This work investigates the reaction kinetics in a highly concentrated (×50) mixture of calcium sulfate (CaSO₄) and sodium fluoride (NaF) using real-time, in-situ Electrochemical Impedance Spectroscopy (EIS) over 48 h. The primary objective was to establish the electrochemical profile and monitor ion transport dynamics under aggressive, non-equilibrium conditions designed to accelerate precipitation kinetics. Analysis of the complex conductivity spectra (σ′ and σ′′) and Nyquist plots, modeled with an equivalent electrical circuit R₁(R₂//CPE), revealed two distinct kinetic regimes. The temporal evolution of the dc conductivity (σ₀) showed an initial decrease, followed by a rise, culminating in stabilization after approximately 19 h. This stabilization is interpreted as the establishment of a dynamic equilibrium state. Concurrent trends in the high-frequency conductivity (σ∞), CPE exponent (p), and relaxation time (τ) suggest significant microstructural evolution within the system. While the electrochemical data are consistent with the expected precipitation of CaF₂ and provide a kinetic profile suggesting a potentially faster route to equilibrium than traditional methods, this study focuses on establishing EIS as a monitoring tool. Direct analytical confirmation of the solid phase and quantitative yield analysis are recognized as essential next steps and are the focus of immediate future work.
{"title":"Time-resolved electrochemical impedance spectroscopy study of calcium fluoride formation and ion transport dynamics in highly concentrated CaSO₄–NaF systems","authors":"Meryem Bensemlali , Halima Mortadi , Abdellatif Aarfane , Abdoullatif Baraket , Abdelowahed Hajjaji , Fouad Belhora , Mina Bakasse , Najoua Labjar , Said Laasri , Hamid Nasrellah","doi":"10.1016/j.ijoes.2025.101249","DOIUrl":"10.1016/j.ijoes.2025.101249","url":null,"abstract":"<div><div>This work investigates the reaction kinetics in a highly concentrated (×50) mixture of calcium sulfate (CaSO₄) and sodium fluoride (NaF) using real-time, in-situ Electrochemical Impedance Spectroscopy (EIS) over 48 h. The primary objective was to establish the electrochemical profile and monitor ion transport dynamics under aggressive, non-equilibrium conditions designed to accelerate precipitation kinetics. Analysis of the complex conductivity spectra (σ′ and σ′′) and Nyquist plots, modeled with an equivalent electrical circuit R₁(R₂//CPE), revealed two distinct kinetic regimes. The temporal evolution of the dc conductivity (σ₀) showed an initial decrease, followed by a rise, culminating in stabilization after approximately 19 h. This stabilization is interpreted as the establishment of a dynamic equilibrium state. Concurrent trends in the high-frequency conductivity (σ∞), CPE exponent (p), and relaxation time (τ) suggest significant microstructural evolution within the system. While the electrochemical data are consistent with the expected precipitation of CaF₂ and provide a kinetic profile suggesting a potentially faster route to equilibrium than traditional methods, this study focuses on establishing EIS as a monitoring tool. Direct analytical confirmation of the solid phase and quantitative yield analysis are recognized as essential next steps and are the focus of immediate future work.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"21 1","pages":"Article 101249"},"PeriodicalIF":2.4,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.ijoes.2025.101242
Ananya S. Agnihotri, M. Nidhin
In this study, we present a highly selective and sensitive electrochemical sensor for the detection of Amlodipine besylate (AMP) using α-Fe2O3 nanoparticles (IO) functionalized with alanine (IOALA) to enhance electrochemical activity. The IO nanoparticles were synthesized through a starch-assisted template method and then modified with alanine, improving their stability and reducing agglomerate size. Comprehensive characterization of IOALA was conducted using XRD, FTIR, DLS, VSM, FESEM-EDX, HRTEM, and SAED, confirming the structural integrity and functionalization of the nanomaterial. The IOALA was subsequently immobilized on a glassy carbon electrode (GCE) to fabricate the IOALA/GCE sensor, where electrochemical parameters, including scan rate, electrolyte pH, and AMP concentration, were meticulously optimized. Differential pulse voltammetry (DPV) was employed to achieve precise quantification of AMP, revealing a remarkable detection limit of 1.29 nM and a broad linear dynamic range of 3.89 nM to 500.03 nM. The sensor demonstrated excellent reproducibility and selectivity, exhibiting high resistance to interference, making it reliable for real-sample analysis. Practical application was validated by detecting AMP in generic drug formulations, highlighting the sensor's potential for real-world pharmaceutical monitoring. This novel IOALA/GCE platform offers an efficient, cost-effective, and robust approach for AMP detection, contributing to the advancement of electrochemical sensors in pharmaceutical analysis.
