Impedance Spectroscopy Research Articles

Lattice Distortion Creates Enhancements in Photocatalytic and Electrocapacitive Performance of Sol–Gel‐Derived Cu‐Doped NiTiO3

A remarkable 35% enhancement in the photocatalytic and electrocatalytic abilities of an ilmenite nickel titanate (NiTiO3) material is reported. This boost in catalytic performance is achieved by simply creating a static distortion in the rhombohedral unit cell by replacing a small proportion of a small‐size nondegenerate Ni (69 pm) with a large‐size degenerate Cu (73 pm). The materials are synthesized by using a simple sol–gel method. The appropriate doping amount of Cu facilitates the better separation of intrinsic charge carrier pairs by inhibiting their recombination. The photocatalytic and electrochemical activities of durable materials in aqueous MB dye (10 ppm) and KOH (1 molar) electrolyte solutions are found to be directly associated with this improvement in inherent charge carrier transfer characteristics. The enhanced photodissociation of MB dye (42–56%) and specific capacitance (381–450 F g−1) in a KOH (1 molar) electrolyte are in full accord with the investigations carried out using crystallographic and optoelectronic analysis, charging–discharging measurements, and electrochemical impedance (EIS) spectroscopy investigations. Same material with high textural surface areas or controllable particle morphologies might show a far better photo/electrocatalytic performance in a variety of practical applications.

CuO@3D graphene modified glassy carbon electrode towards the detection of Orange II and Rhodamine B

Synthetic dyes are illegally used in foodstuffs and cause serious health issues in humans due to their carcinogenic nature. To avoid serious health issues, it is compulsory to detect and remove even the minute quantities of these harmful dyes in foodstuffs. Electrochemical sensors are accredited as an efficient and promising platform for the robust and sensitive determination of food toxins in various foodstuffs. Therefore, an efficient, facile, and competent sensor is devised for the simultaneous detection of Orange II (OR II) and Rhodamine B (RhB) supported by rGO and CuO nanoparticles. The synergism between rGO’s immense surface area and the adsorption properties of CuO enhances selectivity and response time for the detection of OR II and RhB. This work elaborated the synthesis, characterization, and electrochemical behavior of CuO@3DGr electrode towards simultaneous sensing of OR II and RhB. Physicochemical techniques were utilized to validate the fabrication of targeted material. On the other hand, the electrochemical features of the developed sensor were characterized by cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). Differential pulse voltammetry technique was employed to detect simultaneously Orange II and Rhodamine B on the surface of bare (GCE), GO/GCE, CuO/GCE, and CuO@3DGr/GCE. Multi-analyte detection is possible with DPV, a sensitive electrochemical method. Based on each toxin’s specific electrochemical signature, the sensor may generate separate peaks by delivering a sequence of potential pulses and detecting the ensuing current. The parameters which influence the performance of the modified sensor were carefully evaluated. Under ambient conditions, the developed sensor exhibited excellent electrocatalytic activity in oxidation at 0.67 V of OR II and 0.96 V RhB with a low limit of detection 08 nM for OR II and 4.5 nM for RhB in Britton- Robinson buffer (BRB pH:7). The described methodology allowed a robust and fast analysis of food toxins in different foodstuff establishing this sensor as a novel tool for detecting food toxins. Tap water was used to analyze the practical applicability of developed electrode material and suitable results were achieved. These results showed that the as-synthesized novel electrochemical sensor has the potential for ultrasensitive determination and detection of toxins in different foodstuffs.

