Cyclic Voltammetry Research Articles

A novel 2D nickel coordination polymer based on Trimesic acid with glyphosate coordination capabilities

This work presents the synthesis and characterization of a novel coordination polymer entitled Ni-BTC, using nickel as metallic centers and Trimesic Acid (H₃BTC) as linkers. This new structure was characterized using Single Crystal X-ray Diffraction (SCXRD), exhibiting a MOF (metal–organic framework) structure, with a minimal formula of {[Ni(HBTC)(DMF)₂]·xDMF}. The structure exhibits a 2D network expanding in the equatorial direction, where the Ni(II) center is hexacoordinated and N,N'-dimethylformamide (DMF) solvent molecules are coordinated along the axial axis. Additionally, a Co-BTC coordination polymer was synthesized, with an already known structure similar to Ni-BTC, given the coordination modes of the BTC and DMF ligands. The structure of Ni-BTC is also a pseudo-polymorph of the previously published MOF [Ni(HBTC)(DMF)₂·(guest)] (3). The crystallographic data illustrate the structural differences. Ni-BTC was also analyzed by Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (FESEM-EDS), revealing two different phases, one containing chloride anions originating from the precursor salt NiCl₂∙6H₂O. Upon substitution of this precursor with Ni(NO₃)₂∙6H₂O, only one phase was observed, indicating the influence of the counter-ion in modulating new phases during synthesis. Ni-BTC was further characterized by thermal methods such as Thermogravimetric Analysis and Differential Thermal Analysis (TGA and DTA), showing moderate thermal resistance. The Magnetic Susceptibility data indicated a + 2 state for both metal centers. Finally, the bidentate molecule Glyphosate (GLY), widely used as a pesticide and recognized as an environmental pollutant, was employed for coordination with Ni-BTC, as in this structure, the axial DMF ligands are labile and can be replaced by glyphosate molecules. This coordination capability was demonstrated by Powder X-ray Diffraction (PXRD) and Infrared Spectroscopy (FTIR), along with electrochemical techniques such as Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV), thus confirming glyphosate coordination in Ni-BTC, with potential applications in detection and removal systems.Graphical

An electrochemical bio-electronic tongue based on borophene/PPy@ITO hybrid for selective caffeine identification.

Caffeine is a natural stimulant found in various plants. Some individuals are particularly sensitive to caffeine and may experience adverse effects even with minimal intake. In order to address the potential health risks associated with high caffeine use, it is imperative to establish a precise, straightforward, efficient, and cost-efficient approach for measuring caffeine levels in regularly consumed items. This article explores electrochemical techniques for monitoring bitterness induced by caffeine. The fabricated bio-electronic tongue (Bio-ET) comprised a modified electrode made of borophene/PPy@ITO, created by electropolymerizing polypyrrole (PPy) onto indium tin oxide (ITO) and subsequently decorating it with borophene sheets. Cyclic voltammetry (CV) was used to investigate the electrochemical characteristics of caffeine on borophene/PPy@ITO. The findings revealed that the Bio-ET exhibited strong electro-oxidation and reduction activity towards caffeine, indicated by the presence of distinct redox peaks. The Bio-ET demonstrated a linear range from 0.5 to 700 μM with a limit of detection (LOD) of 0.177 μM. The Bio-ET electrode was successfully employed for caffeine quantification in real samples, including coffee, black tea, and regular tea, yielding excellent electrocatalytic performance. Furthermore, the potential of the Bio-ET system could lead to the development of portable, user-friendly devices for on-site analysis, facilitating rapid testing in various settings, such as beverages and pharmaceuticals, and presenting a promising direction for both research and commercial applications.

Photooxidation and Cleavage of Ethynylated 9,10-Dimethoxyanthracenes with Acid-Labile Ether Bonds.

