Search

A frequency-dependent dielectric constant characterizes the dielectric response of a medium and also represents the time scale of system's collective dynamics. Although it is valuable not only academically but also practically for developing advanced devices, getting the value of a solution at the interface with a solid or electrode surface is challenging both experimentally and computationally. Here, we propose a computational method that imitates the dielectric spectroscopy and AC impedance measurement. It combines a time-dependent voltage applied molecular dynamics simulation with an equivalent circuit representation of a system composed of a solution confined between two identical electrodes. It gives the frequency-dependent dielectric constants of the bulk solution and the interface simultaneously. Unlike the conventional method, it does not require computation of a dipole autocorrelation function and its Fourier transformation. Application of the method on a system of water confined between polarizable Pt electrodes gives the static dielectric constant and the relaxation time of the bulk water in good agreement with previous simulation results and experimental values. In addition, it gives a much smaller static dielectric constant at the interface, consistent with previous observations. The outline of the dielectric dispersion curve of the interface seems similar to that of the bulk, but the relaxation time is several times faster. [ABSTRACT FROM AUTHOR]

In this research, we explore sequence-dependent chiral-induced spin selectivity (CISS) in double-stranded (ds)-DNA using time-correlated single-photon counting and electrochemical impedance spectroscopy supplemented by tight-binding calculations of the phenomenon for the first time. The average lifetime of the photo-excited electrons in a Quantum Dot-DNA system is influenced by the CISS effect generated by the DNA molecule, and the difference in average time decay of electrons was found to be 345 ps for opposite polarity ("UP" and "DOWN") of spins due to the CISS effect. Moreover, the yield of spin-polarized electrons due to the CISS effect was reduced by more than 35% from perfect DNA to DNA with point mutations. Remarkably, by employing a tight binding method combined with Green's function formalism for transport, simulations of the process support the observed experimental trends. Our results provide a basic understanding of the sequence-specific spin-dependent electron transfer through ds-DNA. These results would help to build spin-based next-generation DNA sensors. [ABSTRACT FROM AUTHOR]

This study investigated the charge injection and accumulation characteristics of organic light-emitting diodes (OLEDs) generated by spontaneous orientation polarization (SOP) of organic molecules. SOP enhances the electrical characteristics of OLED devices, such as charge injection and transport, by adjusting the interfacial charge density between the organic layers within the device. An OLED device with a mixed co-host emitting layer was fabricated to examine the degradation effect of SOP after electrical aging. Impedance spectroscopy (IS) revealed the presence of interfacial charges originating from the SOP of small molecules within the electron transport layer (ETL), in both pristine and aged devices. Furthermore, the IS simulation results using equivalent circuits were successfully interpreted based on the electrical properties of each organic layer in the pristine and aged devices. The electrical properties of the ETL, which contained 1,3,5-tris(N-phenyl benzimidazole-2-yl)benzene (TPBi), were degraded, reducing hole accumulation and electron injection.

Cu2+ and Er3+ doped BaZr0.05Ti0.95O3 (BZT) ceramics were prepared using the solid-state reaction method, where amount of CuO + Er2O3 was fixed at 2 wt.% and different CuO : Er2O3 molar ratios (i.e. 1:1, 1:2, 1:3, 2:1 and 3:1) were used. The influence of Cu2+ and Er3+ doping on crystal structure and dielectric properties of the samples sintered at 1300 °C was investigated. X-ray diffraction analysis confirmed the formation of a single-phase material and tetragonal crystal structure with P4mm symmetry. Microstructural analysis conducted with a scanning electron microscope revealed well-defined and uniformly distributed grains across the surface of the sintered samples and reduction of grain size and density with doping. The highest energy storage density of 40.51mJ/cm3 with an energy efficiency of 78.8% was obtained in the sample with CuO : Er2O3 molar ratio of 2:1. The doped BZT ceramics have high dielectric constant and significantly lower tangent loss in comparison to the undoped BZT. The dielectric data confirm the non-Debye behaviour for all the samples. Impedance spectroscopy and electrical modulus analysis indicated that conduction in the materials was influenced by both the grains and grain boundaries. The AC conductivity is described by the Jonscher’s universal power law, whereas DC conductivity follows a dependency based on the Arrhenius’s theory. The results revealed a conduction mechanism characterized by non-overlapping small Polaron tunnelling up to 340°C and a transition to correlated barrier hopping conduction above 340°C within the selected temperature range for all the samples. According to the Arrhenius fitting of DC conductivity the activation energy of the undoped BaZr0.05Ti0.95O3 sample is 0.168 eV and decrease with doping to 0.138 and 0.131 eV for the sample with lower Cu2+ contents (CuO : Er2O3 molar ratios of 1:2 and 1:3, respectively).

The temperature-frequency dependences of the electrical characteristics of Li2 Fe2,5-x Mex O4 (Ме=La;Y, x=0.01; 0.03; 0.05) spinels synthesized by the «sol-gel» autocombustion technology were obtained by the method of impedance spectroscopy in the temperature range of 298-473 K. Based on their analysis, the main mechanisms of conductivity of these materials in the studied temperature range were identified: hopping and activation, which are competing. The effect of doping lithium-iron spinels with rare-earth metal impurities on these conductivity mechanisms has been investigated. It has been established that the presence of impurities in small concentrations in the synthesized samples significantly decreases their conductivity, mainly due to destruction of the hopping mechanism of electronic conductivity.

In this work, the conduction mechanism in B a x S r 2 − x CrMo O 6 (0 ≤ x ≤ 0.3) double perovskite has been investigated using different techniques, such as universal dynamic response (UDR) and modulus spectroscopy. AC impedance spectroscopy has been studied in the frequency range of 0.3 Hz–5 MHz in a wide range of temperatures. It has been found that the conduction mechanism is thermally activated and frequency-dependent. The impedance fitting response to the microstructure reveals that grain boundaries are more resistive and capacitive than grains. Analysis of the complex modulus indicates that both short- and long-range charge carrier transport is responsible for conduction with non-Debye-type response in these oxides. The permittivity analysis indicates the existence of both universalities, near constant loss and UDR. Furthermore, from the Almond West power law, hopping frequency (ω c) and activation energy E a c have been calculated. The relaxation time and DC conductivity are found to obey Barton Nakajima and Namikawa's relation. In addition, the Kramers–Kronig relation and conductivity scaling are discussed to validate the impedance data and provide insight into the conduction processes in this mixed ionic electronic conductor. [ABSTRACT FROM AUTHOR]