Application of Recycled Battery-Graphite Electrode Decorated with Polyglutamic Acid/Au Nanoparticles for Detection of Nalbuphine Drug Abuse

Abstract We report a highly-uniform nanocomposite of polyglutamic acid (PGA) and gold nanoparticles (AuNPs) electrodeposited on a recycled battery graphite electrode (BGE) for the detection of Nalbuphine (NB), a semi-synthetic opioid. The sensor was optimized and characterized morphologically (via scanning electron microscopy, atomic force microscopy, and energy dispersive X-ray analysis) and electrochemically (via cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy). Under optimized conditions, the PGA/AuNPs/BGE revealed two linear ranges, 2.5×10-8 to1.0×10-6 M, and 2.0 × 10-6 to 1.0 × 10-4 M for Nalbuphine (NB), that is equivalent to 9.825×10-3 to 0.393 µg/mL and 0.786 to 39.30 µg/mL, with R2 = 0.995 and 0.994, respectively, and showed good catalytic activity for the determination of nalbuphine in the presence of tramadol and the oxidation potential of these opioid analgesic drugs were separated. The sensor was successfully applied for the detection of NB in its pharmaceutical formulations, spiked urine, and human plasma samples, without applying any sample pretreatment, at a recovery range of 99±0.03 to102±0.02% and thus, the developed can be considered as a promising approach for NB abuse testing in clinical and forensic agencies.

Electrical Impedance Spectroscopy: A Tool for Determining the Harvesting Time of Olive Fruit

The harvesting time of olive (Olea europaea L.) fruit, which significantly affects the characteristics of virgin olive oil, is mainly determined empirically based on the fruit’s skin color. Developing objective methods such as electrical impedance spectroscopy (EIS) for assessing ripeness is essential. This study aimed to explore the potential of EIS as a rapid and objective technique for detecting the harvesting time of olives. Olive fruits from two varieties, ‘Picholine’ and ‘Buža momjanska’, were harvested in two periods and sorted into four color groups. EIS was applied to each color group to establish a relationship between fruit color and electrochemical properties. The distance of the coordinate at the top of the circular arc of the Cole–Cole plot from the origin (LTO) indicated tissue degradation. The LTO values varied depending on the olive variety, fruit color, and harvest date. The LTO values decreased from green to black fruits in both varieties, indicating textural changes in the olive fruit tissue. This study contributes to the knowledge and understanding of the electrical properties of olive fruit tissue during ripening. EIS shows potential as an innovative tool for determining the harvesting time of olives and for ‘in-field’ olive ripeness assessment.

Elaboration and Characterization of Electrodes from Robinia pseudoacacia and Azadirachta indica Charcoal Powder with Coconut Bio-Pitch as a Binder

Carbon-based electrodes have recently been most widely used in P-MFC due to their desirable properties such as biocompatibility, chemical stability, affordable price, corrosion resistance, and ease of regeneration. In general, carbon-based electrodes, particularly graphite, are produced using a complex process based on petroleum derivatives at very high temperatures. This study aims to produce electrodes from bio-pitch and charcoal powder as an alternative to graphite electrodes. The carbons used to manufacture the electrodes were obtained by the carbonisation of Robinia pseudoacacia and Azadirachta indica wood. These carbons were pulverised, sieved to 50 µm, and used as the raw materials for electrode manufacturing. The binder used was bio-pitch derived from coconut shells as the raw materials. The density and coking value of the bio-pitch revealed its potential as a good alternative to coal-tar pitch for electrode manufacturing. The electrodes were made by mixing 66.50% of each carbon powder and 33.50% of bio-pitch. The resulting mixture was moulded into a cylindrical tube 8 mm in diameter and 80 mm in length. The raw electrodes obtained were subjected to heat treatment at 800 °C or 1000 °C in an inert medium. The electrical resistivity obtained by the four-point method showed that N1000 has an electrical resistivity at least five times lower than all the electrodes developed and two times higher than that of G. Fourier-transform infrared spectroscopy (FTIR) was used to determine the compositional features of the samples and their surface roughness was characterised by atomic force microscopy (AFM). Charge transfer was determined by electrical impedance spectroscopy (EIS). The FTIR of the electrodes showed that N1000 has a spectrum that is more similar to that of G compared to the others. The EIS showed the high ionic mobility of the ions and therefore that N1000 has a higher charge transfer compared to G and the others. AFM analysis revealed that N1000 had the highest surface roughness in this study.

