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Atrazine, a human-made herbicide, is infamous for its endocrine-disrupting properties, with adverse consequences on the immune, reproductive, and nervous systems. Consequently, effective recognition of atrazine in various environments, such as water, is critically important. This work presents a precise and efficient method for detecting atrazine across various environments, utilizing a well-established electrochemical technique. A metal organic framework (MOF) ZIF-67 has been synthesized and employed as a catalyst for the electrochemical detection of the triazine herbicide atrazine. Structural, morphological, and chemical analyses were conducted to evaluate the sensing material and to elucidate the interactions between the sensor and the analyte. The ZIF-67 was then integrated on the surface of the working electrode (carbon paste electrode (CPE)) to form a ZIF-67 modified-CPE (ZIF-67/MCPE). The ZIF-67/MCPE was utilized to detect atrazine by electrochemical techniques including differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The sensor demonstrated excellent sensitivity and was effective in detecting atrazine. The modified sensor demonstrated a lower limit of detection (LLOD) of 3.7 μM within a linear concentration range of 4–44 μM and exhibited a strong linear correlation efficiency of 0.97. Computational results corroborated the experimental findings, revealing that the combination of ZIF-67 with atrazine forms minor triangular structures and exhibits enhanced dynamics compared to the pristine MOF. This improvement in the crystallinity of the ZIF-67 MOF with atrazine is attributed to the negative binding energy and reduced energy gap at the interface between the MOF and atrazine. Additionally, the sensor's practical application was evaluated by testing it on sewage water and fresh liquid milk. The sensor demonstrated an exceptional ability to detect atrazine, with a recovery rate ranging from 96% to 99%. This approach holds promise for developing electrochemical or solid-state devices for real-time atrazine monitoring. [ABSTRACT FROM AUTHOR]

Upadacitinib (UPA) is a selective and reversible oral Janus kinase (JAK) 1 inhibitor and is of great importance in treating inflammatory bowel disease (Zheng et al., Int Immunopharmacol 126:111229, 2024; Foy et al., JAAD Case Rep 42:20–22, 2023). Although there are limitations to the effectiveness of UPA, it has received positive responses in clinical trials and is approved for the treatment of atopy dermatitis (AD) (Li et al., Int Immunopharmacol 125:111193, 2023). In this study, a nanoparticle-doped molecularly imprinted polymer (MIP)-based electrochemical sensor was developed for sensitive and selective detection of UPA. The developed sensor was designed as a thin film layer using the photopolymerization method on the surface of the prepared nanoparticle-doped polymerization solution glassy carbon electrode (GCE). Various nanoparticles, such as multi-walled carbon nanotube, titanium dioxide, oxide, and zinc oxide (ZnO) nanoparticles, were the most suitable for UPA. Surface characterization of the developed sensor was done by scanning electron microscopy (SEM), and electrochemical characterization was done by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The quantitative analysis of UPA was performed in 5.0 mM [Fe (CN)6]3−/4− solution using the differential pulse voltammetry (DPV) technique. Under optimum conditions, the calibration range was between 0.1 and 1 pM. The limit of detection (LOD) and limit of quantification (LOQ) were calculated as 0.005 pM and 0.017 pM, respectively. The sensor's accuracy was proven by performing a recovery study in serum. The sensor's selectivity was also evaluated using common interfering substances such as KNO3, CaCl2, Na2SO4, uric acid, ascorbic acid, dopamine, and paracetamol. According to the results obtained, the performance of the designed sensor was found to be quite sensitive and selective in determining UPA. The developed UPA-ZnO/3-APBA@MIP-GCE sensor showed high sensitivity and selectivity towards UPA. In addition, the selectivity, the most important feature of the MIP-based sensor, was confirmed by imprinting factor (IF) calculations using tofacitinib (TOF) and ruxolitinib (RUX). The sensor's unique selectivity is demonstrated by its successful performance even in the presence of UPA impurities. [ABSTRACT FROM AUTHOR]