The glass of composition 60Bi 2 O 3 –10SrO–30Fe 2 O 3 (BSFO) (in mol%) was prepared by conventional melt quenching technique. Heat treatment process was applied to the glass samples at temperature close to crystallization temperature (600 °C) for different time intervals of 0, 2, 4 and 8, respectively, to obtain glass ceramic nano-composites. X-ray diffraction (XRD) patterns displayed the formation of a cubic Bi 3.43 Fe 0.57 O 6 for BSFO glass-ceramic nano-composites. The average nanocrystallite size (D) was determined to be between 13.48 and 17.26 nm. The values of D of the present samples were increased with an increment of heat treatment time. The high resolution-transmission electron microscope (HRTEM) images of a BSFO glass sample that was heat treated at 600 °C for 4 h show the nanocrystallites dispersed in the glass matrix with particle size in the range of 17 nm. The real part of permittivity (ε′) of BSFO decreased sharply with the increment in frequency for all samples. The decrement in the magnitude of the real part of impedance (Z′) with the increment in both frequency and temperature suggests an increase in ac conductivity σ ac. The correlated barrier hopping (CBH) model can explain the exponent S and temperature behavior we observed throughout all samples. For all glass–ceramic nano-composites, with an increase in the electric field, remnant polarization P r increases. This confirms its ferroelectric nature. The energy storage density (W r) is found to be maximum for the HT 8 h sample and equal to 34.3 mJ/cm3. The efficiency (η) of the HT 8 h sample was 65 %. The (M − H) loops of the glass–ceramic nano-composites displayed an antiferromagnetic trend. These observations suggest that the present samples might be a promising option for producing energy storage devices. [ABSTRACT FROM AUTHOR]

The ceramic samples of Y 1-x Ca x Fe 0.5 Co 0 · 5 O 3 (x = 0.15, 0.25, 0.35) has been synthesized using solid-state reaction method. These samples exhibited orthorhombic perovskite structure and belonged to the Pbnm space group. X-ray analysis confirmed that Ca2+ ions replaced Y3+ ions at the A-site of perovskite structured YFe 0 · 5 Co 0 · 5 O 3 compound, while XPS studies confirmed the oxidation states of the constituent atoms. SEM micrographs and Williamson-Hall analysis showed that the crystallite size reduces with increasing Ca content, resulting in a strain-free, accommodated and stable microstructure. Complex impedance spectroscopic investigations established that the dispersion behaviors exhibited by the samples are due to Interfacial and Bulk polarizations. These phenomena are attributed to the accumulation of space charges and the hopping of electrons, respectively. Study further explore the semiconducting nature and negative temperature coefficient behavior of the material. Nyquist plots showed that grain interior is the major contributor to the conduction mechanism, while grain boundaries playing a secondary role. Correlated Barrier Hopping (CBH) has emerged as a suitable model to elucidate the conduction mechanism. The conduction process facilitated by CBH could potentially account for the observed negative permittivity in the material. [ABSTRACT FROM AUTHOR]

Ti–Ni matrix composites were produced using spark plasma sintering (SPS), a powder metallurgy technique. The influence of Ni-xTiB 2 additions on the titanium matrix microstructure, hardness, and electrochemical properties was investigated. Scanning electron microscopy, hardness analysis incorporating regression analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy tests were used to characterize the titanium matrix composites. The titanium matrix induced microstructural changes, leading to the coexistence of α and β phases along grain boundaries. A more substantial equiaxed α phase was observed in the Ti+5Ni+20TiB 2 composite. The X-ray diffraction analysis showed that the crystal structures of the composites were altered and that the grains were refined. The microhardness increased with the TiB 2 content. The potentiodynamic polarization analysis indicated that the corrosion resistance of the composites improved with the addition of Ni and TiB 2 , with the Ti+5Ni+20TiB 2 composite exhibiting the highest corrosion resistance. The electrochemical impedance spectroscopy revealed that the Ti+5Ni+20TiB 2 composite had enhanced diffusion properties and a stable passive layer, further confirming its exceptional corrosion resistance. Additionally, the composites exhibited a distinct capacitive behavior, indicative of strong corrosion resistance. This is characterized by phase angle values close to −90° and high impedance values (109 Ω cm2) at low and medium frequencies. This is due to the formation of a very stable film on the composites in the test solutions (NaCl and HCl). [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate the influence of SO42− in aerobic/anaerobic environment and its interaction with HCO3− on the corrosion behavior of Q345 carbon steel using potentiodynamic polarization, X-ray diffraction, white-light interferometer, electrochemical impedance spectroscopy and scanning electron microscopy methods. It was found that the corrosion rates of Q345 carbon steel are faster in aerobic environment under the synergistic effects of SO42− and dissolved oxygen compared to that in the absence of oxygen. In solutions containing SO42− and HCO3− in anaerobic environment, a high proportion of HCO3−/SO42− leads to the passivation of Q345 carbon steel sample as a result of the competitive adsorption of HCO3− on substrate surface with smaller radius. As the ratio of HCO3−/SO42− decreases, the presence of SO42− can enhance the dissolution of Fe matrix, thereby resulting in the corrosion of specimens. High concentration of HCO3− also exhibits the suppression on corrosion because of the formation of dense corrosion products. [ABSTRACT FROM AUTHOR]

"Anode‐free" solid‐state battery concepts are explored extensively as they promise a higher energy density with less material consumption and simple anode processing. Here, the homogeneous and uniform electrochemical deposition of alkali metal at the interface between current collector and solid electrolyte plays the central role to form a metal anode within the first cycle. While the cathodic deposition of lithium has been studied intensively, knowledge on sodium deposition is scarce. In this work, dense and uniform sodium layers of several microns thickness are deposited at the Cu|Na3.4Zr2Si2.4P0.6O12 interface with high reproducibility. At current densities of ≈1 mA∙cm−2, relatively uniform coverage is achieved underneath the current collector, as shown by electrochemical impedance spectroscopy and 3D confocal microscopy. In contrast, only slight variations of the coverage are observed at different stack pressures. Early stages of the sodium metal growth are analyzed by in situ transmission electron microscopy revealing oriented growth of sodium. The results demonstrate that reservoir‐free ("anode‐free") sodium‐based batteries are feasible and may stimulate further research efforts in sodium‐based solid‐state batteries. [ABSTRACT FROM AUTHOR]

Diesel is consistently a very popular fuel for internal combustion engines. Its consumption in the European Union has been rising over recent years, as has the number of engines increasingly sensitive to fuel contamination. One of the most important parameters affecting diesel quality is water content. Its exceedance of the standard's permissible amount carries the risk of serious damage to expensive, modern fuel injection systems. Current methods of measuring water content require both specialised personnel and equipment, as well as transporting the sample to a suitable laboratory. Analysing the properties of diesel is challenging, mainly because many types of the fuel are sold, the chemical composition of which is always a well-guarded manufacturer's secret. The research presented in this paper is aimed at verifying whether it is possible to test the moisture content of diesel using impedance spectroscopy. To date, it is the first such attempt with commercially available diesel using this method, which, once refined, could be used in situ. The authors propose and apply a novel technique that is able to be used when the electrical properties of tested oils are unknown. The experimental results obtained show that it is possible to use impedance spectroscopy to estimate the water content of different types of diesel fuel. The measurement accuracy achieved makes it possible to detect approaching or exceeding the permissible water content. [ABSTRACT FROM AUTHOR]