Electrochemical synthesis, physical properties and corrosion behavior of electropolymerized polyaniline films developed on 316L stainless steel

AbstractPolyaniline (PANI) films may be developed on metallic substrates by a variety of electrochemical techniques. In the present work, PANI films were electrodeposited on AISI 316L stainless steel substrates by cyclic voltammetry (CV), chronoamperometry (CA), and chronopotentiometry (CP) with the objective of comparing the efficacy of each method, based on the integrity of the developed films. Cyclic voltammetry and anodic polarization were used to determine optimal electrodeposition parameters for the development PANI films using the CA and CP methods. The structure and morphology of the coatings were characterized by scanning electron microscopy, energy‐dispersive x‐ray spectroscopy, Fourier‐transform infrared spectroscopy, and ultraviolet–visible spectroscopy. Among the evaluated techniques, CV led to the formation PANI films with the best homogeneity as well as the lowest number of defects, such as cracks or pores. Subsequently, the corrosion resistance of AISI 316L steels with and without PANI was compared in a physiological saline solution (0.9% NaCl). Potentiodynamic polarization tests indicated that the PANI‐coated samples exhibited lower corrosion current density values (0.012 vs. 0.018 μA/cm2) and lower passive current density values (0.04 vs. 0.06 μA/cm2) in comparison to the bare AISI 316L steel. Additionally, long‐term monitoring by electrochemical impedance spectroscopy revealed that PANI films consistently exhibited superior polarization resistance up to 32 days of exposure in the 0.9%NaCl solution (233,000 vs. 207,000 Ωcm2).

Impedance Spectroscopy for Bacterial Cell Monitoring, Analysis, and Antibiotic Susceptibility Testing.

Conventional approaches for bacterial cell analysis are hindered by lengthy processing times and tedious protocols that rely on gene amplification and cell culture. Impedance spectroscopy has emerged as a promising tool for efficient real-time bacterial monitoring, owing to its simple, label-free nature and cost-effectiveness. However, its limited practical applications in real-world scenarios pose a significant challenge. In this review, we provide a comprehensive study of impedance spectroscopy and its practical utilization in bacterial system measurements. We begin by outlining the fundamentals of impedance theory and modeling, specific to bacterial systems. We then offer insights into various strategies for bacterial cell detection and discuss the role of impedance spectroscopy in antimicrobial susceptibility testing (AST) and single-cell analysis. Additionally, we explore key aspects of impedance system design, including the influence of electrodes, media, and cell enrichment techniques on the sensitivity, specificity, detection speed, concentration accuracy, and cost-effectiveness of current impedance biosensors. By combining different biosensor design parameters, impedance theory, and detection principles, we propose that impedance applications can be expanded to point-of-care diagnostics, enhancing their practical utility. This Perspective focuses exclusively on ideally polarizable (fully capacitive) electrodes, excluding any consideration of charge transfer resulting from Faradaic reactions.

Giant permittivity and humidity sensitivity of SrTiO3 based ceramics induced by K, Nb donor-acceptor co-doping

This research utilizes a solid-state sintering process to fabricate a series of Sr1-xKxTi1-xNbxO3 (x =0.01, 0.02, 0.025, 0.03) ceramics. The sample with a doping concentration of x=0.025 achieved a dielectric constant of 10409 and a dielectric loss of 0.026 at 1 kHz. With increased dopant concentrations of K and Nb, the thermal stability of the ceramics is significantly enhanced, as evidenced by a dielectric constant variation of less than 15 % for x=0.025 sample over a temperature range from room temperature to 240 °C. Employing activation energy analysis, impedance spectroscopy, humidity response assessments, and X-ray photoelectron spectroscopy, it is indicated that the excellent electrical performance is attributed to the combined effects of the Internal Barrier Layer Capacitance and the formation of complex defect dipoles. Moreover, the insights into the moisture characteristics of SrTiO3 presented in this paper imply that the giant dielectric Sr1-xKxTi1-xNbxO3 ceramics have potential in the application of humidity sensing devices.