This paper describes a series of 12 9,10-dimethoxyanthracene derivatives functionalized with a range of electronically diverse ethynyl substituents at the 2 and 6 positions, aimed at tuning their optoelectronic properties and reactivity with singlet oxygen (1O2). Optical spectroscopy, cyclic voltammetry, and density functional theory calculations reveal that the ethynyl groups decrease the HOMO-LUMO gaps in these acenes. Notably, bis(dimethylanilineethynyl) substituents increase the wavelength of absorbance onset by over 60 nm compared to 9,10-dimethoxyanthracene (DMA). Furthermore, all 12 molecules react with 1O2 through cycloaddition at the 9 and 10 positions to form endoperoxides. Although the presence of ethynyl groups decreases the reaction rates, they are at least 40% of the rate observed for DMA. Finally, these endoperoxides cleave to form quinones when exposed to protic acid. This behavior, combined with the red-shifting of absorbance spectra, emphasizes their potential in photocleavable materials.

Metal oxides carbon xerogel nanocomposite for methanol oxidation fuel cell

The primary requirement for electrode materials in direct methanol fuel cells (DMFC) is efficient electrocatalyst that exhibit high tolerance to methanol oxidation, excellent stability, and reasonable cost. The combination of distinct active materials with distinctive architectures may facilitate the attainment of this objective. The present study included the preparation of a Carbon Xerogel Doped with various metal oxides derived from Banana peels. The nanocomposites were thoroughly examined utilizing several characterization modalities including XRD, FTIR, and SEM. The electrocatalytic performance of Carbon xerogel doped with Iron (Fe3O4/CX), carbon xerogel doped with magnesium (MgO/CX), and carbon xerogel doped with Copper (CuO/CX) about the Methanol Oxidation Reaction (MOR) was investigated using electrochemical methods such as cyclic voltammetry, impedance spectroscopy, and chronoamperometry. The results showed that the Fe3O4/CX, MgO/CX, and CuO/CX are effective electrocatalysts with an onset potential of around 1.00 V and current densities of approximately 42.98 mA cm − 2, 28.2784 mA.cm − 2, and 6.60698 mA.cm − 2, respectively, in the optimized electrolyte for methanol oxidation. The stability of Fe3O4/CX, MgO/CX, and CuO/CX electrodes was examined using chronoamperometry and the Cyclic Stability method. The results revealed that the (Fe3O4/CX) electrode exhibited outstanding stability throughout the whole 60-minute chronoamperometry Technique and demonstrated great stability for 100 cycles in the Cyclic Stability technique. The remarkable electrochemical activity and stability may be attributed to the synergistic effect of Fe3O4/CX, which provided sufficient active sites for methanol electro-oxidation and reduced the equivalent series resistance, as shown by the electrochemical impedance spectroscopy analysis. This work used environmentally friendly materials, which presents a novel opportunity to enhance the efficiency of methanol oxidation via the utilization of affordable catalysts. This study of the theoretical technique methods for establishing the route of methanol decomposition, and systematizes their confirmation with experimental data, within the methodological framework.

Accurate evaluation of diffusion coefficient for electroactive analytes in human serum samples using nitrogen-terminated sputtered carbon film electrode.

We have developed an N-terminated carbon film electrode that allows accurate determination of the diffusion coefficient of electroactive molecules dissolved in a highly concentrated serum protein solution. The carbon film electrode was formed by the unbalanced magnetron sputtering (UBM) method. Then, nitrogen functional groups were introduced by employing NH3 or H2O plasma treatment. Cyclic voltammetry measurements with ferricyanide ion ([Fe(CN)6]3-) showed that the N-terminated carbon film electrode exhibited great anti-fouling property against simulated serum proteins (50mg/mL human serum albumin and 15mg/mL γ-globulin dissolved in 1M KCl solution). In contrast, glassy carbon, H2O plasma-treated, and especially untreated carbon film electrodes were subject to severe electrode fouling, making it difficult to electrochemically determine the diffusion coefficient of the [Fe(CN)6]3- ion. The control experiment using less adsorptive ethylene glycol as a viscosity modifier showed that the increase in viscosity is a main factor of the decrease in diffusion coefficient for nitrogen plasma treated electrode, which is not significantly affected by the possible interaction between [Fe(CN)6]3- ions and serum proteins. Finally, we applied the electrode for the electrochemical analysis of acetaminophen dissolved in phosphate buffer (0.1M, pH = 7.0), which suggests that NH3 plasma-treated carbon film exhibits the lowest ΔE increase when we compare ΔE with and without proteins and also a more stable peak current in continuous voltametric measurements compared with other carbon electrodes.

