry and DFT techniques. The bis‐BODIPY and bis‐Pd(II) dipyrrin showed highly intense absorption band at ~500 nm along with one low intense absorption band at 340 nm whereas the bis‐Ni(II) dipyrrin complex showed slightly broadened blue shifted high intense band at 490 nm along with one additional band at 426 nm. The bis‐BODIPY was fluorescent with fluorescence band at 524 nm and quantum yield of 0.031 whereas bis‐M(II) dipyrrin complexes were nonfluorescent. DFT optimized structures revealed that the BODIPY units are more planar with the dibenzophene moiety in bis‐BODIPY with an angle of ∼5.68°. However, in 3‐Pd and 3‐Ni, the M(II)‐dipyrrin units are much more deviated from the dibenzothiophene plane with an angle of 12.81°–14.23°.

Voltammetric determination of hydrogen peroxide at decorated palladium nanoparticles/poly 1,5-diaminonaphthalene modified carbon-paste electrode.

In this work, palladium nanoparticles (PdNPs)/p1,5-DAN/ carbon paste electrode (CPE) and p1,5-DAN/CPE sensors have been developed for determination of hydrogen peroxide. Both sensors showed a highly sensitive and selective electrochemical behaviour, which were derived from a large specific area of poly 1,5 DAN and super excellent electroconductibility of PdNPs. PdNPs/p1,5-DAN/CPE exhibited excellent performance over p1,5-DAN/CPE. Thus, it was used for detecting hydrogen peroxide (H2O2) with linear ranges of 0.1 to 250 µM and 0.2 to 300 µM as well as detection limits (S/N = 3) of 1.0 and 5.0 nM for square wave voltammetry (SWV) and cyclic voltammetry (C.V) techniques, respectively. The modified CPE has good reproducibility, adequate catalytic activity, simple synthesis and stability of peak response during H2O2 oxidation on long run that exceeds many probes. Both reproducibility and stability for H2O2 detection are attributable to the PdNPs immobilized on the surface of p1,5-DAN/CPE. The modified CPE was used for determining H2O2 in real specimens with good stability, sensitivity, and reproducibility.

Determination of glyphosate using electrochemical aptamer-based label-free voltammetric biosensing platform

Glyphosate is currently the most frequently used herbicide in the agricultural industry. Due to its widespread usage, there are concerns about its potential toxicity when it contaminates water, soil, and agricultural products. In this study, a simple aptamer-based biosensor was developed to detect glyphosate. The electrode surfaces were modified by reducing diazonium salts during electrodeposition and forming carboxylic acid groups. The immobilization of aminoated glyphosate aptamers on the electrode surface was then carried out using a carbodiimide reaction between the amino and carboxylic acid groups. The electrochemical cell circuit was completed using an analyte and redox probe solution on the electrode surface. Cyclic voltammetry, differential pulse, and electrochemical impedance spectroscopy techniques were then explored to investigate their potential as biosensors. Upon exposure to glyphosate, the spatial conformation of the specific aptamer used is altered, which generates an electrochemical response that can be quantified. Glyphosate could be quantified using voltammetry in the 1 to 5000 nM range, with a 0.67 nM detection limit. Furthermore, the constructed aptasensor demonstrated significant selectivity for glyphosate in the presence of interfering substances like glycine, dimethoate, and alanine. This biosensor has considerable potential for evaluating glyphosate in actual samples because of its simple design, high sensitivity, and rapid functionality. Moreover, developing a simple, cost-effective, and portable device for field applications may be possible.