Evaluation of Different Electrolytic Solution Composition on the Microstructure and Corrosion Study on AZ31 Magnesium Alloy Using PEO Method

Abstract Magnesium (Mg) and its alloys are widely used in orthopedic implants due to their mechanical compatibility with bone tissue. However, their susceptibility to corrosion can compromise mechanical strength over time. The present study aims to enhance the corrosion resistance of AZ31 Mg alloy through Plasma Electrolytic Oxidation (PEO) coatings incorporating Hydroxyapatite (HAP). The effects of 5g of HAP in different electrolytic solutions—Sodium Silicate (Na2SiO39H2O) + Potassium Hydroxide (KOH) and Sodium Phosphate (Na₃PO₄) + Triethanolamine (C6H15NO3)—on the microstructure and corrosion characteristics were evaluated. The phase composition was analyzed using X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS), while the surface morphology and cross-section of the coatings were assessed using Field Emission Scanning Electron Microscopy (FESEM). Corrosion studies were performed using Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) under Simulated Body Fluid (SBF) conditions. The results showed that the sample with the solution containing 5 g of HAP + Na₃PO₄ + C₆H₁₅NO₃ (PS-2) exhibited superior anti-corrosion properties compared to the sample with 5 g of HAP + Na₂SiO₃·9H₂O + KOH (PS-1). Notably, the cross-sectional analysis revealed significantly smaller pores in the PS-2 coatings. Among the two coated samples, the highest polarization resistance of 3.06 × 10⁶ Ω·cm² was observed for PS-1, while PS-2 showed a lower resistance of 2.9 × 10⁶ Ω·cm², correlating with their morphological characteristics. These findings suggest that sodium phosphate and triethanolamine improve biocompatibility when combined with pure AZ31 Mg alloy and HAP coatings.

Affinity peptide-based electrochemical biosensor with 2D-2D nanoarchitecture of nickel–chromium-layered double hydroxide and graphene oxide nanosheets for chirality detection of symmetric dimethylarginine

The accurate assessment of kidney dysfunction is crucial in clinical practice, necessitating the exploration of reliable biomarkers. However, current methods for measuring SDMA often fall short in terms of sensitivity and specificity. In this study, we employed phage display technology to identify high affinity peptides that specifically bind to SDMA. The selected peptide was subsequently integrated into a novel Ni-Cr layered double hydroxide-graphene oxide (NCL-GO) nanoarchitecture. We characterized the electrochemical properties of the biosensor using cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry, systematically evaluating critical parameters such as limit of detection (LOD), reproducibility, and performance in complex biological matrices including urine. The NCL-GO architecture not only enhances the surface area available for electrochemical reactions but also facilitates rapid electron transfer kinetics which are essential for the accurate quantification of small molecule, SDMA. The electrochemical biosensor exhibited an outstanding limit of detection of 0.1 ng/mL in the 0–1 ng/mL range and 7.2 ng/mL in the 1–100 ng/mL range, demonstrating exceptional sensitivity and specificity for SDMA. Furthermore, the biosensor displayed excellent reproducibility with a relative standard deviation of 4.9%. Notably, it maintained robust chirality sensing capabilities, even in complex biological fluids. These findings suggest that this biosensor could play a pivotal role in early disease diagnosis and therapeutic monitoring, ultimately improving clinical outcomes and advancing biomedical research.

Effect of Various Carbon Coating Techniques on the Electrochemical Performance of Li4Ti5O12 Synthesized by Sol-Gel Method

This study aimed to prepare spinel carbon-coated Li4Ti5O12 (LTO/C) via sol-gel reaction and applied as a high-performance lithium-ion battery anode. The LTO powder was coated using various carbon sources, super P (SP), sugar and PVDF-assisted SP. The crystal structure, morphology, conductivity and electrochemical performance of the samples were examined using X-ray diffraction (XRD), Field Emission scanning electron microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry/Charge-discharge (CV/CD), respectively. The XRD analysis results showed that the samples contain highly crystalline spinel LTO as the main phase and rutile as impurity. The FESEM image showed that SP covers the entire LTO surface more homogenous than sugar. However, sugar carbon makes roughness on the LTO surface. FTIR spectra showed that the coating using sugar and PVDF still contain hydrocarbon element. Electrochemical performance evaluations showed that SP carbon-coated-LTO possesses higher lithium diffusion and specific capacity than pure LTO, while sugar-coated-LTO shows the lowest specific capacity. Moreover, the SP carbon-coated-LTO sample high-rate capability has improved during full cell evaluation, delivering a discharge capacity of 249, 231, 211, 194, 58, and 23 mAhg-1 at the charge or discharge current density of 0.05, 0.1, 0.5, 1, 5, and 10 C, respectively.

