High-entropy alloys (HEAs) offer a distinctive framework for tailoring surface affinities to reaction intermediates, enabling the design of efficient electrocatalysts. Notably, the heterogeneous interfaces within HEAs play a pivotal role in enhancing both intrinsic catalytic activity and durability, driven by the synergistic interactions among multiple metal atoms. Herein, a heterostructured bifunctional electrocatalyst, CrFeCoNiRu-RuNi (HEA-RuNi), is demonstrated to exhibit exceptional hydrogen and oxygen evolution reaction (HER and OER) activities, delivering overpotentials of 48 and 249 mV for HER and OER, respectively, at a current density of 10 mA cm-2 in alkaline media, and robust stability in an anion exchange membrane water electrolysis device for 200 h. In situ Raman spectroscopy and electrochemical impedance spectroscopy revealed that the unique heterostructure of HEA-RuNi effectively modulates the local Ru microenvironment, redistributing the interfacial water hydrogen bond network within the electrochemical double layer, which facilitates water adsorption and dissociation. Theoretical calculations further unravel that the heterointerface of HEA-RuNi enables to tailoring of the electronic structure of the Ru active site, thus facilitating water dissociation in HER and moderating the adsorption ability of reaction intermediates in OER. The present work provides an insightful understanding of interficial engineering for electrocatalyst design in the field of energy storage and conversion.

Graphical abstract Diagram illustrating film formation processes and interfacial compatibility, concluding with graphs depicting corrosion behavior across various frequencies and time points. The image presents a multi-part diagram showcasing processes related to film formation and interfacial compatibility on a substrate. On the left, two sections depict film formation mechanisms (a and b), illustrating resin and curing agent clusters, along with water evaporation leading to film creation. The centre section outlines interfacial compatibility with covalent bonds illustrated by labeled diagrams (with reference numbers 718 and 719) showing coatings like carboxylate salts. On the right, there are graphs labeled (a), (b), and (c) demonstrating corrosion behavior over different frequencies measured in Hertz, plotting logarithmic impedance against frequency with various data points representing time intervals. Each graph includes a fitting line, capturing the data flow left to right and bottom to top. Purpose This paper aims to investigate the comprehensive corrosion resistance of various film-forming and curing types of resins on the surfaces of typical aluminum alloys. Design/methodology/approach The chemical composition and surface morphology of coatings, including 718, 719 and epoxy resins, were analyzed using infrared spectroscopy and laser confocal microscopy. Contact angle measurements were performed to evaluate the wettability of different coatings. Furthermore, the interfacial bonding performance between waterborne resin coatings and aluminum alloy substrates, as well as the spatio-temporal evolution of coating corrosion resistance under NaCl solution immersion, was assessed through electrochemical impedance spectroscopy (EIS) and adhesion testing. Findings Both thermoplastic and thermosetting resins were found to form continuous and complete film layers on the surfaces of aluminum alloys. Under conditions of comparable surface integrity and contact angles, distinct differences in interfacial stability were observed among the various resin systems. These variations in interfacial compatibility between coatings and substrates were characterized using EIS and adhesion tests. Originality/value This study establishes a theoretical foundation for the development of high-performance and durable waterborne anticorrosion coatings.