Green voltammetric method for determination of diclofenac sodium in environmental and biological samples using aluminium tungstate nanoparticles modified carbon paste electrode

ABSTRACT Based upon aluminium tungstate (Al2(WO4)3 NPs), a new modified sensor was created in order to monitor diclofenac sodium (DCF) electrochemically in environmental samples. The electrode composition, electrolyte effect, selectivity, scan rate, and pH parameters that affect the assay’s performance were optimised and the pH study revealed that pH 3.6 was found to be suitable to improve the electrochemical behaviour of diclofenac. The electrochemical characteristics of the built-in electrode were assessed using cyclic voltammetry technique (CV).The electrode composition, electrolyte effect, selectivity, scan rate, and pH parameters were optimised. The limit of detection was found to be 0.076 µM and the limit of quantification (LOQ) value was 0.25 µM for the concentration range (0.2–25 µM) of DCF. It has demonstrated good selectivity for (DCF) in presence of the interfering species and its electrochemical sensing’s repeatability, reproducibility and stability were evaluated and found typical. Some environmental samples like tap water, waste water, Nile-river water and biological ones like urine and plasma, have been effectively applied using the proposed electrochemical sensor. Green chemistry metrics, viz. Analytical GREEnness Preparation (AGREEprep), Analytical Eco-Scale Assessments (ESA) and The AMVI for the proposed method were calculated and have assured that the method has limited negative impact on both human health and the environment.

Electrosynthesis of Verdoheme and Biliverdin Derivatives Following Enzymatic Pathways.

Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing polypyrrole frameworks, have inspired catalyst designs to address energy and environmental challenges. Despite remarkable progress in benchtop synthesis of verdoheme and biliverdin derivatives, all reported syntheses, starting from metalloporphyrins or inaccessible biliverdin precursors, require multiple steps to achieve the final desired products. Additionally, such synthetic procedures use multiple reactants/redox agents and involve multistep purification/extraction processes that often lower the yield. However, in a single step using atmospheric oxygen, heme oxygenases selectively generate verdoheme or biliverdin from heme. Motivated by such enzymatic pathways, we report a single-step electrosynthesis of verdoheme or biliverdin derivatives from their corresponding meso-aryl-substituted metalloporphyrin precursors. Our electrosynthetic methods have produced a copper-coordinating verdoheme analog in >80% yield at an applied potential of 0.65 V vs ferrocene/ferrocenium in air-exposed acetonitrile solution with a suitable electrolyte. These electrosynthetic routes reached a maximum product yield within 8 h of electrolysis at room temperature. The major products of verdoheme and biliverdin derivatives were isolated, purified, and characterized using electrospray mass spectrometry, absorption spectroscopy, cyclic voltammetry, and nuclear magnetic resonance spectroscopy techniques. Furthermore, X-ray crystallographic data were collected for select cobalt (Co)- and Cu-chelating verdoheme and metal-free biliverdin products. Electrosynthesis routes for the selective modification at the macrocycle ring in a single step are not known yet, and therefore, we believe that this report would advance the scopes of electrosynthesis strategies.

Structural and electrochemical properties of a Cu(I) Schiff-base complex: Catalytic application to the synthesis of tetrahydropyrimidine derivatives

Herein, we report the synthesis and spectroanalytical characterization of one-dimensional polymeric Cu(I) complex [Cu(L2Br)I]n, incorporating N,N′-bis(2-bromobenzylidene)ethane-1,2-diamine Schiff base ligand, L2Br. Single crystal X-ray diffraction (SC-XRD) was used to examine the specific organization of atoms in thecomplex. The results showed that the Cu ion was coordinated only throughthe N donor sitesof the Schiff base. The complex’s tetrahedral shape was distorted, as demonstrated by the bond angles around the metal atom. The natural bond orbital and atoms in molecules investigations were also carried out in order to gain greater knowledge of the Cu(I) complex’s intermolecular charge transfer characteristics. The redox nature of the the complex was assessed by the cyclic voltammetry (CV) technique. The Cu(I)/Cu(II) redox arrangement has been observed to exhibit characteristics consistent with a quasi-reversible method. Furthermore, the catalytic activity of the Cu(I) complex was executed in the first-time synthesis of new tetrahydropyrimidine derivatives by treating various aryl nitriles with 2,2-dimethyl-1,3-propanediamine under conventional thermal conditions. A mechanism for the catalytic reaction was suggested and investigated by density functional theory (DFT).