{"title":"Highly sensitive and selective electrochemical detection of amlodipine besylate using β-alanine-modified α-Fe₂O₃ nanoparticles","authors":"Ananya S. Agnihotri, M. Nidhin","doi":"10.1016/j.ijoes.2025.101242","DOIUrl":"10.1016/j.ijoes.2025.101242","url":null,"abstract":"<div><div>In this study, we present a highly selective and sensitive electrochemical sensor for the detection of Amlodipine besylate (AMP) using α-Fe<sub>2</sub>O<sub>3</sub> nanoparticles (IO) functionalized with alanine (IOALA) to enhance electrochemical activity. The IO nanoparticles were synthesized through a starch-assisted template method and then modified with alanine, improving their stability and reducing agglomerate size. Comprehensive characterization of IOALA was conducted using XRD, FTIR, DLS, VSM, FESEM-EDX, HRTEM, and SAED, confirming the structural integrity and functionalization of the nanomaterial. The IOALA was subsequently immobilized on a glassy carbon electrode (GCE) to fabricate the IOALA/GCE sensor, where electrochemical parameters, including scan rate, electrolyte pH, and AMP concentration, were meticulously optimized. Differential pulse voltammetry (DPV) was employed to achieve precise quantification of AMP, revealing a remarkable detection limit of 1.29 nM and a broad linear dynamic range of 3.89 nM to 500.03 nM. The sensor demonstrated excellent reproducibility and selectivity, exhibiting high resistance to interference, making it reliable for real-sample analysis. Practical application was validated by detecting AMP in generic drug formulations, highlighting the sensor's potential for real-world pharmaceutical monitoring. This novel IOALA/GCE platform offers an efficient, cost-effective, and robust approach for AMP detection, contributing to the advancement of electrochemical sensors in pharmaceutical analysis.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"21 1","pages":"Article 101242"},"PeriodicalIF":2.4,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.ijoes.2025.101241
Yikun Wang, Wei Zhao, Yang Chen
The accurate monitoring of sulfur dioxide (SO2) at parts-per-billion (ppb) concentrations is critical for safeguarding public health and managing environmental quality. This review provides a critical comparative analysis of two prominent technologies for ppb-level detection: electrochemical (EC) sensors and Quantum Cascade Laser Photoacoustic Spectroscopy (QCL-PAS). These technologies represent a fundamental trade-off in modern gas sensing, pitting the low cost, scalability, and low power consumption of EC sensors against the superior sensitivity, selectivity, and stability of QCL-PAS. This paper delves into the materials science innovations driving the performance of EC sensors, including metal-oxide semiconductors, 2D materials, and metal-organic frameworks, while critically examining the persistent challenges of environmental susceptibility, cross-sensitivity to interfering gases, and long-term drift that complicate their field deployment. In parallel, the principles of QCL-PAS are detailed, highlighting system design advancements such as differential photoacoustic cells and quartz-enhanced photoacoustic spectroscopy that enable sub-ppb detection limits. The inherent limitations of this optical method, particularly the adsorption-desorption "memory effect" with polar molecules like SO2 and the influence of background gas composition on signal intensity, are thoroughly discussed. The analysis concludes that these technologies are not merely competitors but occupy distinct and complementary niches. Electrochemical sensors are ideally suited for high-density, spatially resolved monitoring networks where identifying trends and hotspots is prioritized, whereas QCL-PAS excels in applications demanding high-fidelity, legally defensible data, such as regulatory compliance, industrial process control, and reference-grade monitoring. The future of comprehensive SO2 monitoring likely lies in hybrid systems that leverage the strengths of both technologies, using high-accuracy QCL-PAS instruments to validate and calibrate vast networks of low-cost electrochemical sensors.
