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The design of electrochemical sensors is crucial considering important factors such as efficiency, low cost, biocompatibility, and availability. Manganese oxides are readily available, low-cost, and biocompatible materials, but their low conductivity limits their efficiency as sensors. Today, morphology engineering of manganese oxide has been one of the most common research topics, because manganese oxides' electrochemical properties are highly dependent on their morphologies. In this study, a method for reducing the charge transfer resistance (Rct) of MnO2-based electrodes was established by the cyclic voltammetry technique accompanied by step-by-step heat treatment to electrodeposition MnO2 nanofilm, which remarkably improved the Rct. Next, the sensing performance of MnO2/FTO for two separate measurements was examined, one for the simultaneous measurement of paracetamol (PAR) and 4-aminophenol (4-APh), and the other for the measurement of 4-nitrophenol (4-NP). Under the optimum conditions, the linear ranges of 4-APh, PAR, and 4-NP, were 0.8 to 22.0 µM, 2.0 to 55.0 µM, and 0.1–250 µM, with limits of detection (LOD) of 0.19 µM, 0.60 µM, and 0.01 µM, respectively. It also was unaffected by a 200-fold excess of interferences. In addition, the designed sensor was successfully applied to the analysis of real samples. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor for the highly sensitive and selective determination of dopamine was developed, based on the use of a glassy carbon electrode modified with cobalt(II) polymer. Both electrochemical and morphological characterizations were investigated. Square wave voltammetry (SWV) was used for the determination of dopamine. From the SWV results obtained on the modified electrode under the optimized conditions, the successive addition of dopamine increased the anodic peak current. The results obtained show a linear response of the electrode modified with Co(II) polymer in a wide concentration range. Each concentration decade is characterized by a new calibration plot with a corresponding mathematical expression. The highest sensitivity (13.182) was obtained for the lowest concentration range, and the detection limit of 0.03 µM, calculated based on the 3 × sb/m criterion, indicates a very high sensitivity and great application potential. When analyzing a real sample, the modified electrode showed good electroanalytical activities in terms of oxidation of dopamine, good anti-interference ability, stability, reproducibility, and potential applicability in commercial pharmaceutical samples. [ABSTRACT FROM AUTHOR]

We report the comparison of multiple acetylene black (AB) rigid carbon composites for electrochemical purposes exploring several binders, including one (polyurethane) from a renewable source of castor oil. The acetylene black–based composites presented less roughness and increased surface homogeneity evinced by AFM and SEM images within the micrometer range. Contact angle analysis and Raman spectra confirmed a high degree of surface functionalization associated with structural defects on AB even when the base conductive material is associated with a non-conductive binder. The acetylene black-castor oil electrode presented superior performance (lower resistance to charge transfer and increased peak currents) when compared to its graphite counterparts regardless of the mechanical activation. The proposed electrode presented an excellent electrochemical performance in analyzing contaminants of emerging concern when compared to glassy carbon electrodes. The sustainable aspect of this work is evinced considering the room temperature synthesis, low cost of the AB, and renewable castor oil binder source. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy (EIS) was employed in an attempt to gain insight into the mechanisms of ethyl 2-cyanoacrylate (ECA) curing (polymerisation) and bonding on aluminium alloy 2024 metal. EIS can detect ionic movement, adsorption processes, charge transfer and storage occurring at an adhesive/substrate interface and/or in a bulk bond line during curing. Low-frequency capacitance measurements demonstrated sensitivity to surface polymerisation reactions and were modelled using an equivalent circuit model with two time constants in series. At a frequency of 1 kHz, changes in the dielectric polymer could be readily followed with time, confirmed by employing a crown ether to accelerate the polymerisation process. Hydrolytic degradation of poly-ECA bonds at a stainless steel interface was also investigated. An equivalent circuit model containing a number of circuit components comprising pore, charge transfer and diffusional impedances, along with polymer film, double layer and diffusional capacitances (represented by constant phase elements), was developed. Three regions were identified in the frequency domain and ascribed to processes taking place at the polymer/electrolyte and polymer/metal oxide interfaces. In short, EIS can be employed to follow the rate of polymerisation of ethyl-2-cyanoacrylate and also the degradation of the resulting polymer in saline solution. [ABSTRACT FROM AUTHOR]

A novel electrochemical molecularly imprinted composite (MIC)-based sensor for detection of triclosan was developed. MIC was synthesized from o-phenylenediamine (o–PD), -COOH functionalized multiwalled carbon nanotube (cf-MWCNT), and triclosan by cyclic voltammetry on molybdenum nanoparticle (Mo-NP) embedded cf-MWCNT (Mo-cf-MWCNT) coated glassy carbon (GC) electrode, following removal of surface triclosan to form MIC/Mo-cf-MWCNT/GC. In our earlier work, two novel electrodes MIC/cf-MWCNT/GC and MIC/GC were fabricated. The presence of cf-MWCNT coating substrate on GC in MIC/cf-MWCNT/GC had improved the sensing performance than MIC/GC since presence of this substrate had decreased the electrochemical band gap (Eg) and increased Debye length (λd), Gibb's free energy of adsorption (− ΔGads), electrochemical surface area (Ae), and surface redox site concentration (C*). Therefore, further improvement in sensing performance can be carried out by utilizing Mo-NP in the cf-MWCNT coating substrate using MIC to be the sensing material. This novel electrode (MIC/Mo-cf-MWCNT/GC) provided a limit of detection (LOD) of 900 ppt of triclosan, which was lower than the LOD achieved by using MIC/cf-MWCNT/GC (10 ppb) and MIC/GC (40 ppb). Adsorption isotherm was constructed for MIC/Mo-cf-MWCNT/GC delivering − ΔGads value of 59.049 kJ/mol indicating stronger chemisorption. To understand the role of Mo-cf-MWCNT in detection of triclosan, cyclic voltammetry, electrochemical impedance spectroscopy, and electrochemical band gap studies were conducted. This MIC/Mo-cf-MWCNT/GC showed good selectivity towards triclosan in presence of interfering ions. [ABSTRACT FROM AUTHOR]

Mini passive direct methanol fuel cells (mpDMFCs) appear to be a promising alternative for powering portable devices, since they use a liquid fuel, have a fast refuelling time, have a high efficiency and have a low environmental impact. However, some issues need to be solved before their commercialization, such as methanol crossover, short lifetime and high costs. The present work studies the effect of reducing the anode and cathode catalyst loading on the performance of a mpDMFC towards a reduction in the system costs and the characterization of the system losses. The undesirable losses that affect the fuel cell performance were identified and quantified using the electrochemical impedance spectroscopy (EIS) technique. Accordingly, a novel equivalent electric circuit (EEC) was proposed, accurately reproducing the mini pDMFC. In this work, a maximum power density of 7.07 mW cm−2 was obtained, with a methanol concentration of 5 M, using 2 mg cm−2 Pt-RuB and 4 mg cm−2 PtB. The mpDMFC allowed the cell to work with high methanol concentrations and reduced anode catalyst loadings. [ABSTRACT FROM AUTHOR]