The study presents a promising approach to enzymatic kinetics using Electrochemical Impedance Spectroscopy (EIS) to assess fundamental parameters of modified enteropeptidases. Traditional methods for determining these parameters, while effective, often lack versatility and convenience, especially under varying environmental conditions. The use of EIS provides a novel approach that overcomes these limitations. The enteropeptidase underwent genetic modification through the introduction of single amino acid modifications to assess their effect on enzyme kinetics. However, according to the one-sample t-test results, the difference between the engineered enzymes and hEKL was not statistically significant by conventional criteria. The kinetic parameters were analyzed using fluorescence spectroscopy and EIS, which was found to be an effective tool for the real-time measurement of enzyme kinetics. The results obtained through EIS were not significantly different from those obtained through traditional fluorescence spectroscopy methods (p value >> 0.05). The study validates the use of EIS for measuring enzyme kinetics and provides insight into the effects of specific amino acid changes on enteropeptidase function. These findings have potential applications in biotechnology and biochemical research, suggesting a new method for rapidly assessing enzymatic activity. [ABSTRACT FROM AUTHOR]

A new construction of a potentiometric sensor was introduced for the first time. It relies on the use of two membranes instead of one, as in the well-known coated-disc electrode. For this purpose, a new electrode body was constructed, including not one, but two glassy carbon discs covered with an ion-selective membrane. This solution allows for the sensor properties to be enhanced without using additional materials (layers or additives) on the membrane. The new construction is particularly useful for in situ measurements in environmental samples. Two ion-selective polymeric membranes were used, namely H+ and K+-selective membranes, to confirm the universality of the idea. The tests conducted included chronopotentiometric tests, electrochemical impedance spectroscopy, and potentiometric measurements. The electrical and analytical parameters of the sensors were evaluated and compared for all tested electrodes to evaluate the properties of the planar electrode versus previously known constructions. Research has shown that the application of two membranes instead of one allows for the resistance of an electrode to be lowered and for the electrical capacitance to be elevated. Improving the electrical properties of an electrode resulted in the enhancement of its analytical properties. The pH measurement range of the planar electrode is 2–11, which is much wider in contrast to that of the single-membrane electrode. The linear range of the K+-selective planar electrode is wider than that of the coated-disc electrode and equals 10−6 to 10−1 M. The response time turned out to be a few seconds shorter, and the potential drift was smaller due to the application of an additional membrane in the electrode construction. This research creates a new opportunity to design robust potentiometric sensors, as the presented construction is universal and can be used to obtain electrodes selective to various ions. [ABSTRACT FROM AUTHOR]

Fulfilling the service life of a Lithium‐Ion battery in each intended application requires further understanding of the cells' lifetime and reliability. Derived from literature, controlling the external pressure constant on Lithium‐Ion battery cells is an inevitable factor to extend the cycle lifetime. Thus, active knowledge of the cells' strain and understanding the impact of an external pressure on the impedance is mandatory to evaluate an optimum pressure to improve the cell performance. This work presents correlations between voltage, strain, and impedance as a function of the applied constant external pressure on a nickel‐rich nickel‐mangan‐cobalt (NMC) lithium‐ion pouch cell. Utilizing a high precision universal testing machine reveals a negligible change of the cells' maximum stroke within the pressure range from 0 to 1000 kPa. Additionally, an optimum pressure between 100 and 300 kPa is revealed by analyzing a series of electrochemical impedance spectroscopy data measured at different constant external pressures. Within this pressure range the charge transfer resistance as well as the diffusive processes exhibit its optimum. [ABSTRACT FROM AUTHOR]

In the present study, we have demonstrated the synthesis of zirconia (ZrO2) and polythiophene (PTh)-based nanocomposite (ZrO2/PTh) for supercapacitors (SCs). The synthetic method was found to be efficient and low-cost. The ZrO2/PTh was characterised using different analytical techniques. The electrochemical investigations have been conducted using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy, respectively. The maximum specific capacitance of ZrO2/PTh was found to be 341.3 F/g under a three-electrode system. Cyclic stabilities of ZrO2/PTh have been evaluated to be 88.6% and 81.7% after 5000 cycles under three and two electrode systems, respectively. The power densities of ZrO2/PTh were found to be 1830.4, 1659.6, 1000.8, 750, 667.2, and 333.3 W/kg at energy densities of 0.3, 0.4, 0.6, 0.7, 1.2, and 1.9 Wh/kg, respectively. [ABSTRACT FROM AUTHOR]

A pair of polyaniline (PANIs) samples was prepared from HCl or H2SO4 electrolytes containing 0.01 M of aniline, and then subjecting them to electropolymerization. The morphology, structure, and properties of the samples were characterized using scanning electron microscope, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The results demonstrate that the capacitance and morphology of the product depend exclusively on the reactive medium used. The PANI was used as a material electrode in a supercapacitor, and the electrochemical performance of the elaborated electrodes was evaluated using cyclic voltammetry, galvanostatic charge/discharge measurement, and electrochemical impedance spectroscopy. The optimal results for the specific capacitance of the PANI films were achieved under a 5-mVs−1 scan rate, ranging from 410.35 F/g for the FTO/PANI-H2SO4 to 758.72 F/g for the FTO/PANI-HCl. [ABSTRACT FROM AUTHOR]

The chemically synthesized poly (aniline-co-o-aminobenzoic acid) copolymer was functionalized electrochemically by cationic and anionic doping and tailored its property for suitable redox behavior. The mechanism during this process has been proposed using cyclic voltammetry studies, and the doping was confirmed in FTIR and UV studies. In the electrochemical impedance spectroscopy, undoped and doped behavior revealed the possibility of fine-tuning of conditions that are required for redox supercapacitor. A symmetrical supercapacitor was fabricated with an optimized doped co-polymer-based electrode and the specific capacitance values were 107 Fg−1 for n-doped polymer and 140 Fg−1 for p-doped polymer. The electrochemical characterization of n/p 1 cm2 cells in terms of specific power, specific energy, specific capacitance, columbic efficiency, IR drop, and ESR was calculated from charge/discharge studies. Data were analyzed in terms of complex power versus complex capacitance, and hence, active region of n/p supercapacitor was obtained. This concept paves way for future tailoring of dopants during the synthesis of conducting polymer and its copolymers. [ABSTRACT FROM AUTHOR]