{"title":"A comparative review of electrochemical sensing and QCL-based photoacoustic spectroscopy for ppb-Level SO₂ detection","authors":"Yikun Wang, Wei Zhao, Yang Chen","doi":"10.1016/j.ijoes.2025.101241","DOIUrl":"10.1016/j.ijoes.2025.101241","url":null,"abstract":"<div><div>The accurate monitoring of sulfur dioxide (SO<sub>2</sub>) at parts-per-billion (ppb) concentrations is critical for safeguarding public health and managing environmental quality. This review provides a critical comparative analysis of two prominent technologies for ppb-level detection: electrochemical (EC) sensors and Quantum Cascade Laser Photoacoustic Spectroscopy (QCL-PAS). These technologies represent a fundamental trade-off in modern gas sensing, pitting the low cost, scalability, and low power consumption of EC sensors against the superior sensitivity, selectivity, and stability of QCL-PAS. This paper delves into the materials science innovations driving the performance of EC sensors, including metal-oxide semiconductors, 2D materials, and metal-organic frameworks, while critically examining the persistent challenges of environmental susceptibility, cross-sensitivity to interfering gases, and long-term drift that complicate their field deployment. In parallel, the principles of QCL-PAS are detailed, highlighting system design advancements such as differential photoacoustic cells and quartz-enhanced photoacoustic spectroscopy that enable sub-ppb detection limits. The inherent limitations of this optical method, particularly the adsorption-desorption \"memory effect\" with polar molecules like SO<sub>2</sub> and the influence of background gas composition on signal intensity, are thoroughly discussed. The analysis concludes that these technologies are not merely competitors but occupy distinct and complementary niches. Electrochemical sensors are ideally suited for high-density, spatially resolved monitoring networks where identifying trends and hotspots is prioritized, whereas QCL-PAS excels in applications demanding high-fidelity, legally defensible data, such as regulatory compliance, industrial process control, and reference-grade monitoring. The future of comprehensive SO<sub>2</sub> monitoring likely lies in hybrid systems that leverage the strengths of both technologies, using high-accuracy QCL-PAS instruments to validate and calibrate vast networks of low-cost electrochemical sensors.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"21 1","pages":"Article 101241"},"PeriodicalIF":2.4,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-16DOI: 10.1016/j.ijoes.2025.101240
Seyed Mohammad Razavi , Toktam Aghaee
In this paper, a proposed structure of SOI-MESFET with two intrinsic semiconductor layers at the top of the channel and an area with additional impurities in the channel bottom (IA-SOI) is presented. In addition to this structure, the transistor, which has only two intrinsic semiconductor layers at the top of the channel (I-SOI), is tested to determine the importance of the layer with more impurities in the channel bottom of IA-SOI. Some of the most important electrical parameters of the proposed transistors are studied and compared with those of the conventional structure (C-SOI). These parameters include drain current, electric field, breakdown voltage, gate-source capacitor, output resistance, maximum output power density and threshold voltage. The two intrinsic semiconductor layers of IA-SOI improve the breakdown voltage of this transistor by 45 % and reduce the gate-source capacitor by 18 % compared to those of the C-SOI. Also, the layer with additional impurities in the channel bottom of the proposed structure increases the drain current by 100 %. Simultaneous increase of drain current and breakdown voltage in IA-SOI significantly increases the maximum power density of this transistor compared to the conventional one. Comparing I-SOI with the conventional structure, it can be concluded that I-SOI increases the output resistance by 100 % compared to that in the C-SOI structure.