Purpose The purpose of this study is to prepare CS-TiO2/salicylaldehyde Schiff bases using two different molecular weights of chitosan (CS): low molecular weight and medium molecular weight were used to prepare CS-TiO2/salicylaldehyde Schiff bases and investigate these two compounds, as corrosion inhibitors for copper in 1 M HCl solution using electrochemical impedance spectroscopy and cyclic potentiodynamic polarization measurements. Design/methodology/approach CS-TiO2/salicylaldehyde Schiff bases using two different molecular weight of CS were prepared first by mixing CS in 10% acetic acid (10 mL) with TiO2, second adding salicylaldehyde to the solution with modifying pH of the medium to 6 by using (2 M) of NaOH, product was obtained by filtration and washed several times to get rid of any unreacted salicylaldehyde. Four different concentrations were prepared: 50, 100, 200 and 500 ppm to study the corrosion inhibitor properties of CS-TiO2/salicylaldehyde Schiff bases. Findings Fourier transform infrared spectroscopy analysis indicates that the characteristic peak of the -NH2 group in CS disappeared, confirming the reaction between amine groups in CS and the aldehyde group in salicylaldehyde, which indicates the formation of Schiff base. X-ray diffraction analysis confirms the formation of CS-TiO2/salicylaldehyde Schiff bases; the TiO2 crystallinity did not affect during Schiff base formation. Thermogravimetric analysis shows an improvement in thermal behavior in CS-TiO2/salicylaldehyde Schiff bases than in CS itself, with a maximum degradation rate found to be at 355.2°C by using the derivative thermogravimetric (DTG) curve. The polarization tests show that the effect of inhibiting the copper corrosion was highly increased in the presence of 100 ppm of low molecular weight CS in CS-TiO2/salicylaldehyde Schiff base than in the presence of 100 ppm of medium molecular weight CS in CS-TiO2/salicylaldehyde Schiff base. The electrochemical corrosion experiments proved that both molecular weights of CS Schiff base exhibited a good inhibiting property for copper in 0.1 M HCl. Low molecular weight CS Schiff base shows better performance as a corrosion inhibitor than the medium molecular weight CS. At 100 ppm concentration, the corrosion current density (jCorr) was lower for the low molecular weight inhibitor (0.69 mAcm−2) compared to (0.90 mAcm−2) for the medium molecular weight. This funding refers to a low molecular weight CS Schiff base that was more effective at slowing down the corrosion process, likely due to its smaller size allows it to better cover and stick to the copper surface, forming a stronger protective barrier against corrosive agents. This result was further confirmed by the analysis of the surface using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS). The influence of corrosive attack on copper surfaces was examined using an SEM and EDS. Originality/value This study aims to determine which molecular weight of CS Schiff base is the most effective as a corrosion inhibitor. This study will serve as a foundation for future work involving low molecular weight CS Schiff bases and testing their potential as corrosion inhibitor agents on various metals, such as aluminum and steel.

Purpose This study aims to propose a new type of double-layer coating system composed of an electroplating nickel layer and a hydrothermally grown bayerite [ß-Al(OH)3] coating on a 1060 aluminum alloy substrate, aiming to enhance the corrosion resistance of aluminum alloys in the application environments of aerospace, automotive and marine industries. Design/methodology/approach The nickel layer was obtained via constant current electrodeposition, and then the bayerite layer was grown in situ through hydrothermal treatment at 125 °C with different durations (3, 6, and 12 h). The microstructure and chemical composition of the Ni layer and bayerite layer were investigated by scanning electron microscope, energy dispersive spectroscopy, X-ray diffractometer and X-ray photoelectron spectroscopy. Their corrosion resistance was verified using electrochemical impedance spectroscopy and immersion tests. Findings Electrochemical tests in 3.5 Wt.% NaCl solution revealed that the Ni/Bayerite-6h coating exhibited the highest corrosion resistance, with a corrosion current density of 4.42 × 10−7A·cm−2 (three orders of magnitude lower than the Ni layer) and a polarization resistance of 513951 Ω·cm2. Long-term immersion tests showed that the Ni/Bayerite-6h coating delayed corrosive medium penetration for up to five days and can still prevent galvanic corrosion between the nickel layer and the aluminum substrate after seven days, significantly suppressing galvanic corrosion at the nickel–aluminum interface. The bayerite coating effectively isolates the pinholes and grain boundary gaps in the Ni layer and forms a dual-layer structure with it, providing a strong barrier against the intrusion of chloride ions. Originality/value This work demonstrates a viable strategy to enhance the durability of aluminum alloys through engineered multilayer coatings.

