Electrochemical Impedance Spectroscopy Measurements Research Articles

Modulating electrical response and impedance in Co–Cr substituted M-phase barium hexaferrites: Examining microstructure, grain boundaries, charge transport, and computational modeling

This study explores the influence of Co2+ and Cr3+ doping on the microstructure and electrical properties of Ba-hexagonal ferrite synthesized using the sol-gel method. X-ray diffraction (XRD) confirmed the formation of the anticipated hexagonal M-type crystal structure. Field emission scanning electron microscopy (FESEM) revealed the evolution of grain morphology with increasing doping levels, showcasing the formation of needle-like grains. Electrical characterization using an impedance analyzer investigated dielectric, impedance, electric modulus, and conductivity properties at room temperature. The analysis of the dielectric spectra indicated a decrease in dielectric constant and an increase in loss tangent with increasing dopant concentration. The electric modulus spectra provided evidence for non-Debye relaxation behavior, further supported by observations of relaxation processes at varying frequencies in the conductivity spectra. Additionally, an increase in doping led to a decrease in both relaxation time and AC conductivity. Electrochemical impedance spectroscopy (EIS) measurements yielded complex impedance curves. These curves exhibited good agreement with the values obtained through software-based simulations of grain and grain boundary characteristics. Furthermore, the distribution of grains and grain boundaries observed in FESEM micrographs aligned with the patterns predicted by the EIS software.

Mg-Ti hybrid joints: Surface modification, corrosion studies and 3D-pore investigation using synchrotron-based microtomography

A new direction toward the future of orthopedic implants is to combine biodegradable Mg alloys with permanent Ti to produce selectively biodegradable hybrid joints for advanced tissue engineering. However, the strong galvanic corrosion between Mg and Ti is a major issue to be considered. This work aims to explore plasma electrolytic oxidation (PEO) as a single-step coating treatment to allow for an acceptable degradation behavior of MgTi hybrid systems. To this end, MgTi hybrid joints were produced through the heat treatment of Mg-0.6Ca and commercially pure Ti specimens at 640 °C for 8 h. A single-step PEO treatment was then employed to create a protective layer on the surface of hybrid couples. Even though the scanning electron microscopy (SEM) images showed only a porosity of 6% and 12% within the PEO layers on single Mg and MgTi couples, 3D investigation of the synchrotron-based microtomography data demonstrated a porosity of 18% and 30% with a considerable number of interconnected pores. According to the electrochemical impedance spectroscopy measurements, the impedance modulus at all frequencies on coated MgTi coupled specimens was lower than that on the coated single Mg-0.6Ca and pure Ti. However, the application of PEO treatment significantly decreased the strong galvanic degradation of Mg-0.6Ca in contact with Ti. The results of hydrogen evolution tests revealed that PEO-treated MgTi couples showed a similar degradation behavior as the single alloy during the first day of immersion.

Research on anti-corrosion behavior of modified waterborne Acrylic-based coating containing CuO/Polyaniline nanocomposite on mild steel in 3.5 wt% NaCl solution

This research examines the anti-corrosion properties of an acrylic coating containing CuO/Polyaniline nanocomposite (CuO/PANI n-composite) and the effect of different composition percentages of the n-composite. Electrochemical tests were carried out on mild steel alloy in 3.5 % NaCl solution for 60 days in a saline environment. The electrochemical current noise (ECN) results of prepared coatings were interpreted using the wavelet method. The standard deviation of partial signal (SDPS) plots derived from wavelet, as well as the electrochemical impedance spectroscopy (EIS) technique demonstrated that the quantity of electric charge (Q) decreased with the addition of the n-composite, due to the decreased corrosion rate. Moreover, the modified coating with 20 % composition of the n-composite demonstrated more inhibiting effects in a short and long time compared to other compositions. The EIS measurements showed that the value of coating resistance for 20 % CuO/Polyaniline nanocomposite after 1 day immersion is 1510 kΩ cm2. The results indicated that the 20 % composition of the n-composite exhibited excellent inhibiting properties with an efficiency of 97.57 % and 97.62 % after 1 and 60 Immerging time/day, respectively. The prepared n-composite has been characterized using X-ray diffraction (XRD) analysis, Field-Emission Scanning Electron Microscopy (FE-SEM), and Transmission Electron Microscopy (TEM), which revealed suitable synthesis of the CuO/PANI n-composite. Therefore, this research demonstrates a successful approach to developing the anti-corrosion effect of acrylic coating by the incorporation of CuO/PANI n-composite.