The perovskite structure and electrochemical activity of (La0.80Sr0.20)0.95MnO3−x–(Y2O3)0.08(ZrO2)0.92 (LSM–YSZ) composite cathode can be significantly affected by volatile boron species originated from sealing glass–ceramics. Herein, we investigate the impact of doping the varying Er2O3 content (ranging from 0 to 4%) into an aluminoborosilicate glass to mitigate boron volatilization, its interaction with the LSM–YSZ cathode and consequent effects on its electrochemical performance. The results reveal that the volatility of boron species can be significantly suppressed by introducing Er oxide into the glass network by enhancing the conversion of [BO3] to [BO4] units, thereby increasing the binding energy of boron and strengthening of the glass structure. Moreover, the electrocatalytic performance for the O2 reduction reaction on the LSM–YSZ/8YSZ/LSM–YSZ symmetric cells is studied under open‐circuit conditions in the presence and absence of glass sealants. The analyses utilizing electrochemical impedance spectroscopy (EIS) and distribution of the relaxation times (DRT) analysis indicate that the electrocatalytic performance of LSM–YSZ cathodes can be enhanced in the presence of glass with 4% Er2O3 (GE4). This enhancement in the electrocatalytic activity of the LSM–YSZ electrode for the oxygen reduction reaction (ORR) is attributed to formation of the thin layer on the electrode surface, leading to a notable reduction in the polarization resistance (Rp) from 0.81 Ω cm2 in the glass absence to 0.45 Ω cm2 in the presence of GE4. However, DRT analysis demonstrates that the prolonged exposure of the cathode to GE4 causes a deterioration in cell performance primarily due to the blocking the cathode active sites, which impedes dominant cathode processes of oxygen dissociative adsorption/desorption and charge transfer and consequently reducing kinetics of the ORR. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy is used to study the effect of potential (E) on capacitance (C) of porous tantalum coated with a layer of amorphous Ta2O5. It is shown that there is a positive linear dependence 1/C2 in a wide range of potentials, and its slope can be used to control an oxide layer in porous tantalum. It is established that the transformation of the oxide layer during annealing in the temperature range 100–700°C strongly affects 1/C2(E)-graphics. Annealing at temperatures of 100–500°C raises the concentration of oxygen vacancies in the oxide layer due to partial transfer of oxygen into tantalum, resulting in lower slope of the 1/C2(E) plots as compared with initial non-annealed sample. After annealing at temperatures of 600 and 700°C, a TaO phase forms in the oxide film, accompanied by a strong increase in capacitance and a weak dependence on potential due to the emergence of a high concentration of donors in the oxide film. The promise is shown of using 1/C2(E) dependences to control a layer of oxide in porous tantalum, which could be useful in tantalum capacitor technology. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy (EIS), characterized by its non‐destructive and in situ nature, plays a crucial role in comprehending the thermodynamic and kinetic processes occurring within Li‐ion batteries. However, there is a lack of consistent and coherent physical interpretations for the EIS of porous electrodes. Therefore, it is imperative to conduct thorough investigations into the underlying physical mechanisms of EIS. Herein, by employing reference electrode in batteries, we revisit the associated physical interpretation of EIS at different frequencies. Combining different battery configurations, temperature‐dependent experiments, and elaborated distribution of relaxation time analysis, we find that the ion transport in porous electrode channels and pseudo‐capacitance behavior dominate the high‐frequency and mid‐frequency impedance arcs, respectively. This work offers a perspective for the physical interpretation of EIS and also sheds light on the understanding of EIS characteristics in other advanced energy storage systems. [ABSTRACT FROM AUTHOR]

The goal of this study was to design and construct a biosensor for detecting domoic acid (DA) using bioimmobilization of DA antibodies on the surface of screen‐printed carbon electrodes (SPCEs) enhanced with gold nanoparticles (AuNPs). To accomplish this aim, the SPCE surface was modified by applying AuNPs using electrodeposition, and the optimum modification time was determined by using cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) was performed to thoroughly analyze the electrochemical alterations in SPCEs prior to and during the modification with AuNPs. In addition, we conducted a comprehensive analysis of the structural surface characteristics, topography, and contact angle measurements. The limit of detection (LOD) for the AuNPs‐modified SPCE was determined to be 1.069 ng/mL, whereas the limit of quantification (LOQ) for DA was found to be 3.52 ng/mL using the EIS technique. While many studies concentrate on identifying target molecules through nanoparticle modification, our research surpasses this by offering a comprehensive electrochemical analysis of the modification of AuNPs and a thorough assessment of the changes in the microstructure of the electrode surface. This strategy greatly enhances the progress of biosensor development in the area. In addition, we investigated the harmful effects of DA on human endothelial cells EA.hy926 by subjecting them to different concentrations ranging from 0.001 to 1 ng/mL for a duration of 24 h. This experiment demonstrated that there was a decrease in cell viability that was directly proportional to the concentration of DA. [ABSTRACT FROM AUTHOR]

The transport properties of the perovskites BaPb1 − xSnxO3 (0 ≤ x ≤ 0.4, and x = 1), synthesized for the first time, are investigated in the range (300 –4.2 K). They were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and FTIR-ATR spectroscopy. The weak thermal dependence of conductivity on temperature is characteristic of degenerate behavior with a finite density of states at the Fermi level. The linear behavior indicates a thermally activated mobility (= 4.8 × 10− 6 cm2 V− 1 s− 1) while the negative sign of the thermo-power, indicates that the mobile carriers are electrons, due to non-stoichiometry of oxygen. The band overlapping O2−: 2p-Pb: 6s is involved in the semi-metal BaPbO3. The magnetic susceptibility exhibits a Pauli-type paramagnetism due to itinerant electrons. A pronounced dip, associated with a phonon drag contribution is observed near 25 K. The non-linear dependence of log σ vs. T− 1 at low temperatures results from a variable range hopping evidenced by the plot log σ vs. T− 0.25. The metal-non-metal transition is of Anderson type due to random potential introduced by substituting Pb4+ with Sn4+. The capacitance− 2 potential (C− 2 - E) plots show linear behaviors from which flat band potentials are determined (-0.22 - -0.83 VSCE). The Electrochemical Impedance Spectroscopy exhibits semicircles assigned to the capacitive behavior with a low density of surface states within the gap region. [ABSTRACT FROM AUTHOR]

An aptamer-based electrochemical sensor for the sensitive detection of staphylococcal enterotoxin type A (SEA) is presented. The truncated aptamer AptSEA1.4 used in this work was screened using computational techniques, which reduced the cost of the SELEX screening process. The aptamer-SEA interactions were confirmed by employing circular dichroism (CD) and fluorescence spectroscopy. Afterwards, for developing an electrochemical aptasensor, a fabricated GNR/FTO aptasensor was prepared and characterized using scanning electron microscopy-energy-dispersive X-ray analysis (SEM–EDX), atomic force microscopy (AFM), cyclic voltammetry (CV), and square wave voltammetry (SWV). A detailed investigation of aptamer and SEA interaction in the presence of various experimental conditions was also conducted through SWV and electrochemical impedance spectroscopy (EIS). The aptamer exhibits a strong affinity for SEA, with a dissociation constant (Kd) of 19.93 nM. The aptasensor is sensitive, with a lower limit of detection of 12.44 pg mL−1. It has good stability, repeatability, and specificity and has displayed highly specific and sensitive detection SEA in spiked packaged mixed fruit juice and milk, with a recovery of 95–110%. The aptasensor has high promise for detecting SEA in other food items. [ABSTRACT FROM AUTHOR]