Rapid virus identification is crucial for preventing outbreaks. The COVID-19 pandemic has highlighted the critical nature of rapid virus detection. Here, we designed a label-free electrochemical biosensor modified with gold nanoparticles (AuNPs) to detect IgG antibodies from human serum, enabling rapid point-of-care diagnostics. AuNPs were synthesized and characterized. A multivariate optimization was carried out to determine the optimal condition for functionalizing AuNPs with anti-IgG. Subsequently, using a glassy carbon electrode (GCE), a modified AuNPs/GCE electrochemical biosensor was developed for IgG detection. The results indicated that AuNPs displayed a spherical morphology with a size distribution of 19.54 nm. Additionally, the zeta potential was recorded at −7.84 mV. Central composite design (CCD) analysis determined the optimal conditions for functionalizing AuNPs to be an anti-IgG concentration of 320 µg mL−1, a temperature of 25 °C, and pH of 7.4. The characterization study confirmed the successful synthesis and functionalization of AuNPs. Through electrochemical impedance spectroscopy measurement, the biosensor demonstrated a limit of detection (LOD) of 0.2 ng mL−1 and limit of quantification (LOQ) of 0.8 ng mL−1. Furthermore, tests in real samples showed the interaction between IgG antibodies in serum samples and AuNPs/GCE, confirming the biosensor's ability to detect and quantify IgG in clinical samples. [ABSTRACT FROM AUTHOR]

Metal complexes based on mono(arylhydrazino)acenaphthenones (Ar-mhan) are extremely rare. In this work, synthetic routes for previously unknown rhodium complexes containing 2-(pyridin-2-yl)hydrazino acenaphthene-1-one (Py-mhan) are proposed. The interaction of RhCl3·3H2O with Py-mhan, depending on the conditions, led to two anionic complexes: (HPy-mhan)+[Rh(Py-mhan)Cl3] (1) and (NBu4)[Rh(Py-mhan)Cl3] (2). The complexes were characterized using X-ray diffraction analysis, elemental analysis, and IR- and 1H NMR-spectroscopies. The electrochemical properties of complex 2 were investigated using cyclic voltammetry. Complex 2 demonstrated irreversible reduction at −0.69 V (vs. Ag/AgCl), which is accompanied by the elimination of chloride ligands to give a Rh(I) complex namely [Rh(Py-mhan)(CH3CN)] (3). Complex 3 was isolated by electroreduction of complex 2 on a carbon glass electrode and characterized by EDS analysis, CHN analysis, 1H NMR spectroscopy and cyclic voltammetry. For complexes 2 and 3, reversible reduction processes localized on Py-mhan were found. To confirm the nature of electrochemical transformations for complexes 2 and 3 in solution, quantum chemical calculations were performed. [ABSTRACT FROM AUTHOR]

L-Cysteine is a semi-essential and proteinogenic amino acid, with the formula HO2CCH (NH2) CH2SH. L-cysteine is mostly found in protein-rich foods. In this study, catalysts consisting of cobalt (Co) supported on carbon nanotubes (CNTs) were prepared using the sodium borohydride (NaBH4) reduction method. These catalysts were characterized by means of energy-dispersive x-ray (EDX) with scanning electron microscopy (SEM), temperature-programmed reduction (TPR), and temperature-programmed oxidation (TPO) techniques. Characterization results confirmed the successful preparation of the desired catalyst. After preparing the Co/CNT catalysts, a highly efficient and sensitive electrochemical sensor was developed using a glassy carbon electrode (GCE) modified with the Co/CNT catalysts. The electrochemical behavior of the bare GCE and Co/CNT-modified GCE electrodes was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) in 0.1 M phosphate buffer solution (PBS) + L-cysteine. Electrochemical results showed that the Co/CNT-modified GCE electrode exhibited high sensitivity and selectivity compared to the bare GCE, with sensitivity of 0.0046 µA/µM, limit of detection of 0.2 µM, and limit of quantification of 0.6 µM. Furthermore, this electrode showed higher sensitivity values than those reported in the literature. Further interference studies were performed using CV and EIS to investigate interfering species in the serum environment, such as D-glucose, uric acid, L-tyrosine, and L-tryptophan. In conclusion, the results suggest that the Co/CNT-modified GCE electrode is a promising catalyst for the sensitive detection of L-cysteine. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) are considered one of the front-runner energy storage devices for future electronic and automobile device applications. Even though their high-power densities, fast charge/discharge, and long cycling stabilities make them promising for future applications, their charge-discharge takes place below 1 Hz, a major issue for using them as capacitors for line filtering applications. Therefore, developing ultrafast electrochemical supercapacitors with alternating current (AC) line filtering functions has gained research attention to replace conventional aluminum electrolytic capacitors (AEC). Most available SCs possess resistive features rather than capacitive at 120 Hz because of the electrode geometry and configurations, which is a bottleneck in the research of line-filtering SCs. Addressing this challenge could be possible by developing novel electrode materials using hybrid nanostructures to meet the critical requirements for line filtering functions. This mini-review focuses on the advancement and challenges of carbon nanostructure-based electrode materials for AC line filtering applications and the future directions of this growing research area. [ABSTRACT FROM AUTHOR]