Fabrication of CoPcMWCNTs nanocomposite for supercapacitor applications

Abstract The advancement of sophisticated materials for supercapacitors is essential for improving energy storage efficiency, especially in scenarios that demand high power density and extended cycle life. In this study, we synthesized CoPcMWCNTs nanocomposite and investigated its supercapacitive properties. The nanomaterials fabrication was successfully confirmed using EDX, XRD, SEM, FTIR, and UV-visible spectroscopy techniques.
Electrochemical techniques such as galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were employed to determine the power density, specific capacitance, cycling stability, and energy density of the fabricated materials. Benefiting from the synergistic effects of CoPc and fMWCNTs, the hybrid supercapacitor exhibited a lower charge transfer resistance (Rct) of 0.11 kΩ, high specific capacitance of 508.67 F/cm2, lower phase angle of 32°, high power density of 700 mW/cm2, and high energy density of 138.48 mWh/cm2. The findings emphasize the potential of CoPcMWCNTs nanocomposite for high-energy applications and long-term cycling performance, hence contributing to the advancement of next-generation supercapacitors. 

A Cobalt-based Nanostructured Electrode Prepared by a Fast Chemical Method

The demand for nanomaterials is rapidly increasing in most applications, such as energy storage devices. Many nanomaterial synthesis methods are energy-consuming methods requiring high temperatures, prolonged reaction time, complicated steps, or expensive equipment. Herein, nanostructures of cobalt hydroxide chloride, Co2(OH)3Cl, have been directly deposited on carbon cloth microfibers by a fast and simple step of chemical bath deposition. Co2(OH)3Cl nanoparticles appear in only 10 minutes of the deposition time, then the nanoflakes are grown in 60 minutes, as imaged by scanning electron microscope. The crystal structure of Co2(OH)3Cl is characterized using X-ray diffraction, while the results of energy-dispersive X-ray spectroscopy confirm the elemental analysis. The electrochemical energy storage mechanism of Co2(OH)3Cl electrode in potassium hydroxide electrolyte depends on the semi-reversible redox reactions as investigated by the cyclic voltammetry and by the galvanostatic charge-discharge measurements. As a result, the prepared electrode in 60 min exhibits a maximum specific capacitance of 313 F/g versus 293 F/g for the prepared electrode in 10 min, both at 1 A/g. The good electrochemical performance is attributed to several features, including the nanoflakes morphology that enables electrolyte ions to penetrate the electrode freely, the well-crystallized structure, and the solid electronic path between the current collector and the active material indicated by the Nyquist plot of electrochemical impedance spectroscopy. Our cost-effective synthesis of cobalt hydroxide chloride nanostructures on woven substrates offers flexible binder-free electrodes in alkaline electrolytes. This research opens up the potential for these materials to be used as a power source in smart textiles and wearable electronics, thereby contributing to the advancement of these fields.

A comparative study on material removal rate and surface roughness during electrochemical machining of 100Cr6 steel in oxidizing and reducing electrolytic environments

Electrochemical machining is a promising technique for creating microtextured surfaces on engineering materials due to its advantages, including a high material removal rate and superior surface finish. Electrochemical machining, however, faces challenges that hinder its precision, primarily due to the formation of a passive oxide layer on the workpiece surface. This oxide layer negatively affects both material removal rate and surface roughness (Ra), complicating the machining process. High current densities (> 20 A/cm²) can improve material removal rate, but they also increase energy consumption and worsen surface finish quality due to the intensified oxide layer formation. This dynamic creates a trade-off between increased material removal and a deteriorated surface finish. The article investigates ways to overcome these limitations by selecting appropriate electrolytic environments for the process. The study focuses on the anodic dissolution behavior of 100Cr6 steel in two distinct electrolytic solutions. The first is an oxidizing electrolyte, consisting of potassium dichromate (K2Cr2O7) and sodium chloride (NaCl), which promotes oxidation. The second is a reducing electrolyte, containing copper sulfate (CuSO4) and NaCl, which affects the electrochemical dissolution process differently by reducing the steel surface. The maximum improvement in material removal rate with the oxidizing electrolyte is observed at 22%, but simultaneously, a reduction in surface finish quality by 16.4% is noted. The reducing electrolyte offers much better overall performance, with significant improvements in both material removal rate (48.5%) and surface finish quality (21.7%). This is attributed to the reduction in oxide layer formation, which allows for a more controlled and efficient machining process. Analytical techniques like cyclic voltammetry (CV), UV–visible spectrophotometry, and field emission scanning electron microscopy (FESEM) were employed to analyze the dissolution process and visualize surface changes after machining. The results show that the oxidizing environment exposes more metal surfaces than the reducing environment, which aids in understanding and optimizing electrochemical machining processes.