{"title":"Enhanced DC and RF performance of an SOI-MESFET with dual intrinsic layers and a doped channel bottom","authors":"Seyed Mohammad Razavi , Toktam Aghaee","doi":"10.1016/j.ijoes.2025.101240","DOIUrl":"10.1016/j.ijoes.2025.101240","url":null,"abstract":"<div><div>In this paper, a proposed structure of SOI-MESFET with two intrinsic semiconductor layers at the top of the channel and an area with additional impurities in the channel bottom (IA-SOI) is presented. In addition to this structure, the transistor, which has only two intrinsic semiconductor layers at the top of the channel (I-SOI), is tested to determine the importance of the layer with more impurities in the channel bottom of IA-SOI. Some of the most important electrical parameters of the proposed transistors are studied and compared with those of the conventional structure (C-SOI). These parameters include drain current, electric field, breakdown voltage, gate-source capacitor, output resistance, maximum output power density and threshold voltage. The two intrinsic semiconductor layers of IA-SOI improve the breakdown voltage of this transistor by 45 % and reduce the gate-source capacitor by 18 % compared to those of the C-SOI. Also, the layer with additional impurities in the channel bottom of the proposed structure increases the drain current by 100 %. Simultaneous increase of drain current and breakdown voltage in IA-SOI significantly increases the maximum power density of this transistor compared to the conventional one. Comparing I-SOI with the conventional structure, it can be concluded that I-SOI increases the output resistance by 100 % compared to that in the C-SOI structure.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101240"},"PeriodicalIF":2.4,"publicationDate":"2025-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-12DOI: 10.1016/j.ijoes.2025.101239
Bin He , Zhuwei Lu , Ziming Xue , Weining Lei
The flow field distribution is important to the processing quality of array structures in electrochemical machining (ECM). To solve the problem of poor consistency of multiple rows of pits, a flow field optimization method was proposed to reduce the height of the cathode teeth and add the flow channel and transition region. The flow field simulation results showed that there was evaporation under the initial flow field, and the flow velocity in the processing area of multiple rows of pits gradually decreased. The flow of electrolyte in the optimized flow field was more concentrated, the flow velocity in the processing area was greater than that in the non-processing area between rows, and the flow velocity in multiple rows of pits was more uniform. The pit arrays of 6 rows × 10 columns were processed by using the initial and optimized flow field. The pit arrays processed with the optimized flow field are more consistent; the standard deviations (SD) of the depth, length, and width of pits are 3.87μm, 10.16μm and 12.02μm, respectively. In addition, the optimized flow field also helps to reduce stray corrosion. This research has certain reference value for solving the processing problem of the anvil part of the endoscopic stapler.
{"title":"Flow field optimization for electrochemical machining of pit arrays in multiple rows","authors":"Bin He , Zhuwei Lu , Ziming Xue , Weining Lei","doi":"10.1016/j.ijoes.2025.101239","DOIUrl":"10.1016/j.ijoes.2025.101239","url":null,"abstract":"<div><div>The flow field distribution is important to the processing quality of array structures in electrochemical machining (ECM). To solve the problem of poor consistency of multiple rows of pits, a flow field optimization method was proposed to reduce the height of the cathode teeth and add the flow channel and transition region. The flow field simulation results showed that there was evaporation under the initial flow field, and the flow velocity in the processing area of multiple rows of pits gradually decreased. The flow of electrolyte in the optimized flow field was more concentrated, the flow velocity in the processing area was greater than that in the non-processing area between rows, and the flow velocity in multiple rows of pits was more uniform. The pit arrays of 6 rows × 10 columns were processed by using the initial and optimized flow field. The pit arrays processed with the optimized flow field are more consistent; the standard deviations (SD) of the depth, length, and width of pits are 3.87μm, 10.16μm and 12.02μm, respectively. In addition, the optimized flow field also helps to reduce stray corrosion. This research has certain reference value for solving the processing problem of the anvil part of the endoscopic stapler.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101239"},"PeriodicalIF":2.4,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.ijoes.2025.101229
Haijun Zhan
Sports drug testing is crucial for protecting athlete health and upholding the integrity of fair competition. While chromatography coupled with mass spectrometry (MS) remains the gold standard in world anti-doping agency (WADA) accredited laboratories, its logistical and economic constraints limit the scope and frequency of testing, creating a significant detection gap. This gap highlights an urgent need for analytical platforms that are rapid, cost-effective, and adaptable for high-throughput screening and on-site testing. This review critically examines capillary electrophoresis coupled with electrochemical detection (CE-EC) as a powerful and versatile platform poised to fill this specific need. This review posits that CE-EC's primary role is not to replace the confirmatory power of MS, but to act as a vital complementary technology. This review provides a comprehensive analysis of technological advances that have enhanced CE-EC performance, including nanomaterial-modified electrodes and molecularly imprinted polymers for superior sensitivity, miniaturization into lab-on-a-chip formats for high-throughput analysis, and advanced detection modalities such as pulsed amperometric detection and capacitively coupled contactless conductivity detection. Concurrently, this review addresses the core challenges that have hindered its adoption, including the debate over sensitivity relative to MS, matrix effects in biological samples, and the need for robust, validated methods. By presenting evidence from recent literature, this review delineates the specific contexts in which CE-EC is a viable platform. Finally, this review explores future directions, focusing on portable, on-site CE-EC devices that could revolutionize anti-doping strategies by shifting the paradigm from centralized detection to widespread, real-time deterrence.