Mo6+ bifunctional substitution of P2-type manganese oxide for high performance sodium-ion batteries

Due to its cost-effectiveness and high specific capacity, P2-type manganese (Mn) oxide is considered a highly promising cathode material for sodium ion batteries (SIBs). However, the practical application of this material is hindered by poor cyclic stability caused by the phase transition of P2-P’2 due to the Jahn-Teller effect of Mn3+ at low voltage and significant volume changes at high voltage. In this study, we utilized Mo6+ dual-function P2-Na0.67Mn0.99Mo0.01O1.997(PO4)0.0008 (NMMPO-1) to achieve exceptional magnification performance and cycle stability. Advanced electron microscopy and X-ray diffraction analysis revealed that Mo6+ acts as a pillar in replacing interlayer Na+ sites within the P2 phase, resulting in extended layer spacing and a stable crystal structure. Additionally, Mo6+ substitution for Mn3+ weakens the Jahn-Teller distortion effect of Mn3+. Ex-situ X-ray diffraction experiments demonstrated that NMMPO-1 effectively inhibits the P2-P’2 phase transition at low voltage while minimizing volume changes during charge–discharge cycles. Overall, our modified NMMPO-1 exhibits excellent cycle stability with 144.55 mA h g−1 after 100 cycles at 0.5C, retaining 83 % capacity retention rate, along with impressive rate performance achieving capacity of 100.57 mA h g−1 at 5C. Furthermore, NMMPO-1 demonstrates superior air stability compared to unmodified samples when exposed to air over multiple cycles. Moreover, through detailed analysis using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic intermittent titration technique (GITT) curves; it is observed that NMMPO-1 possesses enhanced Na+ diffusion capacity and kinetic properties compared to other materials. This research provides novel insights into the role of substituting high valence cations in layered Mn oxide materials which can contribute towards designing improved performance for future sodium ion battery applications.

Establishing a new efficiency descriptor for methanol oxidation reaction and its validation with commercially available Pt‐based catalysts

AbstractDirect methanol fuel cells (DMFCs) have received a lot of attention in recent years as promising technology for generating clean and efficient energy. In DMFC, the anode catalyst is a vital component because it is involved in the oxidation of methanol, which produces electrons that can be used as an energy source. Cyclic voltammetry (CV) is commonly used to test the characteristics of the electrode materials before they are employed in the actual fuel cell. Interestingly in the case of DMFCs CV also is a useful technique to obtain vital information about the performance and expected efficiency of the electrodes. In general, the CV of methanol electrooxidation for Pt‐based catalysts has two peaks, If in the forward scan (anodic scan) and Ib in the backward scan (cathodic scan). The ratio of these two peaks (If/Ib) is the most commonly used criterion for investigating CO poisoning in catalysts. However, there is a great deal of ambiguity surrounding this criterion, owing to the genesis of Ib. Addressing this we present here a new criterion to evaluate the efficiency of the catalyst using the same CV technique. We validate this newly proposed criterion with commercial Pt/C (comm. Pt/C) and other commercially available alloy catalysts.

A novel L-Cysteine voltammetric sensor based on a dual-nucleation copper (II) complex

A novel platform of simple and cost-effective carbon paste electrode (CPE)-modified with a binuclear copper (II)-8-hydroxyquinoline complex was used for catalytic electroxidation of L-Cysteine. The modified electrode described was observed to significantly reduce the electrooxidation potential of L-Cysteine. Electrochemical impedance spectroscopy confirmed a significant decrease in the charge transfer resistance at the electrode surface by introducing the binuclear copper complex in the CPE. It was proposed that the two molecules of cysteine, adsorbed to the modified electrode surface, are oxidized to a cystine molecule via copper (II) centers of the complex which are consequently reduced to copper (I) species, responsible for the voltammetric peak observed when the potential was scanned toward the positive direction. To improve the electrode signal for cysteine, the electrode composition was also optimized. Two electrochemical techniques of cyclic voltammetry and amperometry were applied for the establishment of the calibration curve for cysteine determination by this electrode. The linear ranges of the calibration curves are obtained utilizing two electrochemical techniques of cyclic voltammetry and amperometry were 286–5000 μM and 11.6–500 μM, respectively. Also, the detection limits of cysteine assay by the above-cited techniques were calculated and equal to 86.7 μM and 3.5 μM, respectively. The electrode described was applied for cysteine determination in some vegetable samples which showed satisfactory results. Also, the selectivity of the sensor was checked against some biomolecules and amino acids such as Glycine, Alanine, Arginine, Methionine, Glucose, Urea, BrO3- and Citric acid. The introduced sensor exhibited excellent selectivity for cysteine determination in food samples.