A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified with gold particles (AuPs@PE) and then conjugated with anti-CD9 (Anti-CD9/AuPs@PE) for the detection of exosomes. Variables involved in the biosensor design were optimized with the univariate mode. The developed method presents the limit of detection of 8.7 × 102 exosomes mL−1, which is lower than that of many other available methods under the best conditions. The biosensor was also tested with urine samples from cancer patients with high recoveries. Due to this a unique, low-cost, biodegradable technology is presented that can directly measure exosomes without labeling them for early cancer or metastasis detection. [ABSTRACT FROM AUTHOR]

Enhancing the corona resistance of epoxy resin (EP) is crucial for ensuring the reliable operation of electrical equipment and power systems, and the incorporation of inorganic nanofillers into epoxy resin has shown significant potential in achieving this. In this study, functionalized graphene oxide (KHGO) was synthesized via a sol-gel method to enhance the corona resistance of EP with electrochemical impedance spectroscopy (EIS) used to assess the properties of KHGO/EP composites. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) verified the successful grafting of epoxy groups onto the GO surface. The thermal conductivity and stability of the KHGO/EP composite initially increased with KHGO content but declined when the content exceeded 1.2 wt.%. Positron annihilation lifetime spectroscopy (PALS) indicated that KHGO improved interfacial compatibility with EP compared to GO, with agglomeration occurring when KHGO content exceeded a threshold value (1.2 wt.%). EIS analysis revealed that the corona resistance of the KHGO/EP composite was optimal at a filler content of 0.9 wt.%. After corona treatment, the saturation water uptake of the 0.9 wt.% KHGO/EP composite decreased by 15% compared to pure EP with its porosity reduced to just 1/40th of that of pure EP. This study underscores that well-dispersed KHGO/EP composite exhibits excellent corona resistance property suggesting the potential for industrial applications in high-voltage equipment insulation. [ABSTRACT FROM AUTHOR]

Electrode materials for application in lithium‐ion batteries are commonly probed by X‐ray diffraction (XRD) to investigate their crystalline structure. Grazing incidence wide‐angle X‐ray scattering (GIWAXS) is an extension to XRD since in‐plane structures are also accessible. Additionally, with grazing incidence small‐angle X‐ray scattering (GISAXS), morphological information on the nanoscale can be revealed. In this work, the nanostructure of battery electrodes, which consist of lithium iron phosphate (LiFePO4) as active material, carbon black (CB) as conducting agent, and the polymeric binders polyvinylidenefluoride (PVDF) and poly((trifluoromethane) sulfonimide lithium styrene) (PSTFSILi) is studied by performing GISAXS and GIWAXS. The chemical nature of the binder is tuned by blending PVDF and PSTFSILi. Specifically, a series of LiFePO4 electrodes with polymer blends of the common, non‐conducting PVDF and the single‐ion conducting PSTFSILi with different weight ratios as binders is investigated to understand the influence of the binder on the structure of the electrode in detail. Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) complement these studies to correlate the morphology and structure with the electrochemical behavior. It is found that LiFePO4 crystallites do not exhibit any preferred orientation with respect to the substrate, irrespective of the binder composition, but their size depends on the binder composition. [ABSTRACT FROM AUTHOR]

The present research explores the electrochemical corrosion characteristics of Mg–Zn–Gd (rare earth—RE) alloy and Mg–Zn–Gd–ZnO nanocomposites. A unique stir-ultrasonication followed by squeeze casting technique was used to develop the alloy and nanocomposites. T5 heat-treated Mg alloys and Mg nanocomposite samples were subjected to an electrochemical corrosion test in a solution of 3.5 wt.% NaCl-concentrated demineralized water. The addition of Gd alloying element and ZnO nanoreinforcements combined with squeeze casting led to the finer grains in the Mg nanocomposites. Scanning electron microscopy (SEM) images validate the homogeneous dispersion of nano-ZnO in the Mg matrix. The MgZn precipitates were observed in X-ray diffraction analysis (XRD) peaks and Transmission electron microscopy (TEM) analysis. The hardness results revealed a 34% enhancement in the microhardness of the nanocomposite with 0.2% Gd and 2% ZnO as compared to the base alloy. Electrochemical impedance spectroscopy analysis was performed on the fabricated samples to identify the instantaneous corrosion effect. The reduction in the removal of metal ions was observed during the electrochemical test with a voltage range of − 0.5 to 0.5 V and a 1.92E−05 A/cm2 current density at 1800 s. The enhanced corrosion resistance observed in nanocomposites could be attributed to the presence of a finer grain arrangement, good interfacial strength, and the formation of passivation layers and precipitates in the nanocomposite samples. [ABSTRACT FROM AUTHOR]

The improvement of the water oxidation capability of bismuth molybdate (BM) with selective metal addition under illumination was examined. BM and its Zn-modified (different atomic %) photoanodes were developed over conducting glass substrate through the cost-effective drop-cast method. The maximum photocurrent of ~ 240 µA/cm2 at an applied potential of 1.3 V vs Ag/AgCl was recorded for the 2% Zn modified sample in 0.1 M Na2SO4 solution (PBS, pH 7) under 100 mW/cm2 illuminations. Surface characterizations like scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, and optical analysis such as UV–vis absorbance, photoluminescence, FT-IR, and Raman spectroscopic analyses were performed to determine the physicochemical properties of the semiconductor. The pure bismuth molybdate shows an optical band gap of ~ 2.78 eV, which decreases for the Zn-modified sample, and a minimum of 2.55 eV is detected for the optimized sample. The XRD analysis also reveals that Zn addition into the bismuth molybdate matrix decreases crystallite size with variation in proportions of the constituent metal oxides. The stability of the semiconductors regarding the PEC water oxidation reaction indicates promising results even under continuous illumination for 1 h. The Mott-Schottky study reveals the n-type nature of the semiconductors, whereas the Nyquist analysis indicates minimum charge transfer resistance for the 2% Zn-BMO sample. The PEC action spectra for the optimized photoanode indicate a maximum of 34% incident photon to current conversion efficiency with corresponding 38% absorbed photon to current conversion efficiency, which is more than three times than that of the pure bismuth molybdate. [ABSTRACT FROM AUTHOR]

In this study, a novel triazole compound named 2-(4-((2-methoxy-4-vinylphenoxy)-methyl)-1H-1,2,3-triazol-1-yl)ethan-1-ol (MTE) was synthesized from eugenol, extracted from cloves (Syzygium aromaticum). Eugenol is a natural phenolic compound renowned for its cost-effective and eco-friendly attributes, rendering it a preferred option for industrial uses. The newly prepared triazole was characterized by FTIR and 1H NMR techniques. For the first time, the inhibitory potential of MTE against copper corrosion in a 3.5 wt.% NaCl solution was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) methods. At 1 mM, MTE demonstrated an exceptional ability to inhibit corrosion, achieving an efficacy rate of 94.03%, and exhibited mixed-type inhibitor characteristics. The EIS study showed that the MTE compound formed a thin protective film on the copper surface. X-ray energy dispersive spectroscopy (EDX) coupled with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR-ATR) were used to characterize the protective film formed by MTE on the copper surface. The analyses confirmed the presence of MTE on the copper surface. Furthermore, our results suggest that the adsorption of MTE on the copper surface follows a Langmuir isotherm model. In addition, the negative adsorption-free energy ( Δ G ∘ ads = - 37.19 kJ / mol ) indicates a spontaneous adsorption process. In the field of copper corrosion inhibition in 3.5 wt.% NaCl solutions, theoretical calculations hold great promise. Density functional theory (DFT) and molecular dynamics (MD) simulations are particularly powerful tools. These simulations provide a window into the interactions between MTE molecules and the copper surface at the atomic level. This helps elucidate the mechanisms by which MTE prevents the adsorption of corrosive chloride ions, ultimately protecting the copper from degradation. [ABSTRACT FROM AUTHOR]