{"title":"Capillary electrophoresis with electrochemical detection: A promising platform for anti-doping analysis","authors":"Haijun Zhan","doi":"10.1016/j.ijoes.2025.101229","DOIUrl":"10.1016/j.ijoes.2025.101229","url":null,"abstract":"<div><div>Sports drug testing is crucial for protecting athlete health and upholding the integrity of fair competition. While chromatography coupled with mass spectrometry (MS) remains the gold standard in world anti-doping agency (WADA) accredited laboratories, its logistical and economic constraints limit the scope and frequency of testing, creating a significant detection gap. This gap highlights an urgent need for analytical platforms that are rapid, cost-effective, and adaptable for high-throughput screening and on-site testing. This review critically examines capillary electrophoresis coupled with electrochemical detection (CE-EC) as a powerful and versatile platform poised to fill this specific need. This review posits that CE-EC's primary role is not to replace the confirmatory power of MS, but to act as a vital complementary technology. This review provides a comprehensive analysis of technological advances that have enhanced CE-EC performance, including nanomaterial-modified electrodes and molecularly imprinted polymers for superior sensitivity, miniaturization into lab-on-a-chip formats for high-throughput analysis, and advanced detection modalities such as pulsed amperometric detection and capacitively coupled contactless conductivity detection. Concurrently, this review addresses the core challenges that have hindered its adoption, including the debate over sensitivity relative to MS, matrix effects in biological samples, and the need for robust, validated methods. By presenting evidence from recent literature, this review delineates the specific contexts in which CE-EC is a viable platform. Finally, this review explores future directions, focusing on portable, on-site CE-EC devices that could revolutionize anti-doping strategies by shifting the paradigm from centralized detection to widespread, real-time deterrence.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101229"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.ijoes.2025.101230
Jiantao Wang, Bochen Jiang
This study systematically investigates the corrosion behavior of DH36 steel under the combined influence of chloride (Cl⁻) and hydrogen (H⁺) ions, simulating marine splash zone environments. Electrochemical techniques—including potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS)—coupled with microstructural analyses (SEM and EDS) were employed to evaluate corrosion mechanisms in NaCl solutions (1–7.5 wt%) and in acidic solutions containing 3.5 wt% NaCl with HCl concentrations ranging from 0 to 0.6 mol/L. Results reveal that with increasing Cl− concentration, the corrosion potential decreases from − 519 mV to − 588 mV and the corrosion current density increases from 0.0137 mA/cm² to 0.0279 mA/cm², indicating accelerated corrosion rates. Notably, at > 5 wt% NaCl, pit density surges to 11,440 pits/mm² (7.5 wt%), while pit size expands by ∼ 80 %. In acidic Cl⁻-rich environments (HCl ≥ 0.4 mol/L), corrosion intensifies, and corrosion products become porous, facilitating longitudinal grooves and deep pits. EIS data confirm decreased polarization resistance (e.g., Rp drops from 4211 Ω·cm² to 2297 Ω·cm² in 7.5 wt% NaCl), and Warburg impedance emerges, signifying diffusion-controlled corrosion. The dominant mechanism involves electrochemical reactions where Cl⁻ and H⁺ act in concert to aggressively promote Fe dissolution via soluble complexes (e.g., [FeCl(OH)]⁻ad), while acidic conditions inhibit passivation. These findings highlight the critical vulnerability of DH36 steel in aggressive marine settings, providing essential insights for enhancing corrosion resistance in offshore structures.