Electrochemical energy storage is one of the effective ways that can address the mentioned issues as alternative energy/power produced through solar or windmills can effectively be stored for continuous usage. Hybrid/Asymmetric supercapacitors can deliver a significant amount of power density as well as increased energy density with better rate capability and longer lifespan. The fluffy carbonized hexagonal KCoPO4 synthesized via a simple sol‐gel method accompanied by calcination has delivered high capacitance and longer cyclibility as a positive electrode in aqueous asymmetric supercapacitors. The fluffy carbonized hexagonal KCoPO4 exhibited a specific capacitance equal to 725 F/g at 0.5 A/g current density with excellent cyclic stability. The predominant intercalative pseudocapacitive charge storage behavior seems to be the reason behind the high capacitance of the electrode due to the active involvement of Co2+/3+ redox couple mediate charge storage as intercalative (inner) and capacitive, (outer) surface charges storage on the electrode were close to 37 % and 63 % respectively. Aqueous Asymmetric supercapacitor mode with KCoPO4 being a positive electrode and activated carbon being a negative electrode (KCoPO4//AC) was designed to address its performance in 2 M KOH aqueous electrolyte. The fabricated device in AASc mode (AC//KCoPO4) achieved the highest energy density close to 121.1 Wh/kg with a high power density of 6945 W/kg in the potential window of 1.5 V in 2 M KOH electrolyte. [ABSTRACT FROM AUTHOR]

This work aims to allocate coffee grounds waste to the production of biochar from pyrolysis under different temperatures (350 °C and 500 °C), to add value to it. The resulting materials were characterized by immediate, elemental, thermogravimetric analysis, SEM, FT‐IR, XRD and Raman spectroscopy. Additionally, the need to activate the biochar produced for the desired use was evaluated. The obtained biochars were applied in electroanalysis in the manufacture of modified carbon paste electrodes. This choice was made due to the possibility of reaching a high sensitivity towards the determination of Cu2+ ions. The differential pulse adsorptive anodic stripping voltammetry technique was applied to perform the Cu2+ determination and, in this case, several parameters were optimized, including biochar' percentage, pH of pre‐accumulation step and reduction/stripping step, pre‐accumulation time, potential and time of reduction of adsorbed‐Cu2+. From this, the proposed modified electrode showed a linear voltammetric response towards Cu2+ in the range of 66.1 to 3997.3 ppb, with a limit of detection of 31.8 ppb, in addition to having been satisfactorily applied in the analysis of water samples (recoveries close to 100 %). Thus, demonstrating the potential for reuse of discarded coffee grounds for the preparation of activated biochar with outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

The current work reports a novel approach for the development of an electrochemical sensor based on Ni and Mg-co-doped ZnO nanoparticles (ZNMO) to detect and quantify cysteamine (CA). The chemical co-precipitation strategy was used to synthesize zinc oxide co-doped with magnesium and nickel which can be used as a catalyst material. FTIR, XRD, XPS, BET and SEM-EDX examinations were used to confirm the produced material. The surface of the glassy carbon electrode (GCE) was modified with ZNMO nanoparticles, resulting in a remarkable improvement in the surface area of the electrodes which in turn improved the response for CA compared to previously reported studies. This enhancement can be attributed to the superior catalytic activity of the material in electro-oxidizing CA. The electrochemical studies were carried out using the analytical techniques like cyclic voltammetry and differential pulse voltammetry using 0.1 M phosphate buffer saline as a supporting medium. This fabricated sensor, ZNMO nanoparticles modified GCE (ZNMO/GCE) has shown superior sensing characteristics, including high selectivity, sensitivity, stability, and repeatability, for the identification and quantification of CA. The sensor successfully confirmed the diffusion-controlled electrode technique. It exhibited the widest linear range, spanning from 1 nM to 2500 μM, which is the most impressive result ever reported. The limit of detection (LOD) was determined to be 0.75 nM. Additionally, at the developed sensor, a real-sample analysis was conducted using biological fluids. Hence, the fabricated ZNMO/GCE showed excellent electrocatalytic performance for CA sensing, making it suitable for real-time monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