In this experimental work, silver tungstate nanostructures were fabricated by a simple combustion synthesis method utilizing sucrose molecules as a new environmentally friendly fuel and structure-controlling agent. Subsequently, a carbon paste electrode (CPE) was modified with the Ag2WO₄ nanocomposite and an ionic liquid (IL) to exploit the synergistic effects of both materials, yielding a cost-effective and highly efficient platform for the electrochemical detection of Vortioxetine (VRT). The Ag2WO₄/IL-modified CPE exhibited markedly enhanced electrochemical activity compared to the bare electrode, as evidenced by the increased oxidation currents and reduced charge-transfer resistance observed in cyclic voltammetry and electrochemical impedance spectroscopy analyses. The sensor demonstrated excellent linearity across a wide concentration range (0.03-60µM) under optimized conditions, with a detection limit of 0.01µM, indicating high sensitivity in adsorptive differential pulse voltammetry (AdsDPV) measurements. Additionally, the platform displayed excellent selectivity, stability, and reproducibility, with recovery values between 97.0 and 103.3% and relative standard deviation (RSD) values from 2.1 to 3.6%. The findings affirm the potential of the Ag2WO₄/IL/CPE sensor for precise quantification of VRT in biological fluids and pharmaceutical formulations. This work presents a promising electrochemical sensing strategy with potential extensions to other neuroactive drugs in clinical diagnostics.

Abstract Electrochemical impedance spectroscopy (EIS) represents a promising and rapidly growing biosensing technique, enabling researchers and clinicians to perform label-free analyte detection; however, the scarcity of small, low-cost, and energy-efficient mobile devices for impedance measurement presents a major obstacle to further utilization of this method. Many EIS analog frontend (AFE) integrated circuits meeting these criteria are not commercially available; equivalent discrete circuits are frequently too expensive, large, or energy-inefficient for broad deployment. We present a discrete EIS-AFE which encodes impedance magnitude and phase as DC potentials; our AFE is optimized to minimize energy expenditure (< 21 µJ per point at 10 kHz), size (< 91 mm2 for the detector circuits), computational overhead (requiring only three ADC samples), and design complexity to target edge sensing applications (such as single-frequency EIS). We characterize the performance of the custom AFE, perform a comparative power analysis, and demonstrate successful EIS sensing using a series of dummy cells and a synthetic tissue analog saturated with artificial sweat. Our AFE enables accurate acquisition of impedance data with considerable power and cost savings relative to similar devices, while enabling modular expansion of the system to facilitate EIS sensing in a variety of mobile sensing applications.

For sustainable corrosion protection, this study introduces newly synthesized pyrazolyl-N-acetylthiocarbohydrazone (PTH) as a highly efficient and environmentally friendly inhibitor for carbon steel (CS) in an aggressive 1.0 M HCl solution. A comprehensive evaluation of PTH inhibition performance was conducted through chemical weight loss and electrochemical techniques, involving potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), which demonstrated a significant reduction in CS corrosion. PDP and EIS reinforced these findings, confirming the robust protective nature of PTH with an inhibition potency of 96%. The mitigation power of the PTH can be explained by its adsorption onto the CS surface, which followed the Langmuir adsorption model. The inhibitor exhibited exceptional stability and efficiency across varying temperature conditions and various immersion times using EIS, reinforcing its reliability in harsh acidic media, with a mitigation capacity of 97.16% at 50 °C and 97.3% after 24 h. The morphology of the CS surface was examined using SEM /EDX (Scanning Electron Microscopy), AFM (Atomic Force Microscopy), and XPS (X-ray Photoelectron Spectroscopy), exhibiting the PTH adsorption over CS, which was also proved and elucidated employing theoretical quantum investigations as density functional theory and Monte Carlo simulations.