{"title":"Investigation of the effect of chloride ions on the corrosion of DH36 steel in acidic solution","authors":"Jiantao Wang, Bochen Jiang","doi":"10.1016/j.ijoes.2025.101230","DOIUrl":"10.1016/j.ijoes.2025.101230","url":null,"abstract":"<div><div>This study systematically investigates the corrosion behavior of DH36 steel under the combined influence of chloride (Cl⁻) and hydrogen (H⁺) ions, simulating marine splash zone environments. Electrochemical techniques—including potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS)—coupled with microstructural analyses (SEM and EDS) were employed to evaluate corrosion mechanisms in NaCl solutions (1–7.5 wt%) and in acidic solutions containing 3.5 wt% NaCl with HCl concentrations ranging from 0 to 0.6 mol/L. Results reveal that with increasing Cl<sup>−</sup> concentration, the corrosion potential decreases from − 519 mV to − 588 mV and the corrosion current density increases from 0.0137 mA/cm² to 0.0279 mA/cm², indicating accelerated corrosion rates. Notably, at > 5 wt% NaCl, pit density surges to 11,440 pits/mm² (7.5 wt%), while pit size expands by ∼ 80 %. In acidic Cl⁻-rich environments (HCl ≥ 0.4 mol/L), corrosion intensifies, and corrosion products become porous, facilitating longitudinal grooves and deep pits. EIS data confirm decreased polarization resistance (e.g., R<sub>p</sub> drops from 4211 Ω·cm² to 2297 Ω·cm² in 7.5 wt% NaCl), and Warburg impedance emerges, signifying diffusion-controlled corrosion. The dominant mechanism involves electrochemical reactions where Cl⁻ and H⁺ act in concert to aggressively promote Fe dissolution via soluble complexes (e.g., [FeCl(OH)]⁻<sub>ad</sub>), while acidic conditions inhibit passivation. These findings highlight the critical vulnerability of DH36 steel in aggressive marine settings, providing essential insights for enhancing corrosion resistance in offshore structures.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"21 1","pages":"Article 101230"},"PeriodicalIF":2.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.ijoes.2025.101227
Yuvraj Maphrio Mao , Ramya K. , Somil Thakur , Rajnish Kaur Calay , Sanket Goel
In this study, an evaluation of textile-based cathodes and their surface modifications is conducted to enhance the performance of air-cathode MFCs. Among the tested materials, carbon cloth (CC) modified with Barium Titanate (BaTiO₃) demonstrated the highest power output of 9.81 µW/cm², outperforming both unmodified and other modified electrodes. Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed improved electron transfer and reduced charge transfer resistance, while nitrogen adsorption–desorption (BET) analysis revealed a high surface area and mesoporous structure for BaTiO₃, correlating strongly with its enhanced electrochemical activity. Structural and compositional analyses via X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) validated successful perovskite modification. Electrolyte analysis revealed a neutral pH of 7.04 and a chemical oxygen demand (COD) of 1500 mg/L before operation, indicating a suitable environment for microbial activity and energy harvesting. Repeatability analysis over 10 operational cycles showed exceptional consistency with CC/BaTiO₃ achieving 89.97 % repeatability, and all CC-based electrodes maintaining over 45 % stability of the peak power obtained during a 3-hour operational run. Scanning electron microscopy (SEM) revealed favorable surface morphology supporting enhanced electrochemical activity. These results establish CC/BaTiO₃ as a robust and high-performing cathode material, offering significant potential for scalable, efficient, and reliable air-cathode MFC applications. The work ahead may focus on integrating CC/BaTiO3 as the electrode materials into miniaturized Air-Cathode MFCs for real-world and real-time energy harvesting applications.