Designing a Phenalenyl-Based Dinuclear Ni(II) Complex: An Electrocatalyst with Two Single Ni Sites for the Oxygen Evolution Reaction (OER).

A new dinuclear Ni(II) complex 1, [Ni2II(dtbh-PLY)2], is synthesized from 9-(2-(3,6-di-tert-butyl-2-hydroxybenzylidene)hydrazineyl)-1H-phenalen-1-one, dtbh-PLYH2 ligand, and structurally characterized by various analytical tools including the single-crystal X-ray diffraction (SCXRD) technique. In the solid state, both Ni(II) metal centers in complex 1 exist in a distorted square planar geometry and display the presence of rare Ni···H-C anagostic interactions to form a one-dimensional (1-D) linear motif in the supramolecular array. Complex 1 is further stabilized in the solid state by π-π-stacking interactions between the highly delocalized phenalenyl rings. The redox features of complex 1 have been analyzed by the cyclic voltammetry (CV) technique in solution as well as in the solid state, revealing the crucial involvement of both the Ni(II) metal centers for undergoing quasi-reversible oxidation reactions on the application of an anodic sweep. A complex 1-modified glassy carbon electrode, GC-1, is employed as an electrocatalyst for oxygen evolution reaction (OER) in 1.0 M KOH, giving an OER onset at 1.45 V, and very low OER overpotential, 300 mV vs the reversible hydrogen electrode (RHE) to reach 10 mA cm-2 current density. Furthermore, GC-1 displayed fast OER kinetics with a Tafel slope of 40 mV dec-1, a significantly lower Tafel slope value than those of previously reported molecular Ni(II) catalysts. In situ electrochemical experiments and postoperational UV-vis, Fourier transform infrared (FT-IR), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) studies were performed to analyze the stability of the molecular nature of complex 1 and to gain reasonable insights into the true OER catalyst.

Aminosilane assisted deposition of gold nanoparticles on Zn(OH)2 nanosheets and their application in electrochemical sensor

A facile and efficient method for systematical deposition of gold nanoparticles (AuNPs) on Zn(OH)2 nanosheets (NS) with different Zn and Au ratios was established in the presence of N-[3-(trimethoxysilyl)propyl]diethylenetriamine (TPDT silane), without adding any external reducing agents, at room temperature. Here, TPDT silane behaves as both a stabilizing and reducing agent. UV–vis absorption spectroscopy, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy were used to confirm the formation of AuNPs on Zn(OH)2 NS. As the concentration of AuNPs increased, a proportional increase in both the number and size of deposited AuNPs on Zn(OH)2 NS was observed. To understand how the variation in the number and size of AuNPs affects their catalytic activity, the electrocatalytic activity of different composition ratios of Zn(OH)2-Au NS toward nitrite ions was studied using cyclic voltammetry and amperometric technique. The TPDT-stabilized Zn(OH)2-Au NS showed high electrocatalytic activity, attributed to the effective electron transfer from Zn(OH)2 NS to AuNPs, creating a synergistic effect that enhances the overall activity. The optimal Zn(OH)2-Au NS modified electrode showed an amperometric sensitivity of 5.72 nA/µM and a limit of detection of 1.2 µM for nitrite ions in water sample well below the guideline value of WHO. This demonstrates the practical applicability of this method for real-world water analysis.

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid.