Electrochemical impedance spectroscopy (EIS) is one of the essential tools for probing interfacial charge transfer in electrochemical systems. Transforming impedance data into alternative domains can reveal hidden processes that are masked in the frequency domain. In the present study, we investigate glucose oxidation on NiO by combining electrochemical capacitance spectroscopy (ECS) and the distribution of relaxation times (DRT). NiO was prepared via thermal decomposition and characterized structurally. Then, we show how capacitance analysis separates double layer and pseudocapacitive contributions, while DRT provides time-resolved insights into the individual electrochemical steps. Using ECS, we observe that increasing glucose concentration (0 to 5 mM) enhances pseudocapacitance and reduces charge transfer resistance. ECS also reveals that the low frequency capacitance increases linearly with glucose concentration, whereas the double layer capacitance remains constant. On the other hand, DRT spectra exhibit two peaks, which we attribute to two processes: a fast process associated with OH- adsorption and a slower process attributed to direct glucose oxidation. The dominant peak shifts to shorter relaxation times and decreases in amplitude with increasing glucose, consistent with accelerated kinetics and lower resistance. DRT signatures of ascorbic acid, dopamine and uric acid differ from that of glucose, demonstrating selectivity. These findings establish, for the first time, the DRT as a powerful time scale domain transduction method that critically complements ECS, and offers mechanistic insights for the advanced design of non-enzymatic glucose sensors for diabetes monitoring.

Sulfated nanocellulose (SCNF) and reduced graphene oxide (rGO) films were fabricated through environmentally friendly methods to develop an effective platform for electrochemical applications. The hybrid materials were extensively characterized by FTIR, XRD, Raman spectroscopy, TGA, SEM, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Results showed that incorporating rGO into the SCNF matrix significantly improved the electrical conductivity and structural robustness of the films. FTIR confirmed interactions between sulfate groups on cellulose and residual oxygen-containing groups on rGO, while XRD and Raman analyses indicated reduced crystallinity and increased structural disorder, supporting the successful integration of both phases. XPS further demonstrated that SCNF and rGO form chemical bonds rather than simply mixing, with both components remaining active at the surface—evidence of strong interfacial interactions that contribute to enhanced stability and efficient charge transfer. The 1:5 (rGO:SCNF) composition showed the best electrochemical performance, exhibiting minimal charge-transfer resistance and improved hydrazine oxidation, as reflected by a shift of the anodic peak potential toward lower values. Additionally, functionalization with cobalt porphyrin significantly boosted catalytic activity. Overall, the SCNF:rGO films offer a sustainable and scalable platform for electrochemical sensing and energy-conversion applications, demonstrating excellent adaptability and functional performance.

ABSTRACT Electrochemical CO₂ reduction using solid oxide electrolysis cells (SOECs) directly converts CO 2 into value‑added chemicals, mitigating greenhouse‑gas emissions. Nickel (Ni) is the conventionally used fuel‑electrode electrocatalyst, yet its intrinsic catalytic behavior is underexplored. This study systematically evaluates Ni alloyed with 5 at% Fe, Co, or Cu for changes in microstructure, electrochemical activity, and carbon coking resistance. Model electrodes fabricated by pulsed laser deposition are analyzed by scanning and transmission electron microscopy, X‑ray diffraction, and X‑ray absorption spectroscopy, which confirm homogeneous alloy formation and show that additive metals modulate active site density by modulating sintering behavior, thereby tuning the triple‐phase‐boundary density in the order Ni > Ni–Cu > Ni–Co > Ni–Fe. Electrochemical impedance spectroscopy reveals that the apparent activation energy ( E a ) related to surface reaction decreases for all samples, accelerating CO 2 electrolysis, while sensitivity to the CO/CO 2 ratio rises when the alloying element is less prone to CO 2 dissociation. Diffuse reflectance Fourier‑transform infrared spectroscopy and density functional theory calculations indicate that Co and Fe facilitate CO 2 dissociation, whereas Cu facilitates fast desorption of product species and enhances turnover activity. Cu alloying markedly suppresses carbon coking, whereas Co exacerbates it. Enhanced performance and durability are validated by impedance and Galvano‐static measurements. These findings demonstrate that Ni–Cu alloy electrodes offer a practical route to boost SOEC efficiency and mitigate coking with minimal structural change.