{"title":"Barium titanate-modified carbon cloth for high-performance air-cathode microbial fuel cells","authors":"Yuvraj Maphrio Mao , Ramya K. , Somil Thakur , Rajnish Kaur Calay , Sanket Goel","doi":"10.1016/j.ijoes.2025.101227","DOIUrl":"10.1016/j.ijoes.2025.101227","url":null,"abstract":"<div><div>In this study, an evaluation of textile-based cathodes and their surface modifications is conducted to enhance the performance of air-cathode MFCs. Among the tested materials, carbon cloth (CC) modified with Barium Titanate (BaTiO₃) demonstrated the highest power output of 9.81 µW/cm², outperforming both unmodified and other modified electrodes. Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed improved electron transfer and reduced charge transfer resistance, while nitrogen adsorption–desorption (BET) analysis revealed a high surface area and mesoporous structure for BaTiO₃, correlating strongly with its enhanced electrochemical activity. Structural and compositional analyses via X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) validated successful perovskite modification. Electrolyte analysis revealed a neutral pH of 7.04 and a chemical oxygen demand (COD) of 1500 mg/L before operation, indicating a suitable environment for microbial activity and energy harvesting. Repeatability analysis over 10 operational cycles showed exceptional consistency with CC/BaTiO₃ achieving 89.97 % repeatability, and all CC-based electrodes maintaining over 45 % stability of the peak power obtained during a 3-hour operational run. Scanning electron microscopy (SEM) revealed favorable surface morphology supporting enhanced electrochemical activity. These results establish CC/BaTiO₃ as a robust and high-performing cathode material, offering significant potential for scalable, efficient, and reliable air-cathode MFC applications. The work ahead may focus on integrating CC/BaTiO<sub>3</sub> as the electrode materials into miniaturized Air-Cathode MFCs for real-world and real-time energy harvesting applications.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101227"},"PeriodicalIF":2.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.ijoes.2025.101223
Basima A.A. Saleem , Amer Th. Al-Taee , Salim A. Mohammed
Given critical therapeutic role and formulation challenges for paclitaxel, the accurate quantification of PAC in pharmaceutical products and biological samples is of great importance. In this study, we developed a novel electrochemical sensor by electropolymerizing 3-nitro tyrosine on a gold electrode, followed by modification with tungsten carbamide (WC) nanoparticles to enhance conductivity and surface area. Scanning electron microscopy confirmed a uniform nanostructured coating with high electroactive surface roughness. The fabricated P3NLT/WC/AuE sensor exhibited a distinct oxidation signal at −1.13 mV, which shifted positively upon interaction with PAC, indicating a selective recognition process between the polymeric layer and the drug. Using differential pulse voltammetry, the sensor displayed a broad linear dynamic range (1.33E-09 mol.L−1 to 5.42E-06 mol.L−1) and an ultra-low detection limit of 1.20E-11 mol.L−1. The applicability of the developed platform was validated through the determination of PAC in commercial injection formulations, achieving recovery rates between 99.01 % and 101.02 %. These results highlight the P3NLT /WC/AuE sensor as a promising, sensitive, and selective analytical tool for pharmaceutical quality control and therapeutic drug monitoring of paclitaxel in clinical practice.