Here, we investigate the effect of high-pressure torsion (HPT), a severe plastic deformation process, on the mechanical properties, corrosion, and cytotoxicity of Mg–6Zn–0.2Ce alloy, a candidate material for bioresorbable bone implants. This alloy was processed by quasi-constrained HPT by applying a pressure of 6 GPa at room temperature for 1, 2, and 5 turns. Samples processed to two turns of HPT showed the smallest grain size, the highest strength that was approximately five times higher than the as-received coarse-grained sample and a reduction in the ductility. Electrochemical impedance spectroscopy and potentiodynamic polarization demonstrated the highest corrosion resistance for the Mg-alloy processed for two turns of HPT; however, accelerated degradation due to pitting corrosion was observed after immersion in simulated body fluid for 3 days. Nevertheless, all HPT-processed samples showed lower corrosion rates in all corrosion tests compared to their annealed counterparts. Finally, cell culture revealed good cytocompatibility without any noticeable changes in cytotoxicity following HPT processing. Overall, HPT for two turns showed enhanced strength and reduced corrosion rates without loss in cytocompatibility for the Mg–6Zn–0.2Ce alloy, making it a promising strategy to enhance the performance of the alloy as a bioresorbable orthopedic biomaterial. This work highlights the potential of HPT as a viable technique to improve the biomedical performance of Mg alloys for engineering next-generation biomedical implants. [ABSTRACT FROM AUTHOR]

Voltammetric analysis of Levofloxacin (LF) using an electrochemically polymerized composite of DL‐phenylalanine (DLP) alongside a bare carbon paste electrode. The constructed electrodes are polymerized DL‐phenylalanine modified carbon paste electrodes P(DLP/MCPE) and bare carbon paste electrodes (BCPE). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and other electrochemical techniques used for characterization of P(DLP/MCPE) and BCPE in 0.2 M phosphate buffer solution (PBS) with pH 4.5 were conformed using the P(DLP/MCPE), and it shows the highest current responses compared to the BCPE. This research work examines the effect of pH in PBS, scan rate, and LF concentration on the surface of P(DLP/MCPE). The outcome result shows that the oxidation reaction of LF pH is an adsorption‐controlled path. The detection limit of LF ranges from 0.2 μM to 7.0 μM, and the lower limits of detection (LOD) is 0.613x10−7 M and the lower limits of quantification (LOQ) is 2.051X10−7 M. The electrochemical P(DLP/MCPE) shows good repeatability, reproducibility, and stability. Finally, by analyzing LF in a pharmacological sample, the real time application of the sensor was assessed, and significant recoveries were observed. [ABSTRACT FROM AUTHOR]

As a sustainable valorization route, electrochemical glycerol oxidation reaction (GOR) involves in formation of key OH* and selective adsorption/cleavage of C−C(O) intermediates with multi‐step electron transfer, thus suffering from high potential and poor formate selectivity for most non‐noble‐metal‐based electrocatalysts. So, it remains challenging to understand the structure–property relationship as well as construct synergistic sites to realize high‐activity and high‐selectivity GOR. Herein, we successfully achieve dual‐high performance with low potentials and superior formate selectivity for GOR by forming synergistic Lewis and Brønsted acid sites in Ni‐alloyed Co‐based spinel. The optimized NiCo oxide solid‐acid electrocatalyst exhibits low reaction potential (1.219 V@10 mA/cm2) and high formate selectivity (94.0 %) toward GOR. In situ electrochemical impedance spectroscopy and pH‐dependence measurements show that the Lewis acid centers could accelerate OH* production, while the Brønsted acid centers are proved to facilitate high‐selectivity formation of formate. Theoretical calculations reveal that NiCo alloyed oxide shows appropriate d‐band center, thus balancing adsorption/desorption of C−O intermediates. This study provides new insights into rationally designing solid‐acid electrocatalysts for biomass electro‐upcycling. [ABSTRACT FROM AUTHOR]

The use of conductive polymers in aluminium electrolytic capacitors prevents leakage and enlarges the temperature use range when compared with their liquid counterparts. PEDOT:PSS is an outstanding candidate due to its tunable properties, i.e., electronic conductivity (10−5 to 103 S/cm), and its high thermal stability. As a result of their synthesis, PEDOT:PSS dispersions are characterized by a low pH value, which can influence pH sensitive materials such as aluminium. However, no work to date has studied the interaction between PEDOT:PSS dispersions and aluminium oxide substrates. In this work, the interface and interaction between PEDOT:PSS and an aluminium electrode were studied for the first time via odd random phase electrochemical impedance spectroscopy and analysed post mortem by SEM and AFM characterization. PEDOT:PSS dispersions at different pH values (1.9, 4.9, 5.8) were applied in a layered manner onto a non-etched aluminium substrate with a grown oxide layer on top, which provided a model system for the analysis of the interface. The analysis showed that the acidic PEDOT:PSS dispersions attacked the aluminium substrate, forming pores on the surface, but had a positive impact on the capacitance of the aluminium oxide/PEDOT:PSS systems. On the other hand, neutral dispersions did not affect the aluminium electrode, but showed poor layer formation properties, and the electrochemical analysis displayed a dispersion of results ranging from capacitive to resistive behaviour. [ABSTRACT FROM AUTHOR]

The paper investigates electrical properties of fully stabilized zirconia, which is widely applied as a solid electrolyte in electrochemical devices such as solid oxide fuel cells. High ionic conductivity of these materials is crucial for effective operating of the devices; however, grain boundary resistivity limits conductivity in polycrystalline ceramics. Thus, optimisation of the microstructure of zirconia is necessary from an application point of view. Based on three-dimensional electron backscatter diffraction (3D EBSD) data, the research employed a complex impedance spectroscopy to establish a correlation between microstructure of cubic zirconia sinters and their conductivity. Samples with different levels of anisotropy in grain boundary plane parameters were investigated. The obtained results indicate that the conduction of ions through the grain boundaries is higher in the sample with the higher representation of the near-(001) grain boundaries. Such a relationship suggests that an over-representation of low-energy grain boundaries in zirconia polycrystals leads to an increase of ionic conductivity. [ABSTRACT FROM AUTHOR]

In transportation and operation, lithium-ion batteries can be exposed to environments where the temperature exceeds 75 °C, compromising seal integrity and leading to electrolyte leakage and safety issues. Standards introduced by regulatory bodies require temperature testing, including temperature cycling tests. This study examines cylindrical battery electrolyte leakage due to temperature cycling between 25 °C and 80 °C through capacity tests, electrochemical impedance spectroscopy, computed tomography scans, and thermal analysis. Different thermal expansions among battery cap elements were identified as the cause of leakage. The thermal test parameters and requirements in the UN Manual of Tests and Criteria Section 38.3 were reviewed, revealing the 72 °C upper-temperature limit and the 24 h storage period after temperature cycling fail to effectively qualify lithium-ion batteries for real-world applications. [ABSTRACT FROM AUTHOR]