Unifying Electrochemically-Driven Multistep Phase Transformations of Rutile TiO2 to Rocksalt Nanograins for Reversible Li+ and Na+ Storage.

Rutile titanium dioxide (TiO2(R)) lacks octahedral vacancies, which is not suitable for Li+ and Na+ intercalation via reversible two-phase transformations, but it displays promising electrochemical properties. The origins of these electrochemical performances remain largely unclear. Herein, the Li+ and Na+ storage mechanisms of TiO2(R) with grain sizes ranging from 10 to 100 nm are systematically investigated. Through revealing the electrochemically-driven atom rearrangements, nanosize effect and kinetics analysis of TiO2(R) nanograins during repeated cycling with Li+ or Na+, a unified mechanism of electrochemically-driven multistep rutile-to-rocksalt phase transformations is demonstrated. Importantly, the electrochemically in situ formed rocksalt phase has open diffusion channels for rapid Li+ or Na+ (de)intercalation through a solid-solution mechanism, which determines the pseudocapacitive, "mirror-like" cyclic voltammetry curves and excellent rate capabilities. Whereas, the nanosize effect determines the different Li+ and Na+ storage capacities because of their distinct reaction depths. Remarkably, the TiO2(R)-10 nm anode in situ turns into rocksalt nanograins after 30 cycles with Na+, which delivers a reversible capacity of ≈200 mAh g-1, high-rate capability of 97 mAh g-1 at 10 A g-1 and long-term cycling stability over 3000 cycles. The findings provide deep insights into the in situ phase evolutions with boosted electrochemical Li+ or Na+ storage performance.

Chemo-Selective Electrochemical Pinacol Coupling of Aldehydes and Ketones Using TMSN3 as a Promoter.

The pinacol coupling is a significant method for carbon-carbon bond formation. Here, we present an efficient electrochemical approach for pinacol coupling of aldehydes and ketones using TMSN3 as a sacrificial reagent. This method exhibits broad applicability to aryl, heteroaryl, and alkyl aldehydes/ketones with excellent chemo-selectivity and high yields (40 examples, up to 99% yield) under mild conditions. This method can also be applied in the selective reduction of phthalimides to hydroxyl lactams in good yields. The proposed mechanism was elucidated by control experiments and cyclic voltammetry.

Carbonyl-nitrogen multi-resonance emitters for efficient OLEDs with high color purity

Multi-resonance (MR) materials hold an intriguing feature of narrow emission spectra and have attracted considerable attention in the manufacture of high-definition organic light-emitting diodes (OLEDs). However, the majority of MR materials are composed by a boron-nitrogen skeleton, which is unfavorable for expanding the scope of luminescent materials with narrow emission spectra to meet various application demands. In this work, we wish to report a new carbonyl-nitrogen (C = O/N) skeleton of 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione (QA), and three tailored C = O/N MR molecules are synthesized and fully characterized by crystallography, thermal measurement, cyclic voltammetry, steady-state and transient spectroscopy and theoretical calculation. They show efficient green emissions with narrow full width at half maximum (FWHM) of about 27 nm and high photoluminescence quantum yields of up to 93% in doped films. Efficient hyperfluorescence OLEDs are fabricated using these materials as emitters, providing pure green lights with electroluminescence peaks at 526‒538 nm, narrow FWHMs of 29‒33 nm, excellent external quantum efficiencies of up to 29.48% and small efficiency roll-offs. These results reveal that QA could be a potential skeleton for exploring efficient C = O/N MR molecules.