{"title":"Electrochemical determination of paclitaxel using a poly(3-nitro-L-tyrosine)/WC NPs modified gold electrode","authors":"Basima A.A. Saleem , Amer Th. Al-Taee , Salim A. Mohammed","doi":"10.1016/j.ijoes.2025.101223","DOIUrl":"10.1016/j.ijoes.2025.101223","url":null,"abstract":"<div><div>Given critical therapeutic role and formulation challenges for paclitaxel, the accurate quantification of PAC in pharmaceutical products and biological samples is of great importance. In this study, we developed a novel electrochemical sensor by electropolymerizing 3-nitro tyrosine on a gold electrode, followed by modification with tungsten carbamide (WC) nanoparticles to enhance conductivity and surface area. Scanning electron microscopy confirmed a uniform nanostructured coating with high electroactive surface roughness. The fabricated P3NLT/WC/AuE sensor exhibited a distinct oxidation signal at −1.13 mV, which shifted positively upon interaction with PAC, indicating a selective recognition process between the polymeric layer and the drug. Using differential pulse voltammetry, the sensor displayed a broad linear dynamic range (1.33E-09 mol.L<sup>−1</sup> to 5.42E-06 mol.L<sup>−1</sup>) and an ultra-low detection limit of 1.20E-11 mol.L<sup>−1</sup>. The applicability of the developed platform was validated through the determination of PAC in commercial injection formulations, achieving recovery rates between 99.01 % and 101.02 %. These results highlight the P3NLT /WC/AuE sensor as a promising, sensitive, and selective analytical tool for pharmaceutical quality control and therapeutic drug monitoring of paclitaxel in clinical practice.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101223"},"PeriodicalIF":2.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.ijoes.2025.101226
P. Ashtari, T. Gholizadeh
This research focused on the possibility of fabricating a gradient Ni/SiO2 nanocomposite coating on a St. 37 substrate using the electrodeposition method from a Watts bath. The effects of applied current density and nanoparticle (NP) concentration on the coatings' composition, microstructure, microhardness, and corrosion resistance were investigated. GDS and EDS analyses were used to quantify the NP concentration and evaluate the NP dispersion in the coating, respectively. Response Surface Methodology (RSM) was employed via Design-Expert software for process optimization. Following the determination of optimized parameters, a gradient coating was successfully produced under three distinct deposition conditions. The microstructure of the coatings was studied using XRD, and the mechanical and electrochemical properties were evaluated through microhardness measurements and potentiodynamic polarization tests, respectively. Findings confirmed the successful production of a gradient coating, with SiO2 content precisely controlled from 0.69 wt% at the interface to a maximum of 3.49 wt% at the surface. The incorporation of SiO2 NPs induced significant grain refinement, reducing the average crystallite size from 138 nm to 90 nm. This microstructural modification resulted in a corresponding increase in microhardness to 359 Hv. The corrosion current density decreases by up to 8.9 times compared to low-nanoparticle content layers.
{"title":"Electrodeposition of gradient Ni/SiO₂ nanocomposite coatings on St.37 steel: Microstructure, mechanical properties, and corrosion resistance","authors":"P. Ashtari, T. Gholizadeh","doi":"10.1016/j.ijoes.2025.101226","DOIUrl":"10.1016/j.ijoes.2025.101226","url":null,"abstract":"<div><div>This research focused on the possibility of fabricating a gradient Ni/SiO<sub>2</sub> nanocomposite coating on a St. 37 substrate using the electrodeposition method from a Watts bath. The effects of applied current density and nanoparticle (NP) concentration on the coatings' composition, microstructure, microhardness, and corrosion resistance were investigated. GDS and EDS analyses were used to quantify the NP concentration and evaluate the NP dispersion in the coating, respectively. Response Surface Methodology (RSM) was employed via Design-Expert software for process optimization. Following the determination of optimized parameters, a gradient coating was successfully produced under three distinct deposition conditions. The microstructure of the coatings was studied using XRD, and the mechanical and electrochemical properties were evaluated through microhardness measurements and potentiodynamic polarization tests, respectively. Findings confirmed the successful production of a gradient coating, with SiO<sub>2</sub> content precisely controlled from 0.69 wt% at the interface to a maximum of 3.49 wt% at the surface. The incorporation of SiO<sub>2</sub> NPs induced significant grain refinement, reducing the average crystallite size from 138 nm to 90 nm. This microstructural modification resulted in a corresponding increase in microhardness to 359 Hv. The corrosion current density decreases by up to 8.9 times compared to low-nanoparticle content layers.</div></div>","PeriodicalId":13872,"journal":{"name":"International Journal of Electrochemical Science","volume":"20 12","pages":"Article 101226"},"PeriodicalIF":2.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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