Electrical impedance spectroscopy (EIS) has been proposed as a promising noninvasive method to differentiate healthy thyroid from parathyroid tissues during thyroidectomy. However, previously reported similarities in the in vivo measured spectra of these tissues during a pilot study suggest that this separation may not be straightforward. We utilise computational modelling as a method to elucidate the distinguishing characteristics in the EIS signal and explore the features of the tissue that contribute to the observed electrical behaviour. Firstly, multiscale finite element models (or 'virtual tissue constructs') of thyroid and parathyroid tissues were developed and verified against in vivo tissue measurements. A global sensitivity analysis was performed to investigate the impact of physiological micro-, meso- and macroscale tissue morphological features of both tissue types on the computed macroscale EIS spectra and explore the separability of the two tissue types. Our results suggest that the presence of a surface fascia layer could obstruct tissue differentiation, but an analysis of the separability of simulated spectra without the surface fascia layer suggests that differentiation of the two tissue types should be possible if this layer is completely removed by the surgeon. Comprehensive in vivo measurements are required to fully determine the potential for EIS as a method in distinguishing between thyroid and parathyroid tissues. [ABSTRACT FROM AUTHOR]

In this work, the graphite nanopowder (GNP) reinforced poly(vinyl alcohol) based Bismuth ferrite (BiFeO3; BFO) composite films with different weight percentages of GNP using a solution casting technique. The electrical properties of GNP‐reinforced PVA composites are investigated using a complex impedance spectroscopy (CIS) technique to show the bulk and grain effect with the rise in frequency by an impedance analyzer in a frequency range from 102 to 106 Hz at room temperature. The single semicircle is showing in the complex planes using the real and imaginary impedance characteristics. The GNP‐reinforced PVA composite films show evidence of bulk and grain impact in complicated impedance analysis. Based on the Nyquist plot, it appeared that only the bulk effects of the resultant composite systems are present. [ABSTRACT FROM AUTHOR]

We reported a highly efficient electrochemical immunosensor utilizing chitosan–graphene nanosheets (CS-GNs) nanocomposites for the detection of aflatoxin B1 (AFB1) in corn samples. The CS-GNs nanocomposites, serving as a modifying layer, provide a significant specific surface area and biocompatibility, thereby enhancing both the electron transfer rate and the efficiency of antibody immobilization. The electrochemical characterization was conducted utilizing both differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Moreover, the antibody concentration, pH, antibody immobilization time, and immunoreaction time, were optimized. The results showed that the current change ( Δ I ) before and after the immunoreaction demonstrated a strong linear relationship ( R 2 = 0.990 ) with the AFB1 concentration, as well as good specificity and stability. The linear range extended from 0.05 to 25 ng/mL, with a detection limit of 0.021 ng/mL ( S / N = 3 ). The immunosensor exhibited a recovery rate ranging from 97.3% to 101.4% in corn samples, showing a promising performance using an efficient method, and indicating a remarkable prospect for the detection of fungal toxins in grains. [ABSTRACT FROM AUTHOR]

Bi(2/3)‐xSmxCu3Ti4O12 (BSCTO x = 0.05, 0.10, and 0.20) ceramics are synthesized using semi‐wet technique and an extensive investigation into their structural, morphological, and elemental properties, alongside dielectric and impedance behaviors, is meticulously carried out. X‐ray powder diffraction analysis unequivocally confirmed the formation of a monophasic BCTO cubic phase without any discernible secondary phases. and the crystallite size of the BSCTO ceramic, obtained by X‐ray diffraction using Debye Scherrer formula, range from 62 to 81 nm. Rietveld analysis reveals that ceramics have a body centered cubic structure with space group Im‐3. The Scanning electron microscope image displays the dense microstructure of the ceramics, while EDX analysis unveils the elemental composition of resulting products. Doping with Sm3+ induced a notable reduction in grain size, as observed through Scanning electron microscope and Atomic Force Microscope analyses, indicating Sm3+ hindered grain growth during sintering, potentially resulting in reduced dielectric constant (ε′). Dielectric constant and dielectric loss of the composition (x = 0.2) are found to be ≈$ \approx $152 and 0.04, respectively at room temperature (1 kHz). Impedance characteristics revealed a substantial increase in grain boundary resistance, leading to improved dielectric loss. The AC conductivity of BSCTO ceramics exhibited a frequency‐dependent increase satisfying to Johncher's power law. [ABSTRACT FROM AUTHOR]

Objective: Breast cancer related lymphedema (BCRL) may be assessed through objective measurement of limb swelling with common techniques including volumetric measurement using a tape measure or perometry, and measurement of extracellular water using bioimpedance spectroscopy (BIS). This study aimed to evaluate the performance of a stand-on BIS device for detection of BCRL, introduce a novel graphical method to compare volumetric and BIS methods alongside traditional specificity and sensitivity analysis, and determine and compare BIS thresholds with those published previously. Materials and Methods: Female participants with indocyanine green lymphography confirmed unilateral arm lymphedema (n = 197) and healthy controls (n = 267) were assessed using a cross-sectional study design. BIS and volumetric measures were obtained in a single session. Results: The BIS lymphedema index (L-Dex) method had a significantly higher sensitivity than the excess volume approach (area under the curve = 0.832 vs. 0.649, p = 0.0001). A threshold of L-Dex 6.5 had a higher true positive rate (70.6%) than L-Dex 10 (68.5%) although false positive rate increased from 0.4% to 2.6%. A threshold of 5% excess volume improved the true positive rate (68.5%) compared with 10% excess volume (49.7%) however the false positive rate increased to an unacceptable 47%. The L-Dex ranges in this study were not significantly different from previously published ranges. Conclusion: BIS was superior for identifying BCRL compared with volume measurements, reaffirming the value of this technique. However, it is recommended that BIS be used in conjunction with comprehensive evaluation of symptoms and clinical presentation. The proposed graphical method provides a simple and easily interpretable approach to compare and define concordance between the two commonly used methods for BCRL assessment namely limb volume and BIS L-Dex indices. The existing BIS (L-Dex) thresholds for presence of BCRL were also validated. [ABSTRACT FROM AUTHOR]