This study focuses on the analysis of the different polarization losses in proton exchange membrane fuel cells (PEMFCs) during idling by using the distribution of relaxation times (DRT) method quantitatively. By varying operating parameters, cathodic mass transfer and oxygen reduction reactions were identified as the primary contributors to cathode mass transfer process (P1 peaks) and charge transfer process (P2 peaks) respectively. The resistance values for each polarization were obtained by fitting areas of the DRT peaks and compared with I–V steady-state values to validate the accuracy of the method. The effect of idling conditions on PEMFC attenuation at different current densities was analyzed. The result shows that during idle aging, cathode catalytic layer activation resistance growth accounts for 55% at 0.4 A cm−2, cathode mass transfer resistance for 31.2%, and Ohmic resistance for 13.7%.The electrochemically active area decreased by 16.7% from 27.32 to 22.77 m2 g−1. DRT can quickly and accurately identify the main reason for PEMFC deterioration. [ABSTRACT FROM AUTHOR]

Ductile iron is distinguished by its balance of mechanical properties and other advantageous characteristics, including its capacity to absorb energy. This makes it suitable for applications requiring high strength. However, its performance is impaired by its low corrosion resistance. In this study, a Ni-P coating was applied to the surface of ductile cast iron using electroless nickel plating to increase its corrosion resistance in 0.1 M NaCl. The characterization of the substrate and the coated materials was conducted using scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, and electrochemical noise. The results show that the coating deposited on a ductile iron is amorphous, compact, homogeneous, and well-adhered. The surface hardness is increased by 53%. Also, a notable increase in corrosion resistance is evidenced by the blocking effect of the coating that delimits the access of the electrolyte to the ductile iron coating. The corrosion mechanism is related to the mixed and localized corrosion phenomena for the different evaluation times. [ABSTRACT FROM AUTHOR]

Electrochemical DNA sensors for DNA damage detection based on electroactive polymer poly(proflavine) (PPFL) that was synthesized at screen-printed carbon electrodes (SPCEs) from phosphate buffer (PB) and two natural deep eutectic solvents (NADESs) consisting of citric or malonic acids, D-glucose, and a certain amount of water (NADES1 and NADES2) were developed. Poly(proflavine) coatings obtained from the presented media (PPFLPB, PPFLNADES1, and PPFLNADES2) were electrochemically polymerized via the multiple cycling of the potential or potentiostatic accumulation and used for the discrimination of thermal and oxidative DNA damage. The electrochemical characteristics of the poly(proflavine) coatings and their morphology were assessed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The working conditions for calf thymus DNA implementation and DNA damage detection were estimated for all types of poly(proflavine) coatings. The voltammetric approach made it possible to distinguish native and chemically oxidized DNA while the impedimetric approach allowed for the successful recognition of native, thermally denatured, and chemically oxidized DNA through changes in the charge transfer resistance. The influence of different concentrations of conventional antioxidants and pharmaceutical preparations on oxidative DNA damage was characterized. [ABSTRACT FROM AUTHOR]

The impedance of the paint film varied depending on the environmental test. It is considered that the impedance spectrum of the coating films changed by the effects of water content in the paint film, polymer structure, and elements that penetrated the paint film. However, no clear relationship could be found between the impedance spectrum of the coating film and its internal structure. To understand the change in the impedance spectrum, we performed D-SIMS and AFM-IR analyses on the paint films after the environmental test. The results suggest that the admittance spectra may reflect the state of infiltrated moisture and elements into the coating films. [ABSTRACT FROM AUTHOR]

The corrosion inhibition effects of Drimia maritima (L.) Stearn sin. Urginea maritima (L.) Backer on three different materials, i.e., as-cast Al-7 wt.% Si alloy, SAE 1020 low carbon steel, and commercially pure Al samples, into a stagnant and naturally aerated 0.5 M NaCl solution are evaluated. For this purpose, both the potentiodynamic polarization curves and electrochemical impedance spectroscopy with an equivalent circuit are utilized. It is found that inhibition effect increases up to certain minor Drimia maritima content. Adsorption isotherms (e.g., Langmuir and Temkin) indicate that all three examined materials comprise physical adsorption mechanisms. Al-Si alloys attained inhibition efficiencies of about 96% at 25 °C with 1250 ppm of Drimia maritima and ~43% with 625 ppm at 45 °C. On the other hand, the cp. Al and SAE 1020 samples attain ~89% and 68% with 1250 ppm and 500 ppm at 25 °C, respectively. This clearly indicates that the dosage of Drimia maritima green inhibitor into NaCl solution possesses certain susceptibility for each distinctive material examined. Impedance parameters obtained by using CNLS (complex non-linear least squares simulations) are correlated and discussed. [ABSTRACT FROM AUTHOR]

A family of TiHfZrNb high-entropy alloys has been considered novel biomaterials for high-performance, small-sized implants. The present work evaluates the role of niobium on passivation kinetics and electrochemical characteristics of passive film on TiHfZrNb alloys formed in Hanks' simulated body fluid by analyzing electrochemical data with three analytical models. Results confirm that higher niobium content in the alloys reinforces the compactness of the passive film by favoring the dominance of film formation and thickening mechanism over the dissolution mechanism. Higher niobium content enhances the passivation kinetics to rapidly form the first layer, and total surface coverage reinforces the capacitive-resistant behavior of the film by enrichment with niobium oxides and reduces the point defect density and their mobility across the film, lowering pitting initiation susceptibility. With the high resistance to dissolution and rapid repassivation ability in the aggressive Hanks' simulated body fluid, the TiHfZrNb alloys confirm their great potential as new materials for biomedical implants and warrant further biocompatibility testing. [ABSTRACT FROM AUTHOR]

Electrochemical paper-based analytical devices (ePADs) offer an innovative, low-cost, and environmentally friendly approach for real-time diagnostics. In this study, we developed a functional all-inkjet paper-based electrochemical immunosensor using gold (Au) printed ink to detect salivary cortisol. Covalent binding of the cortisol monoclonal antibody onto the printed Au surface was achieved through electrodeposition of 4-carboxymethylaniline (CMA), with ethanolamine passivation to prevent non-specific binding. The ePAD exhibited a linear response within the physiological cortisol range (5–20 ng/mL), with sensitivities of 25, 23, and 19 Ω·ng/mL and R2 values of 0.995, 0.979, and 0.99, respectively. Additionally, interference studies against tumor necrosis factor-α (TNF-α) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) yielded excellent results. This novel ePAD, fabricated using inkjet printing technology on paper, simplifies the process, reduces environmental impact, and lowers fabrication costs. [ABSTRACT FROM AUTHOR]