Operation of Amorphous TiO2-Protected Photocathodes Described with the Maxwell Equivalent Circuit.

The use of amorphous TiO2 (a-TiO2), deposited by atomic layer deposition, is a common strategy to protect semiconductors from degradation when used in water-splitting photoelectrochemical (PEC) cells. Electrochemical impedance spectroscopy (EIS) is a suitable technique to study these PEC cells because it is capable of deconvoluting multiple processes occurring during operation, therefore providing information about mechanisms leading to the overall device performance. When biased under hydrogen evolution conditions, EIS shows that two simultaneous processes occur in a-TiO2-protected photocathodes, which introduces an ambiguity in choosing the correct equivalent circuit to describe the operating device. In this report, a model p-Si|a-TiO2|Pt photocathode system is used to show that the Maxwell circuit best describes the operating mechanism, as opposed to the more commonly used Voight and nested circuits. This indicates that, under hydrogen evolution conditions, both faradaic and nonfaradaic processes are occurring. Whereas the faradaic process corresponds to the hydrogen evolution reaction itself, the nonfaradaic process is traced to the p-Si|a-TiO2 interface.

Gold-enhanced aptasensors for highly sensitive dengue detection: a cost-effective approach

The reemergence of diseases such as Dengue has spurred the development of efficient biosensing devices. This study aims to establish a rapid, cost-effective, and efficient platform for Dengue detection. The surface of the sensor was constructed by sputtering gold onto fluorine-doped tin oxide thin films, that were previously deposited on glass substrates. Varied sputtering deposition times were used. Results obtained from X-Ray Diffraction analysis showed that the films with 4-minute deposition time had the best gold surface coverage and the best cost-benefit ratio for sensor fabrication. Subsequently, the gold thin films were functionalized with the co-immobilization of a self-organized monolayer of aptamers and 6-mercapto-1-hexanol (MCH). The monolayer was analysed using the electrochemical impedance spectroscopy technique, and the ratio of 1:25 (aptamer: total thiol) was determined for surface optimization. The performance of the aptasensor was tested for the detection of the non-structural protein 1 of Dengue serotype 4 (NS1-S4). A good sensitivity of 40.2 ± 3.7 % per decade and a low detection limit of 1.25 pg/mL were obtained. The development of this platform represents an advance in the fast fabrication of aptasensors for the detection of emerging diseases such as Dengue, contributing also to the miniaturization process of point-of-care devices.

Effects of Incorporating TiO2 Aggregates on the Growth, Anticorrosion, and Antibacterial Properties of Electrodeposited Multifunctional Coatings Based on Sn-Ni Materials

Multifunctional coatings based on Sn-Ni materials with and without titanium oxide nanoparticles (TiO2NPs) incorporation were prepared using the electrochemical deposition technique at 70 °C. TiO2NPs were dispersed in the electrolyte bath, and their influence on the surface texture, crystalline phase, and properties was investigated. Various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray microanalysis (EDX) were used to characterize the prepared coatings. The formation mechanism of the deposited coatings has been demonstrated to be consistent with the electrochemical behavior of instantaneous growth, and the three-dimensional growth is controlled by diffusion phenomena. The anticorrosion effectiveness of the coatings was assessed using potentiodynamic polarization curves and electrochemical impedance spectroscopy in an artificial sweat medium, while the bactericidal activity of the composite coatings (the ability to induce cell death) was evaluated in accordance with the ISO 27447:2019 test. The influence of TiO2NPs at a low concentration of 1 g/L on the composition, structure, and properties of the deposited coatings was demonstrated. Particular attention was paid to the relationship between the anticorrosive and bactericidal properties of the coatings and their structure composition and wetting properties. The synergistic effect of chemical composition and surface-wetting properties has been demonstrated to enhance the anticorrosive and bactericidal properties of the prepared coatings.