Thermal treatments are commonly used to improve electrode kinetics in vanadium redox flow batteries (VRFB). The impact of the widely adopted thermal treatment—400 °C for least 24 hours—was investigated on polyacrylonitrile (PAN)‐based continuous carbon filaments (tows) and compared to PAN‐based graphite felts. Surface properties were assessed with scanning electron microscopy (SEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS) and wettability measurements. The electrode activity was investigated via electrochemical impedance spectroscopy (EIS). Charge‐transfer resistances and the constant phase element parameters related to the electric double layer were determined, revealing a correlation between enhanced electrode activity and increased double layer across all electrodes. An 8‐hour 400 °C thermal treatment was sufficient to improve electrode activity for tows, whereas felts required longer durations, up to 24 hours, attributed to differences in the carbonization process employed for each material, with the tows undergoing continuous processing and the felts following a batch process. Three‐electrode half‐cell EIS measurements were conducted to elucidate positive and negative electrode contributions. Activated continuous carbon filament electrodes exhibited consistent electrode activities in both the catholyte (VO2+/VO2+) and anolyte (V3+/V2+), whereas the electrochemical activity of felts was limited by the electrode deactivation in the anolyte. [ABSTRACT FROM AUTHOR]

In the present work, the incorporation of hydrophobic porphyrins in organic polymers through electrochemically induced polymerization of monomers on conventional electrodes and the preliminary investigations on the electrocatalytic activity of these modified electrodes are explained. Electropolymerized porphyrins show better activity than organic polymers of N‐isopropylacrylamide, triethylene glycol methyl ether methacrylate, and glycerol 1,3‐diglycerolate diacrylate for nitrite oxidation due to the presence of cobalt metal ion. Among the porphyrins investigated, electropolymerized cobalt tetra‐2‐thienylporphyrin requires the least overpotential, due to ease of polymerization and better coating on glassy carbon electrode compared with that of cobalt tetraphenylporphyrin and cobalt tetra‐3‐thienylporphyrin. On encapsulating these porphyrins in organic polymers, improved current and lower overpotential are noticed. [ABSTRACT FROM AUTHOR]

Metal sulfide-based composites have become increasingly common as materials used for electrodes in supercapacitors because of their excellent conductivity, electrochemical activity, and redox capacity. This study synthesized a composite of NiFeS@MoS2@rGO nanostructure using a simple hydrothermal approach. The synthesized nanocomposite consisted of the composite of nickel sulfide and iron sulfide doped with MoS2@rGO. A three-electrode cell is employed to investigate the electrochemical properties of the NiFeS@MoS2@rGO electrode. The results demonstrated an optimal specific capacitance of 3188 F/g at 1.4 A/g in a 1 M KOH electrolyte. Furthermore, a supercapattery is designed utilizing NiFeS@MoS2@rGO//AC as the positive electrode and activated carbon (AC) as the negative electrode materials. The resulting supercapattery is designed at a cell voltage of 1.6 V, achieving a specific capacity value of 189 C/g at 1.4 A/g. It also demonstrated an excellent energy density of 55 Wh/kg with an enhanced power density of 3800 W/kg. Furthermore, the hybrid device demonstrated remarkable stability with a cycling stability of 95% over 30,000 charge–discharge cycles at a current density of 1.4 A/g. The supercapattery, which has excellent energy storage capabilities, is used as a power source for operating different portable electronic devices. [ABSTRACT FROM AUTHOR]