Enzymatic fuel cells (EFCs) offer renewable energy conversion via highly selective electrode reactions using enzymes as natural catalysts even under mild conditions. Electrochemical impedance spectroscopy (EIS) is a valuable tool for evaluating EFC performance, providing insights into substrate mass transport, enzyme kinetics, and electrode stability. Despite its acknowledged importance, the use of EIS coupled with distribution of relaxation times (DRT) analysis in EFCs research is limited. Our study addresses this gap by employing EIS and DRT analysis to investigate enzyme‐based anodic processes, focusing on the bioelectrocatalytic oxidation of glucose catalyzed by glucose oxidase (GOx). Through careful variation of multiple parameters, it was possible to identify three distinct regions in the DRT plot. Each region has been subsequently associated with a key anodic process. The first region (R1) is associated with high‐frequency phenomena occurring at the electrodes, primarily due to ionic conduction in the electrolyte. Intermediate‐frequency processes are associated to charge transfer kinetics in region 2 (R2). Region 3 (R3) is linked to diffusion processes occurring at low frequencies. This thorough examination offers an insight into the functioning of enzymatic bioelectrodes, which in turn drives improvements in the design and components of biofuel cells to increase their power output. [ABSTRACT FROM AUTHOR]

Coronary plaque rupture remains the prominent mechanism of myocardial infarction. Accurate identification of rupture‐prone plaque may improve clinical management. This study assessed the discriminatory performance of electrochemical impedance spectroscopy (EIS) in human cardiac explants to detect high‐risk atherosclerotic features that portend rupture risk. In this single‐center, prospective study, n = 26 cardiac explants were collected for EIS interrogation of the three major coronary arteries. Vessels in which advancement of the EIS catheter without iatrogenic plaque disruption was rendered impossible were not assessed. N = 61 vessels underwent EIS measurement and histological analyses. Plaques were dichotomized according to previously established high rupture‐risk parameter thresholds. Diagnostic performance was determined via receiver operating characteristic areas‐under‐the‐curve (AUC). Necrotic cores were identified in n = 19 vessels (median area 1.53 mm2) with a median fibrous cap thickness of 62 μm. Impedance was significantly greater in plaques with necrotic core area ≥1.75 mm2 versus <1.75 mm2 (19.8 ± 4.4 kΩ vs. 7.2 ± 1.0 kΩ, p =.019), fibrous cap thickness ≤65 μm versus >65 μm (19.1 ± 3.5 kΩ vs. 6.5 ± 0.9 kΩ, p =.004), and ≥20 macrophages per 0.3 mm‐diameter high‐power field (HPF) versus <20 macrophages per HPF (19.8 ± 4.1 kΩ vs. 10.2 ± 0.9 kΩ, p =.002). Impedance identified necrotic core area ≥1.75 mm2, fibrous cap thickness ≤65 μm, and ≥20 macrophages per HPF with AUCs of 0.889 (95% CI: 0.716–1.000) (p =.013), 0.852 (0.646–1.000) (p =.025), and 0.835 (0.577–1.000) (p =.028), respectively. Further, phase delay discriminated severe stenosis (≥70%) with an AUC of 0.767 (0.573–0.962) (p =.035). EIS discriminates high‐risk atherosclerotic features that portend plaque rupture in human coronary artery disease and may serve as a complementary modality for angiography‐guided atherosclerosis evaluation. [ABSTRACT FROM AUTHOR]

A novel platform has been developed for the sensitive label-free detection of mutation in the TP53 gene, one of the most prominent genes in cancer research. The platform is based on the electrochemical properties of functionalized multi-walled carbon nanotubes (f-MWCNTs), gold nanoparticles (AuNPs), and polypyrrole (PPy). The microscopic structure and morphology of the prepared films on an ITO electrode surface were characterized using X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared (FTIR). The hybridization events specific to the TP53 gene were monitored using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The modified electrode, which incorporates vertically aligned f-MWCNTs arrays and AuNPs, exhibited enhanced probe DNA attachment density, improving the sensitivity of the DNA sensor. The combination of AuNPs/PPy with an in-situ produced f-MWCNTs array provides a viable strategy for developing a highly sensitive biosensor for fast mutation detection in human cancer types. [ABSTRACT FROM AUTHOR]

The distribution of relaxation times (DRT) method is an efficient approach for analyzing electrochemical impedance spectroscopy (EIS) of fuel cells. However, facing electrochemical processes with close characteristic times/frequencies, low frequency resolution of DRT puts a damper on the analysis of results. To address this problem, a new DRT method integrating elastic net regularization and quantum particle swarm optimization (QPSO) algorithm is proposed in this study. Elastic net regularization combines the advantages of Lasso's feature selection and Tikhonov's coefficient shrinkage, thereby enhancing the frequency resolution of DRT. The use of the QPSO algorithm avoids the manual selection of parameters. A comprehensive evaluation of the developed method is conducted using both synthetic EIS and experimental EIS. The results show that the developed DRT method shows good performance and the reconstructed DRT functions exhibit high frequency resolution and accuracy. Overall, the proposed DRT method holds promise for advancing the characterization of fuel cells. • A DRT method integrating elastic net regularization and QPSO algorithm is proposed. • The developed DRT method exhibits good performance in frequency resolution. • The developed DRT is free of adjusting parameters. [ABSTRACT FROM AUTHOR]

Implantable medical devices require protective encapsulation to isolate them from the biological environment. Parylene‐C (PaC) is a prevalent encapsulation polymer but is susceptible to cracking, delamination, oxidation, and moisture penetration over time. This study demonstrates that 3D micro‐anchors fabricated by direct laser writing (DLW) greatly enhance PaC lifetime and encapsulation properties. The PaC film is vapor deposited onto these anchor points, followed by ultraviolet radiation (UV)‐curing‐induced shrinkage. Electrochemical impedance spectroscopy (EIS) during accelerated aging tests in reactive solutions (87 °C, 15 mM H2O2) is performed to monitor film degradation over time. Unpatterned PaC films failed before reaching the 3.25 accelerated year benchmark, while 100 µm spaced micro‐anchors extended encapsulation up to 5.5 equivalent years. Subsequent improvements are achieved with a spacing of 50 µm, demonstrating viability up to ≈6 equivalent years. This research demonstrates the benefit of engineering anchor points for preventing delamination of the PaC layer and significantly enhancing encapsulation properties. Printed 3D micro‐anchors are an extremely flexible platform, with many different shapes and sizes possible which can further enhance longevity. The success in increasing coating lifetimes offers a promising direction for improving long‐term implantable medical devices, potentially revolutionizing their longevity and reliability. [ABSTRACT FROM AUTHOR]