It is thought that esophageal hypersensitivity in combination with an impaired mucosal barrier function contributes to PPI-resistant reflux symptoms. Ziverel, a bioadhesive agent that coats the esophageal wall, was shown to have a positive effect on reflux symptoms. However, the mechanisms of action are unclear. We aimed to assess the effect of Ziverel on esophageal sensitivity to acid and mucosal barrier function. We performed a double-blind randomized placebo-controlled crossover trial in PPI-refractory patients with reflux symptoms. Patients were assigned (1:1) to 14 days of Ziverel followed by 14 days of placebo or opposite treatment order. The effect was evaluated using acid perfusion tests, an upper endoscopy with electrical tissue impedance spectroscopy (ETIS) and esophageal biopsies. The primary outcome was the esophageal sensitivity based on perfusion sensitivity score. Secondary outcomes included mucosal barrier function and reflux symptoms and correlations between the different outcomes. Perfusion sensitivity score was not significantly different during treatment with Ziverel (106 (73–115)) and placebo (102 (67–110)) (p = 0.508) along with total RDQ score (2.6 (1.9–3.3) vs 2.8 (1.6–3.5) p = 0.456). ETIS showed comparable values during treatment with Ziverel (13514 (8846–19734)Ω·m) and placebo (13217 (9127–24942)Ω·m (p = 0.650)). Comparing Ziverel and placebo no difference was seen in transepithelial electrical resistance (TEER) 203 (163–267) Ω.cm2 vs 205 (176–240) Ω.cm2 (p = 0.445) and fluorescein flux 775 (17–6964) nmol/cm2/h vs 187 (4–12209) nmol/cm2/h (p = 0.638). Ziverel did not show a benefit on acid sensitivity, reflux symptoms or esophageal mucosal integrity compared to placebo in PPI-refractory patients with reflux symptoms. Trial registration: Netherlands Trial Register number: NL7670 [ABSTRACT FROM AUTHOR]

The rapid fabrication is described of binary electrocatalyst based on a highly porous metal–organic framework with zirconium metal core (Zr-MOF) decorated over the graphitic carbon nitride (g-C3N4) nanosheets via facile ultrasonication method. It is used for the robust determination of antipsychotic drug chlorpromazine (CLP) from environmental samples. The electrochemical behaviour of 2D Zr-MOF@g-C3N4 was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies. The crystalline and porous nature of the composite was characterized by XRD and SEM analysis. The functional groups and surface characteristics were investigated by FT-IR, Raman and XPS. The major electrochemical properties of the Zr-MOF@g-C3N4 composite towards CLP detection were analyzed by CV, chronocoulometric (CC), chronoamperometric (CA) and differential pulse voltammetry (DPV) techniques. The composite exhibits a low detection limit (LOD) of 2.45 nM with a linear range of 0.02 to 2.99 µM and attractive sensitivity for CLP. The sensor system shows higher selectivity towards the possible interferences of CLP drug and exhibits better repeatability and stability. Finally, the fabricated sensor system shows a high recovery range varying from 96.2 to 98.9% towards the real samples. The proposed electrochemical probe might be a promising alternative to the prevailing diagnostic tools for the detection of CLP. [ABSTRACT FROM AUTHOR]

The current work reports the synthesis of magnesium aluminate spinel (MgAl2O4) using wet-chemical sol-gel technique at two different sintering temperatures of 900 °C and 1100 °C. The crystal structure of MgAl2O4 at both sintering temperatures was confirmed by X-ray diffraction. The obtained results showed the successful formation of MgAl2O4 along with some impurity peaks of magnesium oxide. Here, the crystallite size shows the linear nature with sintering temperature. The field emission scanning electron microscope (FESEM) shows the spherical shape. The change in morphology with sintering temperature is also confirmed by FESEM. Optical and electronic responses were studied by Fluorescence (FL) and electrochemical impedance spectroscopy (EIS). The FL study reveals that the prepared nanopowder tends to emit white light under the excitation wavelength of 350 nm. The intensity of emission peaks has been found to increase with sintering temperature, indicating an increase in defect states. Furthermore, using EIS data, the electrical parameters were studied in pellet form in the frequency range of 1 to 106 Hz. The Nyquist plots have been successfully explained by employing LR[Q[R(CR)]] equivalent circuit corresponding to grain, grain boundary, and electrode contribution. The examined parameters have been significantly influenced by the sintering temperature. An increase in temperature is observed to result in higher values for the dielectric constant, loss tangent, and conductivity. Additionally, the electric modulus spectra reveal non-Debye behavior in the samples. The obtained results reveal that the prepared nanopowder can be used in optoelectronic devices, high-frequency equipment, and high-storage media. [ABSTRACT FROM AUTHOR]

Identifying and quantifying accessible nutrients in the soil are critical in agriculture since plants require particular amounts of micro and macronutrients to grow successfully. However, there is no well-defined method for quantifying macronutrients in the field at present. In this work, chitosan and chitosan-molybdate membranes were deposited onto stainless steel (SS) and carbon (C) substrates and evaluated as promising candidates for the quantification of phosphorous species available in cultivated soil. The membranes were morphologically and structurally studied by atomic force microscopy and infrared spectroscopy to determine their appearance, roughness, and chemical conformation. Electrochemical impedance spectroscopy was the electrochemical tool used to evaluate the quantification capacity of phosphorus species of the membrane-based electrodes; it was found that the chitosan-molybdate membranes deposited onto the SS/C interface presented the best performance when the electrodes change in charge transfer resistance and chemical capacitance were measured as a function of the concentration of phosphorus species available in a synthetic sample. Thus, based on the presented results, chitosan biosensors have shown the capability of attracting ionic species, which contributes to the minimization of preference zones on the surface of a sensing electrode. [ABSTRACT FROM AUTHOR]

A heterojunction photocatalytic material Cu31S16/Cu9S5 was successfully synthesized through a facile solvothermal method by controlling the reaction temperature. The phase composition, morphology, absorbance and surface area were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffusion reflection and Brunauer–Emmett–Teller (BET). Transient photocurrent response and electrochemical impedance spectroscopy (EIS) were measured to support the generation and transfer of the photoinduced charge carriers. The heterojunction Cu31S16/Cu9S5 showed superior separation efficiency of the photoinduced charge carriers. The photocatalytic performance of the Cu31S16/Cu9S5 was evaluated through degrading high-concentration methyl orange (MO) solution under visible light. The degradation rate of MO solution increased to 94.8% in 60 min, showing the most remarkable photocatalytic ability. Moreover, a probable photocatalytic mechanism of the Cu31S16/Cu9S5 was discussed. [ABSTRACT FROM AUTHOR]