The reaction between 5-acetylbarbituric acid and 4-dimethylthiosemicarbazide or 4-hexamethyleneiminyl thiosemicarbazide produces 5-acetylbarbituric-4-dimethylthiosemicarbazone (H2AcbDM) and 5-acetylbarbituric-4N-hexamethyleneiminyl thiosemicarbazone (H2Acbhexim). Eight new complexes with different copper(II) salts have been prepared and characterized using elemental analysis, molar conductance, UV-Vis, ESI-HRMS, FT-IR, magnetic moment, EPR, and cyclic voltammetry. In addition, three-dimensional molecular structures of [Cu(HAcbDM)(H2O)2](NO3)·H2O (3a), [Cu(HAcbDM)(H2O)2]ClO4 (4), and [Cu(HAcbHexim)Cl] (6) were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out. The H-bonded assemblies were further studied energetically using DFT calculations and MEP surface and QTAIM analyses. In these complexes, the thiosemicarbazone coordinates to the metal ion in an ONS-tridentate manner, in the O-enolate/S-thione form. The electrochemical behavior of the thiosemicarbazones and their copper(II) complexes has been investigated at room temperature using the cyclic voltammetry technique in DMFA. The Cu(II)/Cu(I) redox system was found to be consistent with the quasi-reversible diffusion-controlled process.

Influence of phase transition with annealing temperature on structural, morphological, and supercapacitive characteristics of molybdenum oxide nanostructures

In this study, molybdenum oxide nanostructures (MoO3 NSs) were effectively synthesized through a simple, low-cost, surfactant-free, low-temperature, and scalable chemical co-precipitation method and investigated their synergistic effect with annealing temperature on energy storage applications for the first time. Herein, we have reported a phase transition of MoO3 NSs from hexagonal to orthorhombic after the annealing temperature varied from 100°C to 500°C at constant time. Additionally, the resultant NSs were thoroughly examined for their physio-chemical characteristics, which revealed the stable phase formation of the MoO3 NSs, respectively. Furthermore, the electroactive MoO3 NSs were pasted on Ni-foam substrate (M@NF), and electrochemical properties were evaluated using a three-electrode setup at room-air temperature in 1 M KOH aqueous electrolyte across the potential range of 0 V to 0.786 V. As a result, the M@NF-5 electrode exhibited an impressive specific capacitance of 976.84 F g−1 at a scan rate of 1 mV s−1, a higher energy density of 73.69 Wh kg−1, and a power density of 655 W kg−1 at 5 mA g−1. The non-linear galvanostatic charge-discharge (GCD) profile aligns well with the cyclic voltammetry (CV) analysis. Both CV and GCD techniques confirm the pseudocapacitive behavior, with 83% capacitive retention observed after 2000 cycles. The fabricated symmetric device (M@NF-5//M@NF-5) exhibits enhanced electrochemical performance with a specific capacitance of 67.35 F g−1 at 5 mA g−1 and with an energy density of 18 Wh kg−1, and a power density of 1750 W kg−1 at a specific current. These findings underscore the potential of chemically deposited α-MoO3 as an auspicious material for use in supercapacitor applications.

Environmentally benign synthesis and characterization of Bi2O3‐Sb2O3 nanocomposite: Investigation of its potential as electrode material in energy storage and generation applications

A shift to alternate energy sources is needed at the present time to address rising environmental concerns. The current research work aims to use a chemical‐free and green route to synthesize nanocomposite for their application as an electrode in the generation as well as storage of energy. Subsequently, the green synthesis of Bi2O3‐Sb2O3 nanocomposite was carried out using the leaf extract of Amaranthus viridis. The synthesized nanocomposite revealed a well‐arranged pattern of spherical nanoparticles with a crystal size of 29.43 nm and a band gap value of 2.5 eV. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) potentials of Bi2O3‐Sb2O3 were studied through linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), whereas the energy storage studies were performed using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) techniques. The synthesized nanomaterial showed promising results for HER with an overpotential value of 205 mV as compared with OER, where an overpotential value of 450 mV was observed. However, excellent cyclic stability was witnessed for both reactions up to 1000 cycles. CV studies revealed an outstanding capacitance value of 348 F/g at a scan rate of 2 mV/s, whereas a specific capacitance of 269.5 F/g at a current density of 0.5 A/g was observed using GCD. The 15 h of electrode stability further endorsed the potential of synthesized material for energy‐based applications.