Nanostructured CuS films were synthesized on FTO substrates employing low-cost electro deposition technique. XRD, Raman, SEM, UV–visible spectroscopy, photocurrent, PL, Mott-Schottky, and electrochemical impedance spectroscopy (EIS) measurements were used to examine physical and photoelectrochemical properties of samples. XRD results indicated that CuS films have hexagonal crystal structure where the crystallite size raises from 32 to 53 nm with increasing the Cu2+ molarity. Raman results displayed two peaks at 270 and 450 cm−1 that related to A1g transverse optical mode (TO) and A1g longitudinal optical (LO) mode for the vibrations of the S–S stretching and Cu–S bonds, respectively. SEM images displayed that fabricated CuS cover the substrate surface entirely, where grains are distributed uniformly with increasing the Cu+2 molarity. UV–visible measurements exhibited an absorption band edge between 450 and 550 nm as a characteristic of CuS films direct band gap. PL results presented strong blue-green emission at about 500 nm for CuS thin films. The photocurrent studies demonstrated that the CuS films are p-type semiconductors where the current density increases from 0.8 mA/cm2 to 1.1 mA/cm2 with the Cu2+ molarity increasing. The EIS analysis confirmed that charge transfer resistance reduces with increasing molarity. Mott- Schottky measurements established that carrier concentrations and the flat band varied from 5 × 1019 to 6.7 × 1019 cm−3 and from 1.1 to 0.75V, respectively. The fabricated CuS film was tested as glucose biosensor where a fast response and higher stability were noticed. Our results indicated that nanostructured CuS films are gifted candidates for optoelectronics applications especially biosensors. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the impact of cutting parameters on the corrosion resistance of micro-machined surfaces. Through a single-factor micro-cutting experiment and utilizing the CHI660E electrochemical workstation, the influence of different cutting parameters on cutting force, surface roughness, and corrosion resistance of machined surfaces of 7075 aluminum alloy is explored. The findings reveal that, when considering the same cutting parameters, higher cutting speeds result in lower surface quality compared to lower cutting speeds. The minimum surface roughness (Ra) value obtained is 0.187 μm, while the minimum corrosion current density for the sample with a cutting speed of 200 mm/s is 2.711 × 10−6 A cm−2, accompanied by the least amount of corrosion products on the machined surface. The cutting force demonstrates an almost linear increase with the growth of cutting depth, with the maximum cutting force recorded at 21.6N. Cutting depth proves to be the primary factor affecting workpiece surface roughness, with greater cutting depths resulting in higher surface roughness values, reaching a maximum of 0.327 μm (Ra). As the cutting depth increases from 20 to 40 μm, the self-corrosion potential of the samples shifts negatively by 22 mV, leading to a gradual weakening of their corrosion resistance. In terms of the feed rate, as it increases from 1.25 to 11.25 μm/z, the self-corrosion potential moves forward by 30 mV, resulting in a 51.2% decrease in current density and an overall enhancement in corrosion resistance. The optimal combination of cutting parameters determined from this study is a cutting speed of 200 mm/s, cutting depth of 20 μm, and feed rate of 3.75 μm/z. These findings provide valuable insights into the relationship between cutting parameters, surface quality, and corrosion resistance, aiding in the optimization of micro-machining processes for 7075 aluminum alloy. [ABSTRACT FROM AUTHOR]

Electric trains equipped with efficient electric motors and powered by high-capacity hydrogen fuel cells are a choice of the global transportation industry to accelerate the global transition to a low-carbon transportation system. The operation of distinct vehicle types in varying geographical regions is characterized by unique features. Concurrently, the continually fluctuating demand for electricity necessitates the utilization of fuel cells in conjunction with energy storage devices. Thus, this study centers on examining the role of the PEMFC-supercapacitor direct hybridization system within the authentic driving profile of the subway in the Bangkok metropolitan region. The supercapacitor within the hybridization system serves as an energy management device, enhancing the durability of fuel cells when subjected to diverse load demands associated with train propulsion. In order to validate this hypothesis, an MRT (Mass Rapid Transit) protocol was formulated to emulate and serve as the load demand for the investigation, and then the PEMFC-supercapacitor direct hybridization system was operated using the created profile. Subsequently, the hybridization system undergoes electrochemical characterizations and fuel cell performance tests for diagnostic purposes. Empirical findings validated that the supercapacitor operates as a filter, generating a stable voltage response to varying load requirements, and possesses the capability to assimilate energy originating from regenerative braking. The integration of supercapacitors in stabilizing the operational parameters of proton exchange membrane fuel cells (PEMFCs) has markedly prolonged their operational lifespan. This assertion is substantiated by voltage signal analysis, which demonstrated a negligible increase in surface resistance of merely 0.23%, as depicted by Nyquist plots. Furthermore, cyclic voltammetry revealed that the system attained a peak electrochemical surface area (ECSA) of 0.0089 (106 cm2/mg of Pt). The information presented in this article constitutes data that has been minimally explored in existing research. Specifically, the study concentrates on the practical driving pattern of electric trains. Consequently, experimental results were deemed advantageous for the advancement of heavy-duty electric vehicles. [Display omitted] • Exploring the relationship between the utilization of an energy storage device as a SC and energy generation as a PEMFC. • Establishing a connection between the authentic current profile of an MRT metro system and an accelerated stress test. • Examining the electrochemical reactions within fuel cells, drawing upon operational data from the transportation sector. [ABSTRACT FROM AUTHOR]

The common solution for protecting p‐type semiconductors against photocorrosion in a photo‐electrochemical (PEC) cell is by applying a TiO2 over‐layer via atomic layer deposition (ALD). However, for the case of CuBi2O4 (CBO), this approach leads to a significant decline in electrode performance, despite the small conduction band offset between CBO and TiO2. Here, electrochemical impedance spectroscopy (EIS) under light illumination is used to study how to enhance charge transport in CuBi2O4/TiO2 photocathodes. A 15 nm TiO2 overlayer enables a small charge transfer resistance to the electrolyte while preserving the performance and stability of the CBO film. When increasing the TiO2 thickness from 15 to 20 nm, the photogenerated currents decrease by 74%. The EIS data are fit with an equivalent circuit model that enabled to extract the charge transfer resistances, capacitances, and time constants that influence the PEC performance of the electrode as a function of the TiO2 layer thickness, together with the flat‐band potentials and doping densities of both the CBO and TiO2 layers under light illumination. The decline in performance is attributed to accumulation and recombination of photogenerated carriers at the CBO‐TiO2 interface, due to a band mismatch between the two semiconductors. [ABSTRACT FROM AUTHOR]

This paper focuses on long‐term tests held during 1,000 h on different Membrane‐Electrode‐Interconnect Assemblies (MEIAs), consisting of an Fe‐Ni alloy interconnect and an electrochemical cell based on a Ce0.8Sm0.2O2–δ electrolyte, the double‐layer working electrode with a La2NiO4 + δ – Ce0.8Sm0.2O2–δ composite functional layer, and a LaNi0.6Fe0.4O3–δ current collector layer, and a platinum reference electrode (O2, LaNi0.6Fe0.4O3–δ|La2NiO4 + δ – Ce0.8Sm0.2O2–δ|Ce0.8Sm0.2O2–δ|Pt, O2). These tests were carried out on MEIAs with the Cr‐free 47ND alloy of the Fe–Ni system with and without surface modification at 850°C in air. The electrochemical performance of MEIAs was studied without polarization as well as under cathodic and anodic polarization with current density 0.5 A cm−2 by means of electrochemical impedance spectroscopy (EIS). The mechanism of the MEIA evolution during long‐term test is discussed. [ABSTRACT FROM AUTHOR]