Magnetic Fe 3 O 4 /α-Fe 2 O 3 heterogeneous nanorods with the saturation magnetization of 69.5 emu/g were prepared via the hydrothermal and calcination-reduction process using β-FeOOH nanorods as precursor and galactose as the reducing agent. The average length and diameter of the nanorods were 81.6 nm and 23.9 nm, respectively. The surfaces of the heterogeneous nanorods were modified with PEI and HAuCl 4 , resulting in magnetic rod-like Fe 3 O 4 /α-Fe 2 O 3 @Au nanocomposites. By utilizing the Au–S effect, Apt/ssDNA hybrid double-strands were loaded onto Fe 3 O 4 /α-Fe 2 O 3 @Au nanocomposites to form Fe 3 O 4 /α-Fe 2 O 3 @Au-Apt/ssDNA biosensors capable of recognizing mucoprotein-1 (MUC1) mucoprotein. These biosensors could be magnetically assembled onto a magnetic glassy carbon electrode to create a "Turn off" type electrochemical biosensor. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) techniques were used to evaluate the detection performance. Based on the change in DPV signals, the optimal concentrations of magnetic Fe 3 O 4 /α-Fe 2 O 3 @Au nanocomposites and Apt/ssDNA double-stranded probes were 12 mg/mL and 9 μM, respectively, while the optimal incubation time was 2 h. Under these conditions, the sensor exhibited a linear detection range of 0.1 pg/mL to 1500 pg/mL (R2 = 0.9988), with a limit of detection (LOD) of 0.1 pM and a limit of quantitation (LOQ) of 0.34 pM. The biosensor demonstrated excellent performance in terms of selectivity, reproducibility (RSD = 2.9 %), and stability. When actual serum samples diluted by a factor of 20 in PBS were tested, the recovery rate ranged from 95.65 % to 103.40 %, indicating that this approach for sensitive detection of MUC1 holds promising prospects. [ABSTRACT FROM AUTHOR]

The stem extract of Solanum Lycopersicum prepared using the methanol extraction method has been investigated as an environment-friendly inhibitor for low-carbon steel in monoprotic(1N HCl) and diprotic(1N H2SO4) solvents and characterized with FT-IR. A maximal inhibition efficiency of 81.8% in 1 N Hydrochloric acid and 92.92% in 1 N Sulfuric acid is assessed under a certain set of conditions of inhibitor concentration and temperature using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization. The results present Solanum Lycopersicum extract as a mixed-type inhibitor that predominantly influences the cathodic reaction and followed the Langmuir adsorption isotherm. Reduction in the value of average roughness (Ra)of the surface from 217 nm to 55 nm (in 1 N HCl) and 139.6 nm to 28 nm (in 1 N H2SO4) was observed with AFM after the application of the inhibitor which confirms the formation of a protective membrane and provides green inhibition on the low-carbon steel/solution interface. [ABSTRACT FROM AUTHOR]

2R-1C equivalent circuit is widely used in electrochemical impedance spectroscopy (EIS), such as modelling of lithium-ion batteries, bioimpedance analysis and water quality monitoring. It allows for an analysis of the basic electrical behavior of electrochemical systems and understanding of the underlying principles. However, the reported parameter estimation methods are usually deployed on the PC-based processing units that limit in-situ and unsupervised applications, where estimation results are free from user inputs. This paper presents a novel methodology for extracting the values of 2R-1C equivalent circuit by solely utilizing the measured impedance modulus. Unlike iterative and PC-based estimation methods, this approach eliminates user inputs in terms of a need for an initial guess, addressing a significant drawback of those approaches. The proposed work was validated by simulated and experimentally obtained impedance. Moreover, details of deployment on the PC-based and embedded hardware were also reported. The utilization of embedded hardware platform (Mega2560) enables an efficient processing of EIS data (80 milliseconds for 100 datapoints) by creating opportunities for in-situ parameter extraction of equivalent electrical circuits. [ABSTRACT FROM AUTHOR]

Phytotoxins produced by marine microalgae, such as paralytic shellfish toxins (PSTs), can accumulate in bivalve molluscs, representing a human health concern due to the life-threatening symptoms they cause. To avoid the commercialization of contaminated bivalves, monitoring programs were established in the EU. The purpose of this work is the implementation of a PST transforming enzyme—carbamoylase—in an impedimetric test for rapid simultaneous detection of several carbamate and N-sulfocarbamoyl PSTs. Carbamoylase hydrolyses carbamate and sulfocarbamoyl toxins, which may account for up to 90% of bivalve toxicity related to PSTs. Conformational changes of carbamoylase accompanying enzymatic reactions were probed by Fourier transform mid-infrared spectroscopy (FT-MIR) and electrochemical impedance spectroscopy (EIS). Furthermore, a combination of EIS with a metal electrode and a carbamoylase-based assay was employed to harness changes in the enzyme conformation and adsorption on the electrode surface during the enzymatic reaction as an analytical signal. After optimization of the working conditions, the developed impedimetric e-tongue could quantify N-sulfocarbamoyl toxins with a detection limit of 0.1 µM. The developed e-tongue allows the detection of these toxins at concentration levels observed in bivalves with PST toxicity close to the regulatory limit. The quantification of a sum of N-sulfocarbamoyl PSTs in naturally contaminated mussel extracts using the developed impedimetric e-tongue has been demonstrated. [ABSTRACT FROM AUTHOR]

This study explores the optical and electrochemical properties of a ZnO coating layer deposited on a nanoporous alumina structure (NPAS) for potential multifunctional applications. The NPAS, synthesized through an electrochemical anodization process, displays well-defined nanochannels with a high aspect ratio (~3000). The ZnO coating, achieved via atomic layer deposition, enables the tuning of the pore diameter and porosity of the NPAS, thereby influencing both the optical and electrochemical interfacial properties. A comprehensive characterization using photoluminescence, spectroscopy ellipsometry and impedance spectroscopy (with the sample in contact with NaCl solutions) provides insights into optical and electrochemical parameters, including the refractive index, absorption coefficient, and electrolyte–ZnO/NPAS interface processes. This research demonstrates potential for tailoring the optical and interfacial properties of nanoporous structures by selecting appropriate coating materials, thus opening avenues for their utilization in various technological applications. [ABSTRACT FROM AUTHOR]

The corrosion protection property of three Brij-type surfactants, namely, Brij 35, Brij 56 and Brij 58P, was considered on OLC 45 carbon steel in a 0.5 M H2SO4 medium. The efficacy for these organic compounds was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods, scanning electron microscopy (SEM) procedures, and Fourier transform infrared (FT-IR) spectroscopy. We hypothesized that these surfactants hinder the corrosion for OLC 45 samples through a protecting mechanism owing to the adsorption of organic molecules that form an inhibitive film or through the formation of complex oxides. These surfactants exhibited an appreciable protective effect against OLC 45 corrosion, operating as mixed inhibitors, as could be demonstrated by their influence on the electrochemical characteristics of the metallic substrates. The adsorption of surfactants over the substrates zone conformed to the representation of the Langmuir isotherm. The effect of temperature on the electrochemical comportment of the OLC 45 specimens in H2SO4 without and with Brij at 800 ppm was examined in the temperature interval of 293 to 333 K. The negative estimate of thermodynamic attributed as Gibbs free energy of adsorption presented the spontaneity of the adsorption activity. The investigation with FT-IR and SEM established the adsorption of Brij and the constitution of the corrosive components on the OLC 45 surface. Electrochemical determinations of these surfactants indicated its anticorrosion inhibition performance and the highest inhibition of 96% was reached when the Brij 35 concentration was at 800 or 1000 ppm, while for Brij 56 and Brij 58P, the highest inhibition was obtained when their concentrations were 500, 800, or 1000 ppm. [ABSTRACT FROM AUTHOR]