Synthesis and characterization of Co-W alloy coatings for enhanced hydrogen evolution: effects of bath composition and deposition parameters

This study explores the development of Co-W alloy coatings as efficient electrode materials for the hydrogen evolution reaction (HER), offering new insights into their performance. Using a specially formulated electrolyte bath with glycerol as an additive, Co-W alloy coatings were deposited on copper under different [Co2+]/[WO4 2−] molar ratios. Their electrocatalytic efficiency was evaluated in 1 M KOH through cyclic voltammetry (CV), chronopotentiometry (CP), and hydrogen gas measurements using a custom glass device. The results showed that the combination of Co and W in the coatings significantly enhances performance, as confirmed by SEM, XRD, and EDS analyses. Potentiodynamic polarization studies further explained the HER mechanisms. This work introduces a unique bath composition and demonstrates how optimizing the alloy composition can improve HER activity, paving the way for better electrocatalysts. The study identified that the Co-W coating prepared using a 0.35 M solution at a current density of 1 Adm2 demonstrated the highest electrocatalytic efficiency. This performance was attributed to the tungsten content of approximately 30 wt% and the maximum hydrogen evolution observed under these optimized conditions. The hydrogen evolution reaction (HER) in Co-W alloys follows the Volmer-Heyrovsky mechanism, characterized by the rapid evolution of hydrogen.

Low-Temperature Synthesis of NiO Structures: Tailoring Morphology for Enhanced Dielectric Performance

Abstract Abstract:
Nickel oxide (NiO) is a widely studied material for energy storage applications due to its excellent structural and functional properties. This study explores the effect of synthesis pH on the structural, optical, and dielectric properties of NiO nanoparticles to optimize their performance. NiO was synthesized via a hydrothermal method at pH 8 and 12, followed by calcination at 200°C. At pH 12, X-ray diffraction confirmed the phase transition from β-Ni(OH)₂ to NiO, while TEM analysis revealed the formation of a one-dimensional (1D) structure. Optical studies using UV-visible spectroscopy and photoluminescence revealed defect states that contribute to improved energy storage performance. Dielectric studies revealed superior performance at pH 12. Electrochemical cyclic voltammetry confirmed the enhanced stability and energy storage capabilities of NiO with 1D structure. These findings establish NiO synthesized at pH 12 as a promising candidate for advanced energy storage technologies.
Keywords: NiO nanoparticles, hydrothermal synthesis, Optical properties, Dielectric properties, Energy storage.


Dopant Sensitive Electrolytic Etching of Germanium with High Selectivity

Abstract The enhanced charge carrier mobility and photon absorption compared to silicon make germanium attractive for next-generation photo diodes. However, the complex oxidation behavior of germanium challenges dopant-dependent selective etching that is desired for the fabrication of backside imaging architectures. This report demonstrates electrolytic wet etching of p-doped germanium which proceeds up to 17,500x faster than etching of intrinsic germanium. Homoepitaxially grown layers of germanium were electrolytically etched in potassium hydroxide over a range of biases. Intermittent acquisition of cyclic voltammetry spectra during etching has suppressed the formation of electric double layers, maintained appreciable etch rates, and allowed for in operando process control. The observed etch rates scaled with dopant concentration. An effective etch rate of germanium removal of 2.100±0.044 µm/min was accomplished for a boron dopant concentration of 6E18cm-3. For nominally intrinsic germanium, however, an effective etch rate of only 0.00012±0.00011 µm/min was observed. A series of systematic electrolytic etch experiments have revealed the transfer of 4 electrons per germanium atom removed.

Multifunctional Thick Films Obtained by Electrodeposition of 1,8-Dihydroxynaphtalene, an Allomelanin Precursor.