Using a chemiluminescence reaction between luminol and H2O2 in basic solution, an ultrasensitive electrochemiluminescence (ECL) aptasensor was developed for the determination of tobramycin (TOB), as an aminoglycoside antibiotic. Ti3C2/Ni/Sm-LDH-based nanocomposite effectively catalyzes the oxidation of luminol and decomposition of H2O2, leading to the formation of different reactive oxygen species (ROSs), thus amplifying the ECL signal intensity of luminol, which can be used for the determination of TOB concentration. To evaluate the performance of the electrochemiluminescence aptasensor and synthesized nanocomposite, different methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses were performed. The considerable specific area, large number of active sites, and enhanced electron transfer reaction on this nanocomposite led to the development of an ECL aptasensor with high sensitivity and electrocatalytic activity. After optimizing the preparation method and analysis conditions, the aptasensor revealed a wide linear response ranging from 1.0 pM to 1.0 μM with a detection limit of 18 pM, displaying outstanding accuracy, specificity, and response stability. The developed ECL sensor was found to be applicable to the determination of TOB in human serum samples and is anticipated to possess excellent clinical potentials for detecting other antibiotics, as well. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, affecting younger women and women of minorities. The nomenclature "triple negative" is derived from the absence of the three most common breast cancer biomarkers: progesterone receptor (PR), estrogen receptor (ER), and human epidermal growth factor receptor 2 (HER2). It derives its name from testing negative for these three most common breast cancer biomarkers. Currently, TNBC is diagnosed at advanced stages, necessitating the need for a diagnostic tool or method to identify this malignancy at an early stage prior to metastasis. In this study, a novel electrochemical biosensor was developed, optimized, and evaluated for the detection of microRNA-10b (miRNA-10b), marking the first use of this biomarker for the early diagnosis of TNBC. The biosensor demonstrated the ability to detect concentrations as low as 10 pM. Furthermore, the biosensor was specific toward the target biomarker, distinguishing non-target miRNAs of similar size. The efficacy of the biosensor for TNBC early diagnosis was further validated using human serum samples. [ABSTRACT FROM AUTHOR]

The application possibilities of austenitic stainless steels in high friction, abrasion, and sliding wear conditions are limited by their inadequate hardness and tribological characteristics. In order to improve these properties, the thermochemical treatment of their surface by plasma nitriding is suitable. This article is focused on the corrosion resistance of conventionally plasma-nitrided AISI 304 stainless steel (530 °C, 24 h) in 0.05 M and 0.5 M sodium chloride solutions at room temperature (20 ± 3 °C), tested by potentiodynamic polarization and electrochemical impedance spectroscopy. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy are used for nitrided layer characterization. The experiment results confirmed the plasma-nitrided layer formation of increased micro-hardness related to the presence of Cr2N chromium nitrides and higher surface roughness compared to the as-received state. Both of the performed independent electrochemical corrosion tests point to a significant reduction in corrosion resistance after the performed plasma nitriding, even in a solution with a very low chloride concentration (0.05 mol/L). [ABSTRACT FROM AUTHOR]

The effects of biodegradable corn peptone on the corrosion behavior of mild steel in 0.1M HCl were evaluated. The results from the weight loss experiments indicate that changing the amount of corn peptone from 50 to 500 ppm considerably decreased the corrosion rate of the coupons from 28.24 to 4.67 mpy. However, heating the solutions had negative effects on this trend. According to the calculations, dissolving the inhibitor modified the thermodynamic parameters of the corrosion phenomenon. In addition, the adsorption of corn peptone was best fitted with the Langmuir isotherm. The Tafel polarization plots revealed that the presence of corn peptone decreased the corrosion current density from 134.9 to 6.7 µA cm−2. This was compatible with the electrochemical impedance spectroscopy data. Furthermore, X‐ray photoelectron spectroscopy analysis confirmed the adsorption of the tested peptone on the surface of the working electrodes, which based on the atomic force microscope images, reduced the surface roughness of the specimens. [ABSTRACT FROM AUTHOR]

In this paper, self‐healing microcapsules were prepared by in situ polymerization using poly(vinyl alcohol) as the emulsifier, urea‐formaldehyde resin as the shell material, and alkyd resin as the core material. The average diameter of the obtained microcapsules was about 20 μm and the encapsulation rate of alkyd resin was 50.7 wt.%. The self‐healing coating was prepared by adding 5 wt.% of microcapsules to the pure polyurethane coating and then coated on AA2024‐T3 substrate. The self‐healing effect was evaluated by scanning electron microscopy. Electrochemical impedance spectroscopy tests and neutral salt spray tests confirmed that the self‐healing coating had good anticorrosion properties. [ABSTRACT FROM AUTHOR]

The negative electric potential difference observed in a YSZ-based thin film potentiometric sensor at a low operating temperature of 673 K is investigated. The multilayered sensor is grown sequentially using pulsed laser deposition at 998 K with Cu-Cu2O reference electrode, YSZ electrolyte and Pt as working electrode respectively. The thickness of the Cu-Cu2O reference layer is a critical factor in thin film sensors as the Pt3O4 phase stabilized along with Cu-Cu2O can reach the YSZ interface. XRD, μ- Raman and XPS confirm the formation of the Pt3O4 phase on the reference side along with the Cu-Cu2O layer. However, the pure Pt3O4 phase could not be stabilized in the thin film without Cu-Cu2O. The presence of the Pt3O4 phase on the reference side generates a Pt-Pt3O4 reference couple with an equilibrium oxygen partial pressure of ~ 104 ppm higher than the sample oxygen pressure of 10-103 ppm giving rise to a negative electric potential difference with a sensitivity of -7.5 mV/decade. [ABSTRACT FROM AUTHOR]

Extra virgin olive oil is a product with high commercial value mainly due to its unique quality and bioactive properties. It is commonly adulterated with other less expensive edible oils, making it necessary to develop and study rapid, cheap, and accurate analytical methods to identify extra virgin olive oil adulteration. In this respect, the current study aims to evaluate the application of electrochemical impedance spectroscopy to identify the adulteration of extra virgin olive oil with canola and sunflower oils. The experimental observations were processed through principal component analysis followed by hierarchical clustering to identify groups of treatments with similar behavior. Results have demonstrated that the approach could successfully classify the non-adulterated samples in a separate cluster in relation to the adulterated samples. An empirical equivalent electrical circuit parameter has suggested that the method is able to identify adulteration with 2% of the adopted edible oils and provided a clear distinction between the two adulterants. Overall, the study demonstrated the feasibility of the technique to identify the adulteration of extra virgin olive oil with the two adulterants. However, further studies are necessary to identify the limit of detection clearly and improve the quantification of adulterants added to the control samples. [ABSTRACT FROM AUTHOR]