Synthesis of tin selenide nanoparticles using Polygonum avicular extract decorated on graphitic carbon nitride for enhancing photodegradation of amoxicillin trihydrate and photoproduction of hydrogen peroxide

In this research, tin selenide nanoparticles (SnSe-NPs) were synthesized using Polygonum avicular extract via the hydrothermal method and decorated on graphitic carbon nitride (g-C3N4) by the simple sonicated method to produce SnSe/g-C3N4 composites. The characterization and properties of the SnSe/g-C3N4 composites, as compared to pristine SnSe and g-C3N4, were determined by Fourier-transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, Mott-Schottky, and electrochemical impedance spectroscopy. As a result, the SnSe-NPs possessed the rod-like shape and after the decoration onto the g-C3N4 sheet surface, it reduced the bandgap energy of the g-C3N4 from 2.58 downward 1.43 eV. Besides, the photoactivities of the 10-SnSe/g-C3N4 catalyst were investigated via both sides of amoxicillin trihydrate (AMXT) photodegradation and hydrogen peroxide (H2O2) photoproduction, in which the results were achieved 87.84 % AMXT and 85.48 μM H2O2, respectively, under visible light. Furthermore, the photodegradation was consistent with the pseudo-first-order kinetics and it performed the highest photodegradation at pH ∼5, while the importance of isopropyl alcohol as a trapping agent and •O2− radicals was affirmed in the H2O2 photoproduction. Moreover, the photoproduction of H2O2 was remained after 4 cycles achieved at 62.70 % in the final cycle, which demonstrated the stability and reusability of the 10-SnSe/g-C3N4. These aforementioned results demonstrate that the SnSe/g-C3N4 material is a promising candidate for addressing environmental pollution and energy scarcity issues.

Structural and electrical characterization of nickel sulfide nanoparticles

Nickel sulfide nanoparticles were successfully synthesized through a meticulous process involving a well-mixed powder of Ni(CH3COO)2∙2H2O and Thiourea. The X-ray diffraction analysis provided insights into the structural nature of NiS, revealing its polycrystalline characteristics with a hexagonal system. This information is fundamental, as it forms the basis for understanding the material’s behavior and functionality in various applications. Determining the average values of mean crystallite size, microstrain, and dislocation Nickel sulfide nanoparticles were successfully synthesized through a careful process involving a well-mixed powder of Ni(II)2∙2H2O and Thiourea. The X-ray diffraction analysis provided insights into the structural nature of NiS, revealing its polycrystalline characteristics with a hexagonal system. This information is crucial as it forms the basis for understanding the material’s behavior and functionality in various applications. Determining the average values of mean crystallite size, microstrain, and dislocation density for the (100) plane (32.62 nm, 0.000296, and 0.000939 nm-2, respectively) contributes to a comprehensive understanding of the material’s structural features. The photoluminescence spectrum of NiS in the visible region revealed split peaks at 405.8 and 428.25 nm, shedding light on the radiative recombination process between electrons and holes. The confirmation of thermal stability through a thermogravimetry diagram is essential for applications in elevated temperature environments, ensuring the material’s reliability under varying conditions. Analyzing the stoichiometry of NiS using energy dispersive spectroscopy attached to transmission electron microscopy provides insights into the material’s composition. Cyclic voltammetry results indicating a diffusion coefficient greater than that of NiS added to carbon hold significance for electrochemical applications. The unique characteristic peaks observed in cyclic voltammetry for fuel cell applications suggest the potential use of NiS in energy conversion technologies, broadening its scope of application. The confirmation of NiS’s ability to elucidate the physical and electronic properties of electrochemical systems through electrochemical impedance spectroscopy underlines its importance as a versatile material in various research and practical domains.