Microwave-Assisted Ultrafast Synthesis of Bimetallic Nickel-Cobalt Metal-Organic Frameworks for Application in the Oxygen Evolution Reaction.

Herein, a series of monometallic Ni-, Co- and Zn-MOFs and bimetallic NiCo-, NiZn- and CoZn-MOFs of formula M2(BDC)2DABCO and (M,M')2(BDC)2DABCO, respectively, (M, M'=metal) with the same pillar and layer linkers 1,4-diazabicyclo[2.2.2]octane (DABCO) and benzene-1,4-dicarboxylate (BDC) were prepared through a fast microwave-assisted thermal conversion synthesis method (MW) within only 12 min. In the bimetallic MOFs the ratio M:M' was 4 : 1. The mono- and bimetallic MOFs were selected to systematically explore the catalytic-activity of their derived metal oxide/hydroxides for the oxygen evolution reaction (OER). Among all tested bimetallic MOF-derived catalysts, the NiCoMOF exhibits superior catalytic activity for the OER with the lowest overpotentials of 301 mV and Tafel slopes of 42 mV dec-1 on a rotating disk glassy carbon electrode (RD-GCE) in 1 mol L-1 KOH electrolyte at a current density of 10 mA cm-2. In addition, NiCoMOF was insitu grown in just 25 min by the MW synthesis on the surface of nickel foam (NF) with, for example, a mass loading of 16.6 mgMOF/gNF, where overpotentials of 313 and 328 mV at current densities of 50 and 300 mA cm-2, respectively, were delivered and superior long-term stability for practical OER application. The low Tafel slope of 27 mV dec-1, as well as a low reaction resistance from electrochemical impedance spectroscopy (EIS) measurement (Rfar=2 Ω), confirm the excellent OER performance of this NiCoMOF/NF composite. During the electrocatalytic processes or even before upon KOH pre-treatment, the MOFs are transformed to the mixed-metal hydroxide phase α-/β-M(OH)2 which presents the active species in the reactions (turnover frequency TOF=0.252 s-1 at an overpotential of 320 mV). Compared to the TOF from β-M(OH)2 (0.002 s-1), our study demonstrates that a bimetallic MOF improves the electrocatalytic performance of the derived catalyst by giving an intimate and uniform mixture of the involved metals at the nanoscale.

Innovative Nanocomposite Coating for Aluminum Alloy in the Aircraft Manufacturing Industry with Increased Mechanical Strength, Flame Retardancy, and Corrosion Resistance

AbstractNanocomposites containing impermeable two‐dimensional materials are of significant interest for protecting metals against corrosion. Incorporating 4‐aminobutyltriethoxysilane (ABES) functionalized tantalum nitride (TaN) into a coating matrix enhances the barrier effect due to TaN's notable chemical and thermal stability. When integrated with graphitic carbon nitride (GCN) in polyurethane (PU), functionalized TaN significantly improves corrosion resistance and fire‐retardant capabilities. Electrochemical evaluations of aluminum coated with varying amounts of functionalized TaN/GCN in PU demonstrated substantial enhancements in protective behavior in chloride environments. The PU nanocomposite exhibited superior flame retardancy, with significant reductions in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) compared to pure PU. Flame retardancy tests demonstrated increased thermal stability, attributed to the synergistic effects between GCN and silanized TaN. Electrochemical impedance spectroscopy (EIS) measurements showed a high coating resistance of 8.89×1011 Ω cm2 for PU/functionalized TaN/GCN, even after 40 days of electrolyte exposure. Additionally, the PU/functionalized TaN/GCN coating demonstrated exceptional water repellency, indicated by a water contact angle (WCA) of 164°. Mechanical tests revealed that PU/functionalized TaN/GCN exhibited favorable adhesion strength and hardness, maintaining integrity even under prolonged immersion. These findings suggest that this nanocomposite is a promising coating component for aerospace applications. The integration of functionalized TaN/GCN within the PU matrix presents a novel approach to developing multifunctional coatings with enhanced performance across various metrics essential for aerospace materials.

Effectiveness of expired estradiol valerate drug molecule as a corrosion inhibitor for mild steel in 1 M HCl medium: Waste utilization perspective

This study explores the utilization of expired pharmaceutical drugs, specifically Progynova 2 mg (estradiol valerate), as a sustainable solution for corrosion inhibition in mild steel exposed to a 1 M HCl medium at 30 °C. Through a comprehensive analysis employing FTIR, mass loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), quantum chemical analysis (DFT), and scanning electron microscopy (SEM), the research confirms the remarkable effectiveness of estradiol valerate (EPROG) in inhibiting mild steel corrosion, achieving an impressive 94.27 % inhibition efficiency at a concentration of 600 ppm. Potentiodynamic polarization reveals mixed-type inhibition behavior, while EIS measurements indicate increased charge transfer resistance (Rct) and reduced double layer capacity (Cdl) with higher estradiol valerate concentrations, in line with Langmuir adsorption isotherm results. The DFT analysis of the EPROG inhibitor indicates that it use a donor-acceptor mechanism to interact with the metal surface. SEM analysis further substantiates the presence of a stable EPROG inhibitor layer on the mild steel surface, underscoring its corrosion inhibition properties and advocating for the sustainable repurposing of expired pharmaceuticals in environmental and structural preservation efforts.

Low-temperature fabrication of morphology-controllable Cu2O for electrochemical CO2 reduction

Cu2O has been successfully synthesized in different morphologies/sizes (nanoparticles and octahedrons) via a low-temperature chemical reduction method. Trapping metal ions in an ice cube and letting them slowly melt in a reducing agent solution is the simplest way to control the nanostructure. Enhancement of charge transfer and transportation of ions by Cu2O nanoparticles was shown by cyclic voltammetry and electrochemical impedance spectroscopy measurements. In addition, nanoparticles exhibited higher current densities, the lowest onset potential, and the Tafel slope than others. The Cu2O electrocatalyst (nanoparticles) demonstrated the Faraday efficiencies (FEs) of CO, CH4, and C2H6 up to 11.90, 76.61, and 1.87%, respectively, at −0.30 V versus reference hydrogen electrode, which was relatively higher FEs than other morphologies/sizes. It is mainly attributed to nano-sized, more active sites and oxygen vacancy. In addition, it demonstrated stability over 11 h without any decay of current density. The mechanism related to morphology tuning and electrochemical CO2 reduction reaction was explained. This work provides a possible way to fabricate the different morphologies/sizes of Cu2O at low-temperature chemical reduction methods for obtaining the CO, CH4, and C2H6 products from CO2

Differential impedance analysis — Extensions and applications in machine learning

The technique of differential impedance analysis (DIA) has shown promising results in identifying appropriate model orders when applied to electrochemical impedance spectroscopy (EIS) measurements of a given medium. However, even with this method it remains challenging to reliably deduce general material properties of the medium from impedance data alone. Here, we discuss a number of possible extensions and modifications of the technique and, in particular, an extension of the process from mere model order identification to a complete modelling approach. In addition, the combination of DIA and machine learning methods to predict material properties is explored. Our results were validated with impedance measurements between 20Hz and 1MHz of moulding sand containing varying amounts of quartz and chromite sand as well as bentonite and carbon.

Cobalt removal process from PDC with ultrasonication in neutral electrolyte

Cobalt removal is considered a common method to improve the performance of polycrystalline diamond compact (PDC). To effectively reduce the pollution during the process of cobalt removal, a neutral electrolyte was used in this work to remove cobalt from PDC by electrolysis with ultrasonication. The electrode process and mass transfer model of cobalt removal in a NaCl–KCl solution were established by performing electrochemical impedance spectroscopy (EIS) measurements. Different electrode potentials and electrolytic durations were set to investigate the limits of cobalt removal in the neutral electrolyte. Cobalt removal was assessed by conducting potentiodynamic polarisation, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements. The ImageJ2x image analysis software was used to study the collected spectra. The experimental results indicated that cobalt was successfully removed in the neutral electrolyte and that ultrasonication enhanced its removal. The optimal electrode potential for cobalt removal in the NaCl–KCl solution was less than 500 mV or more than 2000 mV. As the electrolysis time increased, the porosity of the PDC surface first increased to 9.4 % and then decreased to 7.2 %, and the depth of cobalt removal was up to 224 μm. Over time, the rate of cobalt removal decreased, suggesting that the efficacy of ultrasonication in promoting the cobalt removal process gradually weakened as electrolysis products continued to accumulate.

One-pot synthesis of N'-(thiophen-2-ylmethylene)isonicotinohydrazide Schiff-base as a corrosion inhibitor for C-steel in 1 M HCl: Theoretical, electrochemical, adsorption and spectroscopic inspections

Although carbon steel (CS) is an essential component utilized in many industries, it regrettably corrodes when exposed to acidic conditions. Schiff bases have recently become more concerned with the corrosion prevention of CS. Hydrazides and the related compounds shown to be effective inhibitors of CS corrosion in acids. These compounds are commonly employed as origins or intermediates to several key molecules in the synthesis of organic compounds, and they are highly sought after due to their wide range of biological and therapeutic applications. They have anti-bacterial, anti-malarial, anti-fungal, and anticancer properties, as well as corrosion protection. Hence, the inhibitory effectiveness of a new synthesized (E)-N'-(thiophen-2-ylmethylene) isonicotinohydrazide (TMNH) Schiff-base for the corrosion of CS in 1 M HCl was explored. The structure of TMNH was validated by FT-IR and 1H NMR spectroscopy. A number of chemical, spectral, and electrochemical techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and mass loss (ML) have been used to evaluate its anticorrosion power. PDP measurements showed that it is a mixed-type inhibitor. In addition, EIS measurements showed that Rct increased sharply from 37 without the corrosion inhibitor to 589 Ω cm-2 in the presence of 1 mM TMNH and from PDP scans, the corresponding icorr decreased dramatically from 0.6158 to 0.0314 μA cm-2. ML tests have proven their effectiveness, achieving an inhibitory efficiency of 95.3 %. Adsorption studies were also conducted to determine the nature of the corrosion retardation mechanism. The TMNH inhibitor was spontaneously chemically/physically adsorbed onto the CS surface following the Langmuir isotherm. Statistical calculations were also applied to verify the accuracy of the experimental results. The Monte Carlo model showed that the inhibitory molecules adsorbed flat on only one side, increasing the chances of adsorption.

PEDOT-Doped Mesoporous Nanocarbon Electrodes for High Capacitive Aqueous Symmetric Supercapacitors.

Poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT-functionalized carbon nanoparticles (f-CNPs) were synthesized by in situ chemical oxidative polymerization and pyrolysis methods. f-CNP-PEDOT nanocomposites were prepared by varying the concentration of PEDOT from 1 to 20% by weight (i.e., 1, 2.5, 5, 10, and 20 wt%). Several characterization techniques, such as field-emission scanning electron microscopy (FESEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), N2 Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses, as well as cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS), were applied to investigate the morphology, the crystalline structure, the N2 adsorption/desorption capability, as well as the electrochemical properties of these new synthesized nanocomposite materials. FESEM analysis showed that these nanocomposites have defined porous structures, and BET surface area analysis showed that the standalone f-CNP exhibited the largest surface area of 801.6 m2/g, whereas the f-CNP-PEDOT with 20 wt% exhibited the smallest surface area of 116 m2/g. The BJH method showed that the nanocomposites were predominantly mesoporous. CV, GCD, and EIS measurements showed that f-CNP functionalized with 5 wt% PEDOT had a higher capacitive performance compared to the individual f-CNPs and PEDOT constituents, exhibiting an extraordinary specific capacitance of 258.7 F/g, at a current density of 0.25 A/g, due to the combined advantage of enhanced electrochemical activity induced by PEDOT doping, and highly developed porosity of f-CNPs. Symmetric aqueous supercapacitor devices were fabricated using the optimized f-CNP-PEDOT doped with 5 wt% of PEDOT as active material, exhibiting a high capacitance of 96.7 F/g at 1.4 V, holding practically their full charge, after 10,000 charge-discharge cycles at 2 A/g, thus providing the highest electrical electrodes performance. Hereafter, this work paves the way for the potential use of f-CNP-PEDOT nanocomposites in the development of high-energy-density supercapacitors.

Walnut (Juglans regia L.) fruit septum alcoholic extract as corrosion inhibitor for Fe B500B steel bars in mixed acidic solution

The corrosion inhibition performance of the walnut fruit (Juglans regia L.) septum alcoholic extract for Fe B500B steel bars in a mixed acidic solution (H2SO4/HCl) is reported. Weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy measurements were performed at 298 to 318 K, with the addition of various extract concentrations. Results showed the maximum corrosion inhibition efficiency of 86.99 % for 300 mg L-1 extract added. The extract acts as a mixed-type inhibitor, predominantly affect­ing the anodic side, following Flory-Huggins adsorption isotherm. Thermodynamic analysis indicated an endothermic process with both chemisorption and physisorption on the steel bar surface. Surface characterization was conducted using ATR-FTIR, UV-vis and SEM techniques to prove the adsorption of the inhibitor molecules on the steel bar surface. Also, a possible adsorption mechanism of inhibitor molecules was proposed.

Development of ultra-sensitive and selective molecularly imprinted polymer-based electrochemical sensor for L-lactate detection

Lactate detection is important for the food and healthcare industries, and it’s especially important when there’s tissue hypoxia, hepatic illness, bleeding, respiratory failure, or sepsis. A new molecularly imprinted polymer (MIP) based electrochemical sensor was fabricated for differential pulse voltammetric assay of L-lactate (LAC). By using ZIF-8@ZnQ nanoparticles, the number of regions and effective surface area were increased. The polymeric film was obtained using 4 aminobenzoic acid (4-ABA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, 2-hydroxyethyl methacrylate (HEMA) as basic monomers, and 2-hydroxy-2-methylpropiophenone one as initiator. The developed 4-ABA/LAC/ZIF-8@ZnQ@MIP-GCE was morphologically characterised using SEM and electrochemically using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements. A linear range of 0.1–1.0 pM LAC with a detection limit of 29.9 fM was found. Lastly, the MIP-based electrochemical sensor detected LAC in commercial human serum samples.

Electrochemical Impedance of Well-Passivated Semiconductors Reveals Bandgaps, Fermi Levels, and Interfacial Density of States.

For well-passivated semiconductor materials, the density of states (DOS) at the band edge determines the concentration of electrons (or holes) available to participate in photo/electrochemical redox and chemical reactions. Electrochemical impedance enables the characterization of photo-electrode DOS in a functional, in situ, electrochemical environment. However, the in situ electrochemical approach remains underutilized for band structure characterization of inorganic semiconductors. In this work, we demonstrate that the DOS of the well-passivated, highly ordered semiconductors silicon and germanium is directly probed by electrochemical impedance spectroscopy (EIS). More specifically, EIS measurements of the chemical capacitance in contact with electrolyte enable direct analysis of the DOS properties. From the capacitance-potential plot, the following parameters can be extracted: Fermi level, valence band maximum, conduction band minimum, and a quantitative value of the number of states at each potential. This study aims to establish the groundwork for future EIS investigations of electronically modified semiconductor interfaces with covalently bound organic molecules, organometallic catalysts, or more complex biorelated functionalizations.

Towards a scalable production of β-Li3PS4-based all-solid-state batteries: Optimizing pressing parameters of the tape-casted solid electrolyte and composite cathode films

Pressing of all-solid-state batteries (ASSBs) components is one of the most important processes for scalable production. Henceforth, pressing parameters (pressure and temperature) for β-Li3PS4 (β-LPS) solid electrolyte (SE) separator films and LiNi0.6Co0.2Mn0.2 (NCM622)/β-LPS composite cathode films prepared by a slurry-based process were investigated and optimized. Compression of the β-LPS film at a temperature of 100 °C led to higher ionic conductivity than cold-pressed films. Raman and X-ray photoelectron spectroscopic analyses revealed no changes in the chemical nature of β-LPS material after hot pressing. Interestingly, time-of-flight secondary ion mass spectrometric (ToF-SIMS) analyses indicated a binder enrichment in the upper layers of the hot-pressed film. In a similar trend, increasing compression and temperature resulted in higher densification of NCM622/β-LPS composite cathode films. Based on galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) measurements, hot-pressed composite cathode at 200 MPa/100 °C exhibited a higher coverage percent of catholyte on cathode active material and a greater Li+ diffusion coefficient (DLi+) than cold-pressed one at 200 MPa/20 °C. Cycling tests of “Li–In│β-LPS│NCM/β-LPS” ASSBs with hot-pressed films displayed better cycling performance than that with cold-pressed ones, attributed to the higher concentration of electrochemically active NCM in close contact with β-LPS catholyte.

Facile synthesis, enhanced annealing-structural investigation and supercapacitive potentials of NiFe2O4 spinel nanopowder

Herein, we examined and optimized the influence of annealing temperature on microstructural and electrochemical charge storage properties of spinel NiFe2O4 nanopowder synthesized from a simple one-pot sol-gel route. Microstructural techniques encompassing Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffractometry, and Fourier transform infra-red spectroscopy indicate the resulting powder are composed of spinel NiFe2O4 nanoparticle with metal oxygen vibration, crystal properties and lattice strain, all dependent on annealing temperature. Electrochemical charge storage performance of the electrode fabricated from the synthesized material were investigated with the aid of cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy measurements. The obtained results showed that the charge storage performance and rate capability of NiFe2O4 electrode is dependent on the annealing temperature. The study also showed that the electrode from the material annealed at 400 °C demonstrated optimum electrochemical charge storage performance having exhibited optimum specific capacitance and capacity values of 1128 Fg−1 and 58 mAh g−1 at 5 mVs−1 scan rate and 0.5 Ag−1 current density, respectively. The electrode EIS fitted equivalent circuit values were also found dependent on annealing temperature indicating the charge transfer process and rate capability of spinel NiFe2O4 nano-powder can be tailored by simply varying the annealing temperature. The study demonstrates cheap route by which spinel NiFe2O4 powder can be prepared. It also unveils the effect annealing temperature on the microstructural build-up and electrochemical charge storage performance of the material.

A 0.05%–0.08% THD, 762.9 Hz–10 MHz direct digital frequency synthesizer using a reconfigurable DAC for electrochemical impedance spectroscopy measurements

A 0.05%–0.08% THD, 762.9 Hz–10 MHz direct digital frequency synthesizer using a reconfigurable DAC for electrochemical impedance spectroscopy measurements

Detection of Crude Oil in Subsea Environments Using Organic Electrochemical Transistors.

Current methods for detecting pipeline oil leaks depend primarily on optical detection, which can be slow and have deployment limitations. An alternative non-optical approach for earlier and faster detection of oil leaks would enable a rapid response and reduce the environmental impact of oil leaks. Here, we demonstrate that organic electrochemical transistors (OECTs) can be used as non-optical sensors for crude oil detection in subsea environments. OECTs are thin film electronic devices that can be used for sensing in a variety of environments, but they have not yet been tested for crude oil detection in subsea environments. We fabricated OECTs with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) as the channel and showed that coating the channel with a polystyrene film results in an OECT with a large and measurable response to oil. Oil that comes in contact with the device will adsorb onto the polystyrene film and increases the impedance at the electrolyte interface. We performed electrochemical impedance spectroscopy measurements to quantify the impedance across the device and found an optimal thickness for the polystyrene coating for the detection of oil. Under optimal device characteristics, as little as 10 μg of oil adsorbed on the channel surface produced a statistically significant change in the source-drain current. The OECTs were operable in seawater for the detection of oil, and we demonstrated that the devices can be transferred to flexible substrates which can be easily implemented in vehicles, pipelines, or other surfaces. This work demonstrates a low-cost device for oil detection in subsea environments and provides a new application of OECT sensors for sensing.

Vanillin‐Based Photocurable Anticorrosion Coatings Reinforced with Nanoclays

AbstractThis study investigates the chemical–physical properties and anticorrosion effectiveness of UV‐cured coatings produced using epoxidized vanillin (DGEVA) as biobased precursor, then reinforced by the addition of nanoclay. After optimizing the UV‐curing parameters of three different formulations by Fourier transform infrared spectroscopy (FTIR), the thermo‐mechanical properties of the coatings are assessed by differential scanning calorimetric analysis (DSC), dynamic thermal mechanical analysis (DTMA), and pencil hardness. The coatings are applied on mild steel substrates and then their barrier properties are investigated by electrochemical impedance spectroscopy measurements, immersing the samples in 3.5 wt% NaCl aerated solutions. The results show the good corrosion protective effectiveness of the biobased coatings. The nanoclay addition has a beneficial effect, as it hinders the diffusion of the aggressive ions from the electrolyte solution to the metal substrate. The reported findings demonstrate the possibility of using biobased precursors and UV‐curing technology to reduce the environmental impact of the coating industry.

Electrochemical Kinetic Behaviors and Sensing Performance of Au@ZIF-8 and Ag@ZIF-8 Nanocomposites-Based Platforms Towards Ultrasensitive Detection of Chloramphenicol

Silver (Ag) and gold (Au) nanoparticles (NPs) are incorporated into the zeolitic imidazolate framework-8 (ZIF-8) host matrix, which is successfully coated the screen-printed electrodes (SPEs) for the effective detection of chloramphenicol (CAP). The morphological and structural characteristics are examined using scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. Additionally, the electrochemical characteristics and sensing performance of CAP on the proposed electrodes are investigated in detail using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), and differential pulse voltammetry (DPV) measurements, respectively. The results suggest the SPEs modified with Ag@ZIF-8 and Au@ZIF-8 exhibit impressive enhancements in sensitivity, linear concentration range, limits of detection (LODs), and repeatability. Under the optimum conditions, the proposed electrochemical sensors had a linear range of 0.25–50 μM for Ag@ZIF-8/SPE and 5–50 μM for Au@ZIF-8/SPE, corresponding to LODs of 0.16 and 0.404 μM, respectively. Notably, a series of kinetic parameters related to the redox reactions of both standard Fe(CN)6 3−/4− probe and CAP molecules in phosphate-buffered saline (PBS) buffer are determined. Furthermore, valuable insights into the influence mechanism nature of Ag@ZIF-8 and Au@ZIF-8 nanocomposites on the electrochemical behaviors are proposed, demonstrating the great potential of the developed sensors for CAP detection.