This research is focused on enhancing the capabilities of scanning electrochemical impedance microscopy (SEIM) for detecting gold nanoparticle-labelled antibodies using electrochemically modified platinum ultramicroelectrode. The primary objective was to address the high resistance issue encountered in previous measurements with SEIM via the utilization of SEIM probes based on micro-electrodes modified by platinum microstructures, which improved the sensitivity and precision of the detection of targeted biomolecules. The modified probe resulted in a lowered charge transfer resistance by over ten times and a decrease in detection to around 100 fg/mL. We suggest potential applications in various biotechnological and biomedical fields, with future research expected to further refine this technique. [ABSTRACT FROM AUTHOR]

The direct methanol fuel cells (DMFCs) are impeded by the sluggish methanol oxidation reaction (MOR) induced by CO poisoning. In this work, we report the synthesis of PtPd alloy nanoparticles (3.2 nm) on molybdenum carbide nanosheets (PtPd@Mo 2 C). The XPS investigation indicates that Pd atoms accept electrons from Pt and Mo atoms resulting in a slight percentage of oxidized Pt capable of anchoring OH− species from water dissociation; thereby, the CO poisoned Pt is re-activated. Therefore, PtPd@Mo 2 C exhibits 8.1-fold higher mass activity than commercial PtRu/C. Ascribing to the strong electronic interaction between PtPd and Mo 2 C substrate, a superior stability is achieved for PtPd@Mo 2 C with MOR activity only decreased by 6 % after 10,000 cycles. Additionally, the operando electrochemical impedance spectroscopy measurement indicates a similar MOR kinetics to PtRu/C and a better structural stability. [Display omitted] • PdPt alloyed nanoparticles (3.2 nm) are deposited on molybdenum carbide nanosheets. • PtPd@Mo 2 C shows 8.1-fold higher mass activity toward MOR than PtRu/C. • MOR activity only decreased by 6 % is achieved for PtPd@Mo 2 C after 10,000 cycles. [ABSTRACT FROM AUTHOR]

One of the priorities in the field of hydrogen energy is the development of intermediate-temperature (IT-SOFCs) and low-temperature solid oxide fuel cells (LT-SOFCs), which are capable of highly efficient operation in the range of 500–800 °C. The currently applied 8-YSZ electrolytes are expected to be replaced by one based on tetragonal zirconia (3Y-TZP), which is characterized not only by high ionic conductivity below 700 °C, but also significantly higher mechanical strength. One of the candidates is alumina-toughened zirconia (ATZ) with extraordinary mechanical properties (flexural strength of up to 1 GPa and outstanding fracture toughness (K Ic) in excess of 10 MPa m0.5). A series of composites with a nanometric alumina content of 2.3, 10, and 20 vol% were obtained and investigated to evaluate the effects of aluminum addition on the electrical properties of the materials in relation to their microstructure, chemical and phase composition. Measurements performed by means of electrochemical impedance spectroscopy over the range of 300–650 °C showed that the total electrical conductivity of the obtained ATZ samples decreased slightly with increasing content of alumina inclusions and it was around one-third of an order of magnitude lower than that of the reference 3Y-TZP sinter prepared from the commercially available oxide powder containing 3 mol% of yttrium oxide (TOSOH). This is a consequence of the fact that ATZ sinters exhibited a lower specific conductivity of grain boundaries than 3Y-TZP whilst having comparable electrical conductivity of grain interiors. The total electrical conductivity values determined for the ATZ sinters at 700 and 800 °C are approximately the same as the electrical conductivity of 3Y-TZP, and they can therefore be considered a viable alternative to 8-YSZ electrolytes in applications such as IT-SOFCs or LT-SOFCs. [ABSTRACT FROM AUTHOR]

This study investigates a successful fabrication of MoS2/Fe3O4/PANI composite by chemical co‐precipitation method. The facile hydrothermal approach was employed to synthesize a MoS2/Fe3O4 composite, followed by the utilization of a conventional chemical oxidation strategy to produce a PANI coating on the composite, thereby generating an active material for electrochemical reactions and a structure facilitating the transportation of ions via multiple pathways. The fabricated MoS2/Fe3O4/PANI composite was characterized by SEM, ICP, XRD, FT‐IR, and so on. In this study, we delved into the electrochemical charge storage feature of MoS2/Fe3O4/PANI. The electrochemical characteristics of the nanocomposite were assessed through the implementation of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronopotentiometry techniques in a 3 M KOH electrolytic solution, utilizing nickel foam as both a material support and current collector for two electrode configurations. The findings indicate that MoS2, as the support matrix, possesses notable attributes such as a substantial surface area, elevated electrical conductivity, and varied oxidation states. As a result, the electrical conductivity performance of the MoS2/Fe3O4/PANI composite, which includes well‐dispersed Fe3O4 nano‐cubes on the surfaces of MoS2, is significantly enhanced. In comparison to pure Fe3O4, the resultant composite revealed improved specific capacitances of 401 F/g at 1.25 A g−1, along with outstanding cyclic stability of 89.3 even after undergoing 5000 cycles. The superior electrochemical properties observed may be ascribed to both the proficient electrical conductivity of MoS2 and the incorporation of Fe3O4 particles, which are anchored onto the MoS2. The results prove that MoS2/Fe3O4/PANI hybrid composite holds as highly efficient electrode material for supercapacitor. [ABSTRACT FROM AUTHOR]

Improving the separation efficiency of photo-generated electron–hole pair is a key issue in the field of photocatalytic hydrogen production. In this work, we successfully improved the efficiency of photo-generated carrier separation using the synergistic action of sulfur (S) vacancies and a Ni2P co-catalyst. Vs-Zn0.5Cd0.5S (Vs-ZCS) with S vacancies was designed and constructed, and Vs-ZCS/Ni2P photocatalysts were prepared with non-precious metal Ni2P as a co-catalyst. Among all the produced materials, Vs-ZCS/Ni2P-5% has a photocatalytic characteristic of 40.81 mmol g−1 h−1, which is 7.88, 3.08 and 3.75 times greater than those of ZCS (5.18 mmol g−1 h−1), Vs-ZCS (13.25 mmol g−1 h−1) and ZCS/Ni2P-5% (10.88 mmol g−1 h−1), respectively. The results of transient photo-current, electrochemical impedance spectroscopy, photoluminescence and time-resolved fluorescence show that the synergistic effect of S vacancies and Ni2P significantly promotes the separation and transfer efficiency of photo-generated carriers, as well as the photocatalytic hydrogen production reaction. Superoxide radicals and electrons are the active species for photocatalytic hydrogen generation, which is confirmed by active species capture tests and EPR. This study presents an innovative approach for developing photocatalysts with low cost and good catalytic performance. [ABSTRACT FROM AUTHOR]