Anion exchange membrane water electrolysis (AEMWE) has become a promising technology for generating hydrogen in a carbon-neutral economy. However, its competitiveness is currently limited by the low durability of AEMWE systems. To increase its durability and to advance its industrial application, this study examines the degradation behavior of a 25 cm2 AEMWE cell utilizing non-precious metal catalysts and pure water feed in a short-term durability test. Polarization curves and electrochemical impedance spectroscopy, along with scanning electron microscopy and energy-dispersive X-ray spectroscopy, are employed to identify factors affecting cell efficiency and stability. The pure-water-fed AEMWE cell exhibits high performance losses and low stability that is mainly related to degradation in the anode and at the interface of anode and membrane. Ionomer degradation, reducing hydroxide ion conductivity, and mechanical stability of the catalyst layer, is identified as the key factor decreasing cell efficiency and stability during pure water operation. The findings aim to guide the development of strategies to enhance cell performance and durability of pure-water-fedAEMWE.

In this work, a sensitive and efficient light enhanced electrochemical dopamine sensor based on tungsten oxide nanoparticles electrodeposited on MXene nanosheets modified pencil graphite electrode (MXene-WOx/PGE) was reported. The prepared substrate was carefully characterized with field emission scanning electron microscopy, energy dispersive X-ray analysis, Raman spectroscopy, electrochemical impedance spectroscopy and voltammetry techniques in details. The surface area of MXene-WOx/PGE was increased 3.75 times in compare with WOxNPs/PGE proving the role of MXene as a suitable 2D nanomaterials on the electrode surface. The synergistic effect of 2D MXene and tungsten oxide nanoparticles resulted an improved light current response and admirable photocatalytic properties. Linear range, sensitivity and detection limit of the prepared photoelectrochemical sensor for dopamine were reported to be 10-400 nM, 0.028mA nM- 1 and 1 nM respectively. The proposed sensor was utilized for photoelectrochemical detection of dopamine in serum samples with suitable reproducibility, stability and selectivity.

In the oil and gas industry, carbon steel is widely used but suffers from severe corrosion in acidic environments, particularly in the presence of CO₂ and H₂S. This study presents the synthesis and evaluation of a novel eco-friendly compound, 2,2'-(4,6-dihydroxyisophthaloyl) bis(N-phenylhydrazine-1-carbothioamide) (DICA), as an effective corrosion inhibitor for low-carbon steel in 0.5M HCl solution. Structural characterization was confirmed through NMR, elemental analysis, and mass spectrometry. The corrosion inhibition performance was investigated using weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). DICA demonstrated outstanding inhibition efficiency, reaching 91.41% at 300 ppm concentration and 298K, indicating a strong concentration-dependent protective effect. Surface morphology analysis by SEM and AFM revealed a significant reduction in steel surface roughness and corrosion damage due to DICA adsorption. Complementary density functional theory (DFT) calculations and Monte Carlo simulations corroborated the mixed-mode adsorption mechanism involving both chemisorption and physisorption. These findings confirm the potential of DICA as a high-performance, environmentally benign inhibitor for protecting carbon steel in aggressive acidic media.

Ions play a fundamental role in solid-liquid interface processes, whether as essential or undesirable components, highlighting the need for precise and quantitative real-time monitoring. Electrochemical sensors are identified as promising tools, particularly for field-deployable applications. However, conventional electrochemical sensing is inherently restricted to redox-active species and is often single use, constraining its scope. This study presents electrochemical impedance spectroscopy as an alternative for ion detection, utilizing physico-chemical interactions at the electrode-electrolyte interface. We introduce a first-principles model that describes the interfacial impedance behavior and shows how ion specific processes shape the impedance response. Based on this framework, an extensive dataset is compiled, and a machine learning model is trained to predict electrolyte composition with consistent accuracy, demonstrating detection limits at the parts-per-billion level. The findings indicate that this method has considerable potential as a real-time method for ion sensing, providing a perspective on selectivity and sensitivity beyond traditional electrochemical approaches. This work could serve as a foundation for advanced models of impedance behavior, and development of impedance-based sensors with applicability in complex environments, including biological fluids and industrial liquids.