Comprehensive investigation on fabrication, spectral characterization and biological importance of Co(II) and Ni(II) heteroleptic complexes

Using the microwave irradiation approach, novel metallic complexes of Cobalt [Co(II)] and Nickel [Ni(II)] complexes of 2-aminothiazole (ATZ) and thiocyanate ligands [IUPAC Name: Di(2-aminothiazole) thiocyanato cobalt(II), Di(2-aminothiazole) thiocyanato nickel(II)] were created. The molecular formulas and the geometry of the complexes have been deduced by elemental analysis, molar conductance, magnetic moment, UV–visible, FT-IR, thermogravimetric analysis, cyclic voltammetry, and powder-XRD techniques. Molar conductance values indicate that the complexes are non-electrolyte (1:0) type. The complexes have octahedral structure is revealed by the magnetic moment and UV–visible spectra. The FT-IR spectra reveal that the 2-aminothiazole and thiocyanate ions are coordinated to the metal ion in a monodentate manner. The antibacterial capabilities of ligands and their Co(II) and Ni(II) compounds were studied against a restricted set of microorganisms utilizing the agar-well diffusion method and varying concentrations.When compared to free 2-aminothiazole ligand, the complexes exhibit possible activity against the fungus than bacteria. By assessing how well the complexes and ligands interact with the stable free radical DPPH, their ability to scavenge free radicals has been established. Comparing the complexes to the free ligand, the complexes exhibit greater antioxidant activity due to the fact that metal complexes are widely recognized for their capacity to accelerate medication action and boost therapeutic agent potency when they coordinate with a metal ion. The primary goal of this research is to develop multimodal medicinal drugs, which include studying the roles of 2-aminothiazole and its transition metal complexes.

Facile synthesis and electrochemical investigation of graphitic carbon nitride/manganese dioxide incorporated polypyrrole nanocomposite for high-performance energy storage applications

Abstract Manganese dioxide (MnO2) nanoparticles were modified by graphitic carbon nitride (GCN) and polylpyrrole (Ppy) to enhance their electrochemical performance. The surface influence, crystalline structure, and electrochemical performance of the Ppy/GCN/MnO2 material were characterized and compared with those of pristine MnO2. It is found that surface modification can improve the structural stability of MnO2 without decreasing its available specific capacitance. The electrochemical properties of synthesized Ppy/GCN/MnO2 electrode were evaluated using cyclic voltammetry (CV) and AC impedance techniques in 5 M KOH electrolyte. Specific capacitances of 486, 815, 921, and 1377 F/g were obtained for MnO2, Ppy/MnO2, GCN/MnO2, and Ppy/GCN/MnO2, respectively, at 5 A/g. This improvement is attributed to the synergistic effect of GCN and Ppy in the Ppy/GCN/MnO2 electrode material. The Ppy/GCN/MnO2 electrode in KOH has average specific energy and specific power densities of 172 Wh kg−1 and 2065 W kg−1, respectively. Only 2 % of the capacitance’s initial value is lost after 10,000 cycles. The resulting Ppy/GCN/MnO2 nanocomposite had very stable and porous layered structures. This work demonstrates that Ppy/GCN/MnO2 nanomaterials exhibit good structural stability and electrochemical performance and are good materials for supercapacitor applications.

Enhanced pseudocapacitance performance of conductive polymer in the presence of synthesized mesoporous MnO2@Zeolite-Y