Nanocrystalline yttria-stabilized zirconia (YSZ) was synthesized by a modified co-precipitation method. The process involves the use of molecular water associated with metal precursors to facilitate the hydroxylation. In this method, triethylamine was used to generate hydroxide ions from the molecular water of precursors, which helps to produce the metal hydroxides. Since no external water is utilized during the precipitation process, it is expected that the as-prepared and calcined materials should have minimum aggregation caused by the hydrogen bonding. The as-prepared and calcined YSZ powders are characterized by X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDX), Brunauer Emmett-Teller (BET), transmission and scanning electron microscopy (TEM and SEM) and electrochemical impedance spectroscopy (EIS). Cubic phase YSZ, having yttria content of 8 mol%, has been formed at a calcination temperature of 650°C. The YSZ powder has a surface area of 88 m2 g–1 and the particle diameters measured from TEM are in the range of 8–15 nm, which is in good agreement with the average particle diameter, which is ~12 nm, obtained from surface area. The materials produced have grain boundary oxygen ion conductivity of 0.073 S cm–1 at 800°C, which is one of the main parameters for SOFC to get higher power density. [ABSTRACT FROM AUTHOR]

Reduction of the nickel oxide-yttria stabilized zirconia (NiO-YSZ) anode is a significant step before the operation of a solid oxide fuel cell (SOFC). However, phenomena which occur during the reduction and their mechanism analyses are not summarized sufficiently. In this study, we investigated the influence of the hydrogen concentration, water vapor concentration of the reduction gas, Y2O3 content of the YSZ material of the anode, and temperature on the reduction process. The results showed that water vapor added to the hydrogen during reduction caused a temporary stasis period of the open circuit voltage. The length of the temporary stasis period was almost irrelevant to the water vapor concentration. During reduction, the length of the temporary stasis period of the open circuit voltage was negatively associated with hydrogen concentration and temperature, but positively associated with Y2O3 content of the YSZ material of the anode. After reduction, the SOFC showed better initial performance when the hydrogen concentration or the water vapor concentration during the reduction were higher. The classical shrinking core model can be used to explain these phenomena. [ABSTRACT FROM AUTHOR]

Neodymium‐doped amorphous LiFePO4/C cathodes formulated as LiFe1−xNdxPO4 (where x = 0, 0.02, 0.05, 0.08, labeled as LF1−xNxP) are synthesized by a solid‐station reaction. Herein, the influence of Nd doping on the amorphous structure, morphology, and electrochemical performance of LiFePO4/C is examined. The thermal and phase stability (ΔT) is analyzed using differential thermal analysis and proves thermal stability is enhanced by doping rare‐earth elements (Nd). The amorphous olivine LiFePO4 phase is identified from X‐ray diffraction peaks and it is demonstrated that neodymium carbon modification does not affect the structure of the sample but improves its kinetics in terms of discharge capacity and rate capability. The LF0.95N0.05P cathode shows the highest initial charge capacity (150 mAh g−1) and discharge capacity (147 mAh g−1) recorded at 0.1 C rate, the cyclic stability continues, and 91.33% of Coulombic efficiency even up to 500 cycles is achieved. The electrochemical impedance spectroscopy provides clearly that neodymium substituting reduces the charge transfer impedance and improves the lithium‐ion diffusion through the structure stability and the electrochemical performances of LiFePO4/C are highly improved by Nd doping. [ABSTRACT FROM AUTHOR]

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Commercially available 316L (1.4404) stainless steel is commonly used for industrial filtration due to its combination of good material properties, particularly its corrosion resistance, which is a critical factor for filters in corrosive (e.g., saltwater) environments. Recently, laser powder bed fusion (LPBF) has enabled new more complex and efficient filtration pieces to be manufactured from this material. However, it is critical to know how the corrosion resistance is affected by this manufacturing strategy. Here, the corrosion resistance of LPBF manufactured 316L stainless steel is compared with wrought 316L sheet. The corrosion of the samples in saltwater was assessed with asymmetric electrochemical noise, potentiodynamic polarisation curve, and electrochemical impedance spectroscopy. The samples before and after corrosion were examined with scanning electron microscopy and energy-dispersive spectroscopy. The LPBF samples had higher corrosion resistance than the sheet samples and were more noble. The corrosion resistance of the LPBF sample increased with time, while the wrought sample corrosion resistance reduced over time. The corrosion mechanism of both samples was stable with time, formed of a passive film process and a bared material process. This paper presents the first study about the temporal evolution of the LPBF 316L stainless steel corrosion mechanism. [ABSTRACT FROM AUTHOR]

Thin passive films on tungsten play an important role during the surface levelling of the metal for various applications and during the initial stages of electrochemical synthesis of thick, nanoporous layers that perform well as photo-absorbers and photo-catalysts for light-assisted water splitting. In the present work, the passivation of tungsten featuring metal dissolution and thin oxide film formation is studied by a combination of in situ electrochemical (voltammetry and impedance spectroscopy) and spectro-electrochemical methods coupled with ex situ surface oxide characterization by XPS. Voltametric and impedance data are successfully reproduced by a kinetic model featuring oxide growth and dissolution coupled with the recombination of point defects, as well as a multistep tungsten dissolution reaction at the oxide/electrolyte interface. The model is in good agreement with the spectro-electrochemical data on soluble oxidation products and the surface chemical composition of the passive oxide. [ABSTRACT FROM AUTHOR]

This study investigates the hydration behavior of cementitious materials incorporating fly ash, limestone and calcined clay (LC2), and seawater, aiming to understand the individual and synergistic effects of these components on hydration kinetics. The motivation behind this research lies in the growing interest in enhancing the performance and sustainability of cement-based materials by incorporating supplementary materials and utilizing seawater. To achieve this, the hydration process was meticulously examined using electrochemical impedance spectroscopy (EIS). An innovative equivalent circuit model was developed to analyze the results. The experimental data indicated that, with ongoing hydration, the diameter of the impedance arc in the high-frequency range gradually increases. A noteworthy observation is that increasing the proportion of fly ash and LC2 in the cement paste leads to a corresponding enlargement of the high-frequency arc, indicating a significant influence of these supplementary materials on the hydration process. Additionally, LC2 was found to be more effective in accelerating the hydration process compared to fly ash. [ABSTRACT FROM AUTHOR]

The rapid and accurate detection of SARS-CoV-2, particularly its spike receptor-binding domain (S-RBD), was crucial for managing the COVID-19 pandemic. This study presents the development and optimization of two types of aptasensors: quartz crystal microbalance (QCM) and electrochemical sensors, both employing thiol-modified DNA aptamers for S-RBD detection. The QCM aptasensor demonstrated exceptional sensitivity, achieved by optimizing aptamer concentration, buffer composition, and pre-treatment conditions, with a limit of detection (LOD) of 0.07 pg/mL and a linear range from 1 pg/mL to 0.1 µg/mL, and a significant frequency change was observed upon target binding. The electrochemical aptasensor, designed for rapid and efficient preparation, utilized a one-step modification process that reduced the preparation time to 2 h while maintaining high sensitivity and specificity. Electrochemical impedance spectroscopy (EIS) enabled the detection of S-RBD concentrations as low as 132 ng/mL. Both sensors exhibited high specificity, with negligible non-specific interactions observed in the presence of competing proteins. Additionally, the QCM aptasensor's functionality and stability were verified in biological fluids, indicating its potential for real-world applications. This study highlights the comparative advantages of QCM and electrochemical aptasensors in terms of preparation time, sensitivity, and specificity, offering valuable insights for the development of rapid, sensitive, and specific diagnostic tools for the detection of SARS-CoV-2 and other viruses. [ABSTRACT FROM AUTHOR]