The electrochemical conversion of carbon dioxide (CO2) represents a promising strategy for reducing greenhouse gas emissions and facilitating sustainable chemical production. Here, we present a rationally engineered copper foam electrode integrated with a multifunctional nanohybrid comprising copper oxide (Cu2O), bismuth sulfide (Bi2S3), and sulfur-doped graphene (SGr-Bi2S3). The Cu/Cu2O-SGr-Bi2S3 composite leverages synergistic electronic and catalytic interfaces, resulting in outstanding electrocatalytic performance for CO2 reduction. Comprehensive physicochemical and electrochemical analyses, including cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy, demonstrate that the hybrid electrodes deliver significantly higher cathodic current densities and exhibit markedly reduced charge transfer resistance under CO2-saturated conditions compared to unmodified copper counterparts. The nanoscale distribution of Bi2S3 effectively increases the density of active catalytic sites, while strong electronic coupling at the heterointerfaces suppresses the competing hydrogen evolution reaction. As a result, the Cu/Cu2O-SGr-Bi2S3 nanohybrids achieve superior activity, enhanced current densities, and excellent operational stability, outperforming conventional copper-based electrodes. These results position the Cu/Cu2O-SGr-Bi2S3 nanohybrids as highly efficient, scalable, and economically viable electrocatalysts for next-generation CO2 reduction technologies.
This study presents an integrated experimental and theoretical investigation into the corrosion inhibition of carbon steel in 1.0 M HCl using Piper nigrum seed extract and its poly(lactic-co-glycolic acid) or PLGA-based nanoformulation. Electrochemical analyses revealed that the nanoencapsulated system markedly suppressed anodic dissolution and cathodic hydrogen evolution, achieving inhibition efficiencies above 90% across a wide concentration range. Surface characterization via SEM, TEM, EDS, and FTIR confirmed the formation of a compact, adherent protective layer, with distinct shifts in C=O, C-O, and aromatic vibrational bands evidencing chemisorption of phytochemicals and polymer-assisted encapsulation. Complementary density functional theory (DFT) calculations and molecular dynamics (MD) simulations demonstrated strong electron donation, favorable adsorption geometry, and stable inhibitor-metal interactions with adsorption energies exceeding-170 kJ/mol. The combined findings establish a robust mechanistic basis for the inhibitor's performance, highlighting the synergistic benefits of phytochemical constituents and nanocarrier encapsulation. The results not only underscore the promise of Piper nigrum as an eco-friendly corrosion inhibitor but also demonstrate how nanoengineering strategies can advance green chemistry approaches to industrial corrosion mitigation.
In redox systems that obey the Nernst equation, where the surface and bulk concentrations remain in equilibrium during the potential sweep, the Randles-Sevcik equation is seen as a standard tool in both fundamental and applied linear scan voltammetry. As the Randles-Sevcik equation is seen as a key theoretical framework for interpreting voltammetric behavior in electrochemically reversible and diffusion-controlled redox systems considered under conditions of linear scan voltammetry, this foundational relationship becomes inapplicable when extended to pulse voltammetric techniques. Pulse voltammetric techniques differ fundamentally from linear scan voltammetric methods in both potential modulation and in current measurement protocols. The form of applied bias in pulse voltammetric techniques leads to conditions in which each applied pulse disrupts the diffusion profile of redox species of interest. Repeated disruption and compression of diffusion profiles in pulse voltammetric techniques introduce significant complexity into the current-potential behavior of redox species, thereby precluding the direct application of the Randles-Sevcik formalism. This study presents some basic theoretical insights into the limitations of applying Randles-Sevcik-type equations to square-wave voltammetry. In addition, a unifying parameter has been identified that governs the peak current response in square-wave voltammetry, which integrates the effects of potential step, frequency, square-wave amplitude, and temperature. At constant magnitude of the diffusion coefficient, this critical parameter is defined as chi = constant . (F/RT).[E-sw/(dE.f)](1/2) and it is seen as a foundation for developing more comprehensive models and analytical expressions describing peak current dependencies under square-wave voltammetric conditions.