The deposition of conformal films from redox-active biological molecules, such as catechols, catecholamines, and other polyphenols, has demonstrated great versatility in terms of the substrate used. Precursors of allomelanins, mainly found in plants and fungi, have been largely overlooked as precursors for the design of conformal and robust coatings. Moreover, their potential application for the electrodeposition of films on conductive substrates has not yet been investigated. Here, the electrodeposition by cyclic voltammetry and chronoamperometry of 1,8-dihydroxynaphthalene (1,8-DHN), a precursor of allomelanin, onto gold electrodes and onto Co-Cr alloys from aqueous solution-ethanol mixtures yields films with potential sweep rate tunable thickness and swelling. The resulting films are antioxidants, and the reservoir of antioxidant moieties is not limited to their surface but also extends into the bulk of the film. In addition, the films produced after a limited energy supply (in the potential window -1 to +1 V vs Ag/AgCl) are strongly antimicrobial against two strains of Pseudomonas aeruginosa without further post-deposition treatment. In addition, their mechanical properties allow them to be detached from their substrates as free-standing films, opening avenues for diverse applications in biomedicine, energy storage, catalysis, sensing, and optoelectronics.

Simulation of Interface Characteristics and Charge Transfer Dynamics for Layered Electrodes Using Cascade Capacitance in Supercapacitors by COMSOL Software.

In this investigation, the performance disparity between layer-by-layer (LbL) electrodes and uniformly mixed (UM) electrodes in supercapacitors is evaluated using COMSOL Multiphysics software by utilizing a two-dimensional asymmetric structure simulation model where the LbL electrodes consist of ZnMn2O4 and graphene oxide (GO) with varying layering sequences and scales ranging from millimeters to microns. The results revealed that the LbL electrodes significantly augmented the supercapacitor's performance by enhancing charge and mass transport mechanisms. Across both millimeter and micrometer scales, the LbL electrodes surpassed the uniformly mixed electrodes due to their larger surface area and greater ionic accessibility, resulting in more effective charge storage and faster electron transfer. Cyclic voltammetry (CV) illustrated that the peak current density of the LbL electrodes increased with an increase in layers with four-layer micrometer-scale electrodes displaying characteristics closest to those of an ideal supercapacitor, showcasing more consistent and efficient energy storage and release capabilities. The analysis using electrochemical impedance spectroscopy (EIS) revealed that the LbL electrodes exhibited reduced resistance and significant capacitive characteristics about 109 F/m2. The stacked structure not only improved the surface area and conductivity of the electrodes but also accelerated the charge transfer process, minimized interfacial reaction resistance, and facilitated ion diffusion within the electrodes. Through a combination of simulation techniques and theoretical analysis, this study proposed a stacked capacitance (Cs) theory and developed a cross-scale electrochemical interface model by integrating first-principles calculations with multiscale simulations. These findings provide valuable insights for designing and optimizing high-performance materials and devices, offering a new perspective on enhancing the supercapacitor performance through electrode design.

Utilization of a Selective Paper-Based Flexible Electrochemical Sensor for Epinephrine Determination in Artificial Sweat Using Nickel Oxide and Sulfur-Doped Graphene Conductive Ink

Abstract Epinephrine (adrenaline, EP) is a crucial hormone that regulates the body's response to emergencies. During periods of stress or danger, it is responsible for rapidly mobilizing the body by elevating heart rate, blood pressure, and respiratory rate. Consequently, the accurate and rapid measurement of EP is of significant importance. In this study, sulfur-doped graphene (S-Gr) synthesized using Yucel’s method, and nickel oxide (NiO) were utilized as conductive materials to develop conductive inks. Furthermore, a paper-based flexible electrochemical sensor was constructed for EP determination. The optimum conductive ink for sensor fabrication was identified through optimization process. The sensor was characterized using various techniques, including cyclic voltammetry, electrochemical impedance spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy. The sensor demonstrated a detection limit of 33.16 nM, and its cost-effective and user-friendly design renders it an advantageous option for practical applications. The results obtained from the analytical studies indicated that the sensor exhibits high selectivity towards EP and can successfully detect EP in artificial sweat samples. In conclusion, the proposed sensor serves as a model for future flexible and wearable devices.

Oxygen Evolution Enhancement of Nickel (Hydr)Oxide via Iron Coordination Compound in Alkaline Conditions.