Nano Material Innovation in Enhancing Corrosion Resistance of Offshore Structures

Offshore structures are constantly exposed to the corrosive marine environment, causing significant material degradation and potentially jeopardizing structural integrity. This research explores recent innovations in nanomaterial technology to improve the corrosion resistance of offshore structures. The main focus is given to the development of nano-composite coatings incorporating metal oxide nanoparticles and carbon nanotubes. An electrophoretic deposition method was used to apply the coatings on steel substrates, followed by characterization using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Results showed a significant improvement in corrosion resistance, with the nano-composite coatings exhibiting a reduction in corrosion rate of up to 85% compared to conventional coatings. In addition, these coatings exhibited superior adhesion and abrasion resistance in simulated extreme marine conditions. These findings highlight the great potential of nanomaterials in extending the service life and improving the reliability of offshore structures, with important implications for the oil and gas and offshore renewable energy industries.

Electrochemical performance of cobalt-doped NiO thin films synthesized by spray pyrolysis

ABSTRACT In this work, various cobalt-doped NiO thin films have been synthesized via the spray pyrolysis. The cobalt-doped NiO thin films show a cubic phase with preferred orientation along the (111) plane. The scanning electron microscopy images of the cobalt-doped NiO thin films show interconnected flakes with small agglomerated particles. The optical bandgap decreases from 3.30 eV for the undoped NiO thin film to 2.90 eV for 20 mol% cobalt doping, with an increase in cobalt doping concentration in NiO. The electrochemical activities have been tested in 2M KOH electrolyte with cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The highest specific capacitance observed for the 10 mol% cobalt-doped NiO thin film electrode is 760 Fg−1 at a scan rate of 5 mVs−1. The 10 mol% cobalt-doped NiO thin film electrode shows 92% retention in capacitance after 1000 cycles and a low charge transfer resistance of 10 Ωcm2.

Synthesis, Structural, Morphology and Magnetic Properties: Effect of La on Multiferroic Nature of BiFeO3 Nanoparticles

Objectives: The present study focuses on developing La-doped BiFeO3 multiferroic materials for dielectric absorber applications. Methods: The samples are characterized by X-ray Diffractometer (XRD). Further, the morphology is examined using field emission electron microscopy (FESEM) and Transmission Electron Microscopy (TEM). The dielectric parameters and ac-electrical parameters are carried out by impedance spectroscopy. The magnetic properties are studied using a vibrating sample magnetometer VSM, P-E loop. Findings: XRD confirms the rhombohedral (trigonal) structure of BLFO nanoparticles. The grain and particle size values are determined by SEM and TEM, respectively. The dielectric and ac-electrical parameters for all the samples are thoroughly discussed at room temperature. The Maxwell-Wagner or interfacial polarization is noticed at low input field frequencies for x=0.2-0.8. The impedance analysis shows the contribution of grain and its boundary in the electrical conduction mechanism. The multiferroic behavior is examined using M-H loops, P-E loops, and μi-f plots. Novelty: The samples are synthesized by the hydrothermal process to prepare La-doped BiFeO3 nanomaterials. Keywords: Nanoparticles, Electron Microscopy, Multiferroic, Magnetization, Polarization, Permeability

Synergistic insights to ion-doped hydroxyapatite: bridging XRD, electrical impedance, dielectric characteristics, and antibacterial properties

ABSTRACT In this work, ion-doped hydroxyapatite materials were synthesized using the sol-gel technique. XRD analysis confirmed the purity of the products, with no secondary peaks observed. Doping with manganese, lithium, potassium, and zinc ions resulted in a crystalline size of 47–48 nm. Fourier transform infrared spectroscopy validated the structural bands, while scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed nano-rod-like particles with sizes ranging from 30 to 80 nm in length and 13 to 40 nm in width. Impedance spectroscopy and dielectric relaxation studies showed electrical behaviour following the Maxwell-Wagner mechanism and non-Debye type relaxation. The materials exhibited strong antibacterial properties, making them promising for medical implant applications.