In the current study, mesoporous MnO2@Zeolite-Y (MOZ) was synthesized using the ultrasonic method. Then, MOZ was utilized to enhance the electrochemical behavior of poly ortho-aminophenol (POAP) conducting polymer. The POAP/MnO2@Zeolite-Y (MOZ/POAP) composite was synthesized by electropolymerization over the zeolite-modified working electrode surface. To investigate and compare the electrochemical behavior of the synthesized materials, two electrodes of MOZ and MOZ/POAP were designed. Subsequently, the electrochemical characteristics of the two mentioned electroactive compounds were evaluated by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests in a three-electrode setup. The comparison of the results revealed that the MOZ/POAP electrode had a more significant performance and recorded a specific capacitance (Cs) of 422 F g−1 at 1 A g−1 and cyclic stability of 97.2 % over 10,000 cycles. After verifying this electrode's remarkable efficacy, a symmetric supercapacitor of MOZ/POAP was designed and analyzed by CV and GCD techniques in a two-electrode system. This electrode revealed a Cs of 184 F g−1 at 1 A g−1, energy density of 12.02 Wh kg−1, power density of 275 W kg−1, and cyclic stability of 95.7 % over 10,000 cycles. This impressive performance was due to the presence of the manganese metal in MOZ and nitrogen and oxygen species of POAP in improving the pseudocapacitance behavior, POAP as a conductive chemical and mesoporous zeolite-Y for enhancing the electrical double-layer behavior of the electrode by providing a medium for electrochemical reactions.

Design of highly effective organic catalyst for hydrazine electrooxidation: Iodobenzo[b]furan derivatives

In this study, we investigate the electrochemical characteristics of 2-aryl/alkyl-3-iodobenzo[b]furans as anode catalysts for hydrazine (N2H4) fuel cells. Cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the performance of these heteroaromatic compounds. The results demonstrate the promising potential of the 2-aryl/alkyl-3-iodobenzo[b]furans in fuel cell technology. Among the tested organic catalysts (2a, 2b, 2c, 2d, and 2e), 2a exhibited the highest electrocatalytic activity, giving a total current density of 26.62 mA/cm2 within the potential range of −0.4 to −0.8 V. 2-aryl/alkyl-3-iodobenzo[b]furans were synthesized by using palladium/copper-catalyzed Sonogashira cross-coupling reactions, followed by electrophilic cyclization with iodine (I2). All products were characterized using 1H and 13C NMR spectroscopy, confirming their structures and providing insights into their chemical properties.

Electrochemical Properties and Determination of Serotonin with Graphene/Coal Tar Pitch/Pencil Graphite Sensor Electrode using Square Wave Adsorptive Stripping Voltammetry Technique

In the present work, electrochemical and spectroelectrochemical behaviors of Serotonin (5-HT) were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Cyclic voltammetric experiments of 5-HT on graphene/coal tar pitch/pencil graphite electrode (GR/CTP/PGE) were carried out between 0.0 V and 1.8 V potential range at a scan rate of 100 mV s-1 with 20 cycles in non-aqueous media. Surface characterizations were performed using CV, EIS and scanning electron microscope (SEM). Effect of different pH values was investigated by square wave voltammetry (SWV) for determination of 5-HT. Optimization of accumulation time was determined using square wave adsorptive stripping voltammetry (SWAdSV) within potential range of -0.2 to +0.6 V. 5-HT standard solutions changing from 75 µM to 1.0 µM were prepared and the corresponding peak currents were measured. From the obtained data calibration equation was derived Ip = 0.0329C5-HT + 0.1511 with correlation coefficient (R2) 0.9958. LOD was 3.51x10-7 M and LOQ was 1.05x10-6 M.

Investigation of Electrochemical Properties and Behaviors of NBITEP Molecule; Availability of Sensor Electrode in Determination of Hg2+ with SWAdSV Technique

This Master's Thesis focuses on the synthesis and structural elucidation of 4-(2-((6-nitro-1h-benzo[d]imidazol-2-yl)thio)ethyl)phenol (NBITEP) molecule, along with its electrochemical behaviors. Electrochemical studies were carried out employing a glassy carbon (GC) electrode as the working electrode. The cyclic voltammetry (CV) technique was utilized for modification and characterization processes. Furthermore, the potential of the modified surface as a sensor electrode for Hg2+ ion detection was investigated using square wave adsorptive stripping voltammetry (SWAdSV). Detailed examinations were conducted in a phosphate buffer solution (PBS) medium specifically for Hg2+ ion detection, demonstrating the suitability of the reduced NBITEP modified GC electrode surface as a sensor electrode.