This study investigates the complex dynamics of the oxygen-evolution reaction (OER) in systems involving Ni(Fe) (hydr)oxides and the iron coordination compound Fe phthalocyanine-4,4',4″,4‴-tetrasulfonate. It offers a novel perspective on the interaction between nickel hydroxide and the Fe compound during the OER process. The Fe complex facilitates the controlled release of trace Fe ions into the Ni (hydr)oxides as it undergoes degradation or demetalation within the Ni(II)/(III) potential range. Once the electrode surface reaches saturation with Fe, additional contributions from Fe have minimal impact on OER activity, and the turnover frequency rapidly reaches its maximum value (approximately 1 s-1) under cyclic voltammetry. In situ Raman spectroscopy reveals that the interaction between the iron complex and the electrode surface, as well as the amount of complex deposited or adsorbed, depends on the applied potential of the electrode. Changes in the electrode's potential influence how the Fe complex binds to the surface, through mechanisms such as electrostatic attraction, chemical bonding, or other interactions. This underscores the critical role of potential control in optimizing electrode surface modifications and enhancing the efficiency of electrochemical processes involving the iron complex.

Electrochemical Determination of Capsaicin at A Multiwalled Carbon Nanotubes/CuO Nanocomposite Modified Platinum Electrode

Herein, electrochemical detection of capsaicin (CAP) in sauce and rub samples at a Pt electrode modified with copper oxide nanoparticles (CuO NPs) incorporated with functionalized multi-walled carbon nanotubes (fMWCNTs) was reported. The spectroscopic and microscopic characterization of CuO NPs, fMWCNTs and CuO/fMWCNTs nanocomposite with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy and Fourier-transform infrared spectroscopy (FT-IR) spectroscopy confirmed that CuO/fMWCNTs was prepared from the nanomaterials. Electrochemical characterization of the bare Pt, the fMWCNTs-modified Pt, the CuO NP-modified Pt (Pt-CuO) and the CuO/fMWCNTs composite modified Pt (Pt-CuO/fMWCNTs) electrodes revealed that the Pt-CuO/fMWCNTs exhibited the best electron transfer capabilities. The limit of detection (LOD) and the linear range of CAP at Pt-CuO/fMWCNTs were 0.0881 and 0.357–2.73 µM, respectively. The proposed sensor offered outstanding percentage recovery of 106 and 102% when applied to the electroanalysis of CAP in spiked sauce and rub samples, respectively. Pt-CuO/fMWCNTs also retained about 88% of its initial current response when subjected to 25 cyclic voltammetry (CV) scans in the presence of CAP.

New lanthanum (III) complexes containing azaphosphor β-diketon and diimine ligands: Synthesis, crystallography, morphology properties, DNA binding, DNA cleavage, and DFT calculation.

Two octa-coordinated lanthanum (III) complexes of deprotonated azaphosphor β-diketon and diimine ligands, [LnL3Q] (L=[Cl2CHC(O)NP(O)(NC6H12)2], Q=Phen (C1) and Bipy (C2)), were synthesized and characterized by elemental analysis, IR, and NMR spectra. X-ray crystallography revealed a distorted tetragonal antiprism LaO6N2 coordination geometry around the lanthanum atom in both compounds. Nano-sized complexes (Ć1 and Ć2) were synthesized via a sonochemical process and analyzed using SEM and XRPD. TGA-DTA analysis were performed on complexes in both bulk and nano scales. Redox behavior was also examined by cyclic voltammetry. The interaction between the complexes and calf thymus DNA (ct-DNA) was investigated using UV-Vis spectroscopy, fluorescence titration, viscosity measurements, and gel electrophoresis. C2 and Ć2 likely intercalate between DNA base pairs through van der Waals forces and hydrogen bonding, whereas C1 and Ć1 interact with DNA via groove binding. Further, result indicated the apparent association constant (Kapp) in the range of 4.53×104M-1-26.86×104M-1 with the highest value for nanocomplex Ć2. Fluorescence studies revealed dynamic and static quenching for C1, while the other compounds followed a static quenching process. Hirshfeld surface analysis and the NCI method were employed to demonstrate how non-covalent interactions influence the crystal packing through intermolecular interactions.