In the current study, we synthesized copper oxide nanostructures (CuO NSs) via a facile hydrothermal procedure. We characterized them with the help of scanning electron microscopy (SEM) and X-ray diffractometry (XRD). SEM study revealed that CuO NSs inherited nanoneedles-based flowering geometry with a porous nature, while XRD proved the crystalline nature of these NSs. When deposited on a glassy carbon electrode (GCE), these nanostructures are displayed as a sensitive sulfite detection tool in the sample matrix. The results showed that sodium hydroxide, with pH 10.0, was the best-supporting electrolyte among all electrolytes studied. The as-prepared sulfite sensor performed well in a linear working range of 10–100 µM sulfite with the low detection limit (LOD) of the amperometry technique used to evaluate the analytical performance of the electrode, such as a limit of 1.12 µM. The developed sensor was highly stable and reproducible, showing a relative standard deviation of 2.17% for 10 cycles. The sensor also exhibited more selectivity for sulfite in the presence of probable interfering species, including cyanide, sulfate, chloride, and nitrate. The findings further proved the CuO/GCE-Nafion-based sensor as a sensitive diagnostic tool for quantifying or monitoring health-hazardous sulfite in the environmental sample matrices. [ABSTRACT FROM AUTHOR]

In this study, a highly sensitive electrochemical sensor for the detection of bisphenol A (BPA) was developed by modifying a screen-printed carbon electrode (SPCE) with silver nanoparticles (AgNPs) and graphene oxide (GO) composites. The electrochemical properties of the modified electrode interface were meticulously investigated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy, employing 1.0 mM [Fe(CN)6]3–/[Fe(CN)6]4– as a redox probe. The findings demonstrate that the AgNPs/GO/SPCE composite exhibits superior electrical conductivity and facilitates rapid electron transfer compared to both GO/SPCE and SPCE alone. The electrochemical behavior of BPA on the AgNPs/GO/SPCE electrode was comprehensively studied using CV, revealing exceptional electrocatalytic properties for BPA oxidation. To assess the analytical performance, differential pulse voltammetry was employed. Results unequivocally show a significant improvement in the electrochemical responses when using AgNPs/GO/SPCE. Calibration curves exhibited linear ranges of 0.25–2.19 μM with a remarkable limit of detection of 0.046 μM for BPA. Furthermore, the established method was applied for the determination of BPA in plastic products, achieving satisfactory reproducibility and recovery. This novel AgNPs/GO/SPCE-based sensor holds promise for the sensitive and reliable detection of BPA in various environmental and industrial applications. [ABSTRACT FROM AUTHOR]

Thallium (Tl), a heavy metal, has potentially harmful effects on human health due to its extreme toxicity. The determination of Tl is critical, and thus, there is a need for the development of electrochemical sensors that can swiftly identify its presence in the environment. A one-step hydrothermal synthesis of Prussian blue (PB) was utilized to adsorb thallium and electrochemically activate PB. The structure and morphology of PB were characterized through a scanning electron microscope, X-ray energy spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The PB-modified electrode's determination performance was optimized using the square wave voltammetry method. This included the optimization of support electrolyte, pH, deposition potential, and deposition time. Under optimal experimental conditions, the electrode demonstrated a favorable electrochemical response to thallium concentrations between 10 and 500 μg/L, with a detection limit of 1.94 μg/L. In summary, this sensor's outcomes are satisfactory and enhance the utility of PB nanomaterials in electrochemically detecting the heavy metal Tl. [ABSTRACT FROM AUTHOR]

Water pollution by metals is increasing. An electrode material, copper hexacyanoferrate (CuHCF), for capacitive deionization (CDI) to remove Co2+ from wastewater was developed. The asymmetric electrode structure of the CDI overcomes the limitations of traditional activated carbon electrodes (low ion removal capacity, ion removal rate, and charge efficiency). The specific capacitance of the CuHCF electrode (216.7 F g−1) at 1 mV s−1 was higher than that of a traditional electrode (92.0 F g−1), and its deionization capacity was 156.85 mg g−1 in 50 mg L−1 aqueous Co2+ (charge efficiency = 68.4%). CuHCF is a high-performance electrode material for wastewater remediation. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor for the highly sensitive and selective determination of dopamine was developed, based on the use of a glassy carbon electrode modified with cobalt(II) polymer. Both electrochemical and morphological characterizations were investigated. Square wave voltammetry (SWV) was used for the determination of dopamine. From the SWV results obtained on the modified electrode under the optimized conditions, the successive addition of dopamine increased the anodic peak current. The results obtained show a linear response of the electrode modified with Co(II) polymer in a wide concentration range. Each concentration decade is characterized by a new calibration plot with a corresponding mathematical expression. The highest sensitivity (13.182) was obtained for the lowest concentration range, and the detection limit of 0.03 µM, calculated based on the 3 × sb/m criterion, indicates a very high sensitivity and great application potential. When analyzing a real sample, the modified electrode showed good electroanalytical activities in terms of oxidation of dopamine, good anti-interference ability, stability, reproducibility, and potential applicability in commercial pharmaceutical samples. [ABSTRACT FROM AUTHOR]

Endosulfan is an organochlorine pesticide widely used in agriculture to protect crops such as cotton, soybeans, coffee, tea, cereals, fruits, vegetables, and grains from pests. However, exposure to low concentrations of endosulfan causes harmful effects on humans' health. Therefore, the determination of endosulfan in food samples by a fast, simple, and cost-effective method is pivotal. In this study, an electrochemical sensor based on a polyaniline/Fe-ZnO-modified glassy carbon electrode (PANI/Fe-ZnO/GCE) was developed for the determination of endosulfan in vegetables. The synthesized nanomaterials were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). PANI/Fe-ZnO/GCE showed remarkable electrocatalytic activity for the determination of endosulfan in vegetables. It also exhibited a good linear response to endosulfan concentrations ranging from 1 to 400 µM. The method displayed a low detection limit (LOD) of 0.003 µM. The sensor showed good selectivity, long-term stability, good repeatability, and within-lab reproducibility. It was also applied for the determination of endosulfan in tomatoes and potatoes, with acceptable recoveries ranging from 87.00 to 96.80%. Graphical illustration of PANI/Fe-ZnO modified glassy carbon electrode for endosulfan determination in vegetables [ABSTRACT FROM AUTHOR]

The work reported herein describes the synthesis of a 3D material UiO-66(Zr)-NH-OC-MWCNT by combining a synthesized metal–organic framework UiO-66(Zr)-NH2 and a carboxy functionalized multi-walled carbon nanotube MWCNT-COOH via an amide linkage and demonstrated its application for simultaneous electrochemical determination of two benzimidazole fungicides-carbendazim and thiabendazole. Different analytical techniques like Fourier transform infrared spectroscopy, X-ray diffraction analysis, Brunauer–Emmett–Teller analysis, and Field emission scanning electron microscopy were employed to characterize all the synthesized materials. The electrochemical characterization of the fabricated electrode was carried out using cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetry and differential pulse voltammetry techniques have been used for the electroanalysis of carbendazim and thiabendazole. A limit of detection of 0.077 µM and 0.557 µM, respectively, have been obtained in the calibration range of 0.1 to 40 µM for carbendazim and 1 to 40 µM for thiabendazole, after optimization of several parameters which are susceptible to the sensitivity and selectivity of the developed sensor. Furthermore, with satisfactory results from the study of interferences, repeatability, and reproducibility, the proposed electrochemical sensor was successfully applied for analysis of carbendazim and thiabendazole in real samples. [ABSTRACT FROM AUTHOR]

This work studies gold nanoparticle (AuNP) nucleation and growth mechanism from deep eutectic solvent (DES)-based choline chloride and glycerol (glyceline) onto glassy carbon electrode (GCE) and its application for DNA biosensor. Investigation of the current density transients indicated that the AuNPs were formed by the simultaneous presence of Au diffusion-controlled 3D nucleation and growth and residual water reaction over the Au nuclei growing surfaces. The AuNP structure was characterized by the field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. AuNPs were used to fabricate electrochemical DNA sensor. The hybridization was monitored by cyclic voltammetry and electrochemical impedance spectroscopy measurement using potassium ferri/ferrocyanide redox probes F e (C N) 6 3 - / 4 - as the indicator probe. Results show that the biosensor exhibited a linear correlation to the logarithm of the target DNA concentration ranged from 1.10−14 M to 1.10−9 M, and the limit of detection was 1.10−14 M. Furthermore, the findings indicate that the prepared electrode exhibited excellent reproducibility and long-term stability when applied for determining M. tuberculosis samples. [ABSTRACT FROM AUTHOR