Abstract Silicon-tin (Si-Sn) nanocomposites are viable anode substitutes for lithium-ion batteries (LIBs) as they have the high theoretical storage capacities of lithium (4200 mAh g -1 (Si) and 994 mAh g -1 (Sn)), which are significantly more than those of graphite (372 mAh g -1 ). The Si and Sn cannot be used widely due to their extreme volume expansion during cycling, which results in limited structural stability and quick capacity deterioration. Herein, a nanocomposite based on reduced Graphene Oxide and nanoparticles containing silicon and tin species (SnSi9@rGO) is presented as a potential solution to mitigate these challenges by incorporating rGO to enhance the electrochemical performance. This nanocomposite demonstrates a high discharge capacity of 1506.91 mAh g -1 at a current density of 0.55 A g -1 after 205 cycles. In contrast, the SnSi9 nanoparticles only kept 125.85 mAh g -1 after the same number of cycles. SnSi9@rGO nanocomposite improved electrochemical performance due to the conductive network provided by rGO, which adapts to volume variations during cycling and facilitates charge transfer. Results from galvanostatic testing, cyclic voltammetry, and electrochemical impedance spectroscopy support the idea that SnSi9@rGO nanocomposites could be a high-performance anode material for next-generation LIBs.

Protocol for monitoring the growth of Solanum betaceum non-embryogenic callus using electrochemical impedance spectroscopy.

The removal capacity, iron and phosphorus forms, and microbial distribution of low concentration phosphorus by electrolytic biochar biofilter.

Corrosion of steel has several catastrophic consequences in various sectors. The inorganic nanoparticle-based anticorrosive coating on steel drew important attention to its large surface-to-volume ratio. The primary aim of this study is to synthesize and characterize t-ZrO2 nanoparticles at an optimized annealing temperature and evaluate their structural, morphological, and optical properties. Additionally, the study investigates their effectiveness as a corrosion inhibitor for carbon steel in 1M H2SO4. The study explores the cheap, facile, green synthesis of t-ZrO2 nanoparticles (NPs) through bark extract from the gum arabic plant (Acacia nilotica) for anticorrosive coatings on carbon steel. X-ray diffraction (XRD) analysis confirms the tetragonal phase structure and the crystallite size, calculated using Scherrer's formula, is found to be 8.1nm. Fourier-transform infrared (FT-IR) spectroscopy reveals the presence of Zr-O bonding along with organic residues from plant extracts, confirming the formation of t-ZrO2 NPs. Field emission scanning electron microscopy (FESEM) images confirm a rock stone-like structure, while energy dispersive X-ray (EDX) spectroscopy verifies the presence of Zr and O elements. The study further investigates the corrosion inhibition efficiency of t-ZrO2 NPs on carbon steel in 1M H2SO4. The atomic force microscopy (AFM) analyses reveal a smoother surface with reduced roughness in the presence of the inhibitor. Electrochemical measurements, including weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), confirm a significant reduction in corrosion rate. The inhibition efficiency reaches 95.2% at 200ppm of 0.2M t-ZrO2 NPs, with an increased charge transfer resistance (Rct) of 14,715Ωcm2 and a reduced double-layer capacitance (Cdl) of 0.631 × 10⁸F/cm2. These findings demonstrate that t-ZrO2 NPs act as an effective corrosion inhibitor for carbon steel in acidic environments.

Scalable flexographic printing of graphite/carbon dot nanobiosensors for non-faradaic electrochemical quantification of IL-8.

State of charge estimation in zinc‑iron flow battery based on electrochemical impedance spectroscopy with flow/temperature compensation