this study, a novel voltammetric sensor for the detection of bisphenol A (BPA) was developed using a reduced graphene oxide (rGO) electrode incorporated with a TiO2-NiO-MnO2 nanocomposite (rGO/TNM). The TNM nanocomposite was synthesized via a hydrothermal method, and its integration with rGO improved the sensor's electrochemical performance by enhancing conductivity, surface area, and active sites. Characterization of the TNM nanocomposite using X-ray diffraction (XRD) confirmed the formation of distinct anatase TiO2, gamma-MnO2, and NiO phases, each contributing to the synergistic enhancement of electrocatalytic properties. Fourier-transform infrared (FTIR) spectroscopy indicated the presence of characteristic metal-oxygen bonds, validating the successful formation of the TNM nanocomposite. Scanning electron microscopy (SEM) revealed a highly uniform and porous morphology with well-dispersed nanoparticles, ideal for maximizing electron transfer. Elemental analysis through energy-dispersive X-ray (EDX) spectroscopy further confirmed the purity and composition of the nanocomposite. Under optimal conditions, the linear range of the rGO/TNM electrode by CV measurement was from 0.1 mu g.L-(1 )to 1.0 mu g.L-1, with a sensitivity and limit of detection (LOD) at 0.01094 mu g.L-1. These results make the developed sensor a promising candidate for environmental monitoring of BPA and highlight the potential of nanocomposite-modified electrodes in advancing electrochemical sensor technology.
A novel bifunctional electrocatalyst, bimetallic Ni/Co phosphide-nitride (BMNi/Co-NP), has been developed for efficient water splitting, targeting both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). This electrocatalyst was synthesized via low-temperature phosphidation of a porous Ni-rich cobalt-containing metal-organic framework (MOF). Characterization techniques, including XRD, FTIR, BET, and SEM, confirm the successful synthesis and structural integrity of the catalyst. The proposed electrocatalyst exhibits remarkable electrocatalytic performance with an overpotential of 270 mV for HER and 440 mV for OER at a current density of 10 mA cm-2. The BMNi/Co-NP not only does it exhibits high catalytic activity, but it also demonstrates excellent stability, making it a promising candidate for large-scale clean energy applications. This research highlights the potential of MOF-derived materials in creating cost-effective, efficient electrocatalysts for sustainable hydrogen production.
contamination of drinking water with heavy metals such as copper (Cu2+) and chromium (Cr3+) poses significant health and environmental risks, necessitating the development of sensitive and selective detection methods. In this study, a carbon paste electrode (CPE) modified with 3-pyrazolyl-pyran-2-one, a heterocyclic ligand containing nitrogen and oxygen donor atoms, was developed for the simultaneous electrochemical detection of Cu2+and Cr3+ ions in drinking water. The interaction between the ligand and metal ions was characterized by Fourier-transform infrared (FTIR) spectroscopy, providing valuable insights into the surface modifications and coordination mechanisms. Electrochemical performance was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV), revealing significant improvements in charge transfer efficiency and electrocatalytic response compared to the unmodified electrode. The sensor demonstrated high sensitivity, low detection limits, and excellent selectivity for Cu2+and Cr3+ ions, with recovery rates ranging from 95-106% for Cu2+and 92-105% for Cr3+, confirming its accuracy and potential for practical applications in water quality monitoring. These results highlight that surface modification with 3-pyrazolyl-pyran-2-one substantially enhances interfacial electron transfer, providing a promising and reliable platform for the detection of heavy metal ions in aqueous environments.
this work, we developed a sensitive and selective immunosensor for the rapid and accurate detection of antibodies against the Newcastle disease virus. The sensor was fabricated using a carbon paste electrode modified with a secondary antibody-HRP conjugate immobilized via adsorption. The detection mechanism is based on electrical changes induced by biological interactions. Key physical parameters influencing current density were investigated and optimized. The modified electrode exhibited a good linear response to varying concentrations of Newcastle disease virus antibodies, as evaluated primarily using cyclic voltammetry (CV) and square wave voltammetry (SWV).
manganese oxide (AMO) nanoparticles (Nnp) were synthesized using the co-precipitation method and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), (EDS) to confirm their structural and morphological properties. The synthesized AMO was incorporated with multi-walled carbon nanotubes (MWCNTs) to fabricate a modified glassy carbon electrode (GCE). This AMO-MWCNT Nnp composite electrode demonstrated remarkable efficiency for the simultaneous electrochemical detection of norepinephrine (NEP), uric acid (URA), and L-tyrosine (L-TY). Employing cyclic voltammetry (CV) and differential pulse voltammetry (DPV), the sensor exhibited excellent sensitivity and selectivity. Under optimal conditions, DPV was used for the simultaneous detection of NEP, URA, and L-TY at AMO Nnp-modified surfaces, achieving low detection limits of 4.04 nM for NEP, 3.01 nM for URA, and 10.31 nM for L-tyrosine. The synergistic effect of AMO Nnp and MWCNTs enhanced electron transfer kinetics, ensuring precise multi-analyte quantification. This work highlights the potential of the AMO-MWCNT Nnp modified electrode as a vigorous platform for advanced biomolecular sensing applications and real sample analysis.
novel and eco-friendly approach is introduced for the quantification of nilotinib in biological samples, employing gel-based electromembrane extraction (G-EME) coupled with fluorescence detection. In this method, a deep eutectic solvent (DES) composed of choline chloride and methacrylic acid (ChCl-MAA) was incorporated into agarose membranes (AG@DESChCl-MAA) to enhance extraction performance. The inclusion of DES significantly improved the conductivity, selectivity, and migration efficiency of nilotinib across the membrane. This system offers several advantages, including simplicity of operation, low cost, portability, and the elimination of toxic organic solvents. The developed method demonstrated good precision, with intra-and inter-day relative standard deviations (RSDs) of 6.5% and 8.6%, respectively. A linear calibration curve was obtained in the concentration range of 0.65 to 10.0 mgL-1, with a detection limit (LOD) of 0.20 mgL-1. These results confirm the potential of the AG@DESChCl-MAA-based G-EME system as a sensitive, green, and costeffective alternative for nilotinib analysis in complex matrices.
study presents the development and characterization of a novel mercury-modified carbon paste electrode (Hg-CPE) for the electrochemical enhancement of the Fenton reaction to degrade toxic organic compounds. The modification was achieved through electrodeposition of mercury at a controlled potential of 0.1 V on the carbon paste electrode surface. The resulting Hg-CPE demonstrated superior electrochemical properties compared to the unmodified electrode, including enhanced electron transfer kinetics and improved catalytic activity toward the Fenton reaction. Electrochemical techniques including cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry were employed to characterize the electrode and evaluate its performance in the electro-Fenton process. The Hg-CPE exhibited exceptional stability and reproducibility, with significant catalytic effects on hydrogen peroxide activation, leading to enhanced hydroxyl radical generation. This modification significantly improved the degradation efficiency of model organic pollutants compared to conventional Fenton processes. The findings of this study provide valuable insights into the development of efficient electrochemical platforms for advanced oxidation processes, offering promising applications in wastewater treatment technologies for the removal of recalcitrant organic contaminants.
Electrochemical systems with inverted redox potentials, where the second electron transfer requires less energy than the first one, often challenge conventional interpretations of sequential redox processes in biomolecules and related complexes. These systems commonly produce a single peak under voltammetric conditions, mimicking a concerted two-electron transfer, thereby obscuring the true stepwise nature of the redox transformation. Through theoretical analysis of a two-step electrode process coupled with a regenerative chemical reaction (the so-called EEC ' mechanism), we demonstrate that increasing the rate of the chemical regeneration step significantly alters the voltammetric response. Notably, this enhanced kinetics induces a negative shift in the potential of the second electron transfer process, eventually resolving the two electron transfer events that otherwise appear merged. Square-wave voltammetry simulations of a diffusional EEC ' mechanism reveal that altering the concentration of the regenerative agent "Y" is essential to achieve this resolution under inverted potential conditions. These findings highlight the critical role of chemical kinetics in shaping voltammetric behavior and provide a powerful framework for studying complex redox systems, including biologically relevant cofactors like iron-sulfur clusters, quinones and flavonoids.
study introduces a dual-function platform that integrates photobiomodulation therapy with a highly sensitive MXene/Ni/Sm-LDH-based electrochemical biosensor for the precise evaluation of hemoglobin levels in patients with anemia. The developed biosensor, constructed on a modified glassy carbon electrode, demonstrated outstanding analytical performance with a detection limit of 0.009 nM and a quantification limit of 0.003 nM for hemoglobin using 10 mu L blood samples from four individuals (two males and two females) with anemia. Cyclic voltammetry confirmed a robust linear response (R2 = 0.9961) within a hemoglobin concentration range of 0.01-0.8 nM. Following green laser irradiation at 505 nm for 10 minutes, blood samples exhibited a 13.2% increase in the electrochemical peak current, correlating with improved hemoglobin availability. Rheological assessments revealed a 15% to 20% decrease in blood viscosity, indicating enhanced red blood cell flexibility and flow. Electrochemical impedance spectroscopy showed a reduction in charge transfer resistance from 18 kS2 (unmodified electrode) to 9 kS2 (modified electrode), signifying better conductivity and electron exchange. Stability testing over 60,000 seconds confirmed the biosensor's long-term operational reliability. The observed physiological enhancements are attributed to mitochondrial adenosine triphosphate production and nitric oxide-mediated vasodilation induced by photobiomodulation. This combined diagnostic and therapeutic strategy offers a promising, non-invasive solution for real-time monitoring and management of anemia.
The current study is on the electrochemical investigation of rutin (RTN) by modifying a carbon paste electrode (CPE) using Yttrium oxide nanoparticles (Y2O3 NPs) and polymerization of lycine. The Y2O3 NPs are synthesized by yttrium (III) nitrate and urea at 350 degrees C. The surface morphology of synthesized NPs is confirmed by Field emission scanning electron microscopy (FESEM) and the composition of NPs by energy dispersive X-ray (EDX) analysis. The modified LMYOCPE (lycine-modified yttrium oxide carbon paste electrode) exhibits remarkable electrocatalytic redox activity toward the detection of RTN in the phosphate buffer solution (PB solution) of pH 5.7. Electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) are widely employed for the investigation and evaluation of sensor performance. The fabricated electrode exhibits redox behavior for the large electroactive surface towards electron transfer. The study is novel because it combines NPs with an electrode system to create a highly sensitive, selective, repeatability, reproducibility, and stability towards RTN analysis.
this research, an innovative cost-effective electrocoagulation (EC) reactor cell was designed with optimized effective parameters for effectiveness of EC technique in the removal of cadmium (Cd) from landfill leachate samples. This was achieved by employing cheap aluminum and stainless steel plates as suitable electrodes, and using solar cells for power, which not only made the system more sustainable but also aided in saving operational costs. The study also discovered that the efficiency of Cd removal from a landfill leachate sample was improved by controlling the current density, adjusting the pH of the solution, optimizing the concentration of supporting electrolyte, and optimum fixing the distance between the electrodes. The results suggested that the optimal operating conditions for the removal of Cd from the raw leachate were current density of 6.0 A/m2, duration time of 40 min, concentration of supporting electrolyte of 2000.0 mg/L NaCl, and the initial pH 8.5. The laboratory experiments showed that the treated samples were free of Cd in all trials, with a removal rate of about 99%. This approach provides a scalable, relatively low-cost method for tackling Cd pollution, an issue that is a big deal given Cd's toxicity and the strict regulatory limits on its discharge.
A sensitive and reliable technique for monitoring lead and cadmium using a reduced graphene oxide-modified glassy carbon electrode (rGO/GCE) and a wireless potentiostat has been developed. In this study, rGO was synthesized employing green tea extract as a reducing and stabilizing agent. The initial glassy carbon electrode was electrochemically activated in a 0.5 mol L-1 nitric acid solution and then coated with rGO by the drop-casting method, which increased the effective surface area and enhanced sensitivity. The rGO-modified glassy carbon electrode was employed to quantify Cd(II) and Pb(II) in an acetate buffer at pH 5 using differential pulse voltammetry. Under optimal conditions, the peak currents of Cd(II) and Pb(II) exhibited good linear relationships with their concentrations in the ranges of 2.4 to 12.5 mu mol L-1 for Cd(II) and 1.5 to 6.8 mu mol L-1 for Pb(II), with detection limits of 1.1 mu mol L-1 and 0.88 mu mol L-1, respectively. The rGO/GCE was applied to analyze metal ions in simulated battery samples, demonstrating reliability and accuracy comparable to atomic absorption spectroscopy.
study discusses an electrochemical biosensor developed for detecting dopamine (DA), utilizing a biosurfactant as its transducer element. Biosurfactants are amphiphilic molecules derived from microorganisms such as fungi, bacteria, and yeast, playing a crucial role in this biosensor. Their hydrophilic and hydrophobic moieties enhance analyte sensitivity, making them ideal for this application. In this work, we precisely fabricated a novel electrochemical biosensor for DA detection by modifying a carbon paste electrode with a biosurfactant (BSB/poly AB25/CPE). We examined the electrochemical behavior of DA across potentials ranging from 0.0 V to 0.8 V, anticipating a possible electrochemical redox mechanism. Additionally, the influence of electrolyte pH on redox behavior was investigated, with pH 7.0 identified as the optimal pH. Key kinetic parameters were determined through scan rate experiments, specifically a charge transfer coefficient of 0.386 and a heterogeneous rate constant of 4.92x10-5 s-1. The biosensor also demonstrated favorable analytical parameters, including a limit of detection (LOD) of 3.2x10-7 M and a limit of quantification (LOQ) of 1.06x10-6 M. The biosensor exhibited excellent repeatability, reproducibility, and stability, confirming its practical utility. Finally, the developed biosensor was successfully applied to quantify DA concentration in pharmaceutical formulations, validating its potential for real-world applications.
In this study, a sensitive electrochemical sensor was developed for the trace determination of thiopental using a sol-gel molecularly imprinted polymer on a pencil graphite electrode modified with functionalized carbon nanotubes. The carbon nanotubes were pretreated using a mixture of nitric and sulfuric acids to enhance surface reactivity. Electrochemical characterization was performed using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The sensor's performance was evaluated based on the oxidation and reduction currents of a redox probe, demonstrating superior recognition ability of the imprinted sol-gel electrode compared to its non-imprinted counterpart. Several experimental parameters, including pH and target molecule concentration, were optimized to achieve maximum response. Under optimal conditions, the sensor exhibited a linear response to thiopental in the concentration range of 0.05-75 mu M, with a detection limit as low as 10 nM. The applicability of the sensor was successfully demonstrated through the analysis of thiopental in real biological samples.
remains the predominant catalyst for the oxygen reduction reaction (ORR) occurring at both the cathode and anode in fuel cells and metal-air batteries; however, its elevated expense, shortage, and restricted consistency in alkaline environments hinder widespread commercialization. To overcome these constraints, this research emphasizes the creation and assessment of a novel multimetallic electrocatalyst obtained from metal-organic frameworks (MOFs) and stabilized with a silicate coating. A hollow-structured catalyst was prepared by carbonizing ZIF-8@Gd-ZIF-67@SiO2, with mesoporous silica (mSiO2) applied to prevent particle aggregation during high-temperature pyrolysis. The integration of carbon frameworks, metal doping, and silica protection effectively enhanced the structural integrity and catalytic performance. Detailed physical and electrochemical studies showed that the newly developed electrocatalysts had a consistent shape, nanoscale particle sizes, and high surface areas. Compared to commercial Pt/C (20%), the Gd-Co-N-PC electrocatalyst achieved an onset potential of-0.12 V and an electron transfer count of 3.69, suggesting a near-four-electron ORR pathway and superior catalytic activity. Stability tests further confirmed its excellent durability under operational conditions. Overall, the developed electrocatalysts offer a promising, cost-effective alternative to platinum-based materials for fuel cell applications, combining high ORR efficiency with robust structural stability for future energy conversion technologies.
This study investigates the electrochemical behavior of glucose in a neutral medium (1 M NaCl) using modified carbon paste electrodes (CPE) containing different percentages of titanium dioxide (TiO2). The influence of metal ion additives (1% Mg2+and 1% Cr2+) on the redox behavior of glucose was also examined to explore potential formulations for novel table sugar products. Electrochemical techniques, including cyclic voltammetry (CV), polarization curves, and electrochemical impedance spectroscopy (EIS) were employed. Results show that the incorporation of TiO2 into the carbon paste electrodes significantly enhances the electrochemical response toward glucose oxidation, with the CPE 50% TiO2/50% carbon paste composition showing optimal performance. The addition of Mg2+and Cr2+ ions further modified the electrochemical behavior, with Cr2+ demonstrating the most substantial enhancement in current density and reduced charge transfer resistance. These findings provide valuable insights for developing modified electrodes for glucose sensing and suggest potential pathways for creating enhanced table sugar formulations with improved electrochemical properties.
This work focuses on the study of the biocatalyzed electrolytic oxidation of methanol by bacteria in a 1M Na2SO4 solution, using a carbon paste electrode modified with poly(1,4-myrcene-co-styrene) polymer. The electrode was obtained by immersing the carbon paste electrode in the polymer for 3 hours, ensuring that the surface of the CPE was uniformly covered with a polymer film. The prepared electrode demonstrated high activity in methanol oxidation. We investigated the impact of various parameters such as scan rate, cycles, and the duration of electrode contact with bacteria. Analysis of the electrode morphology through optical microscopy revealed that the polymer was uniformly deposited on the surface. Subsequently, we studied the electrode behavior using voltammetry techniques, employing the Volta Lab PGZ100 potentiostat. The results of these techniques highlighted the existence of a catalytic effect, leading to improved performance in the methanol oxidation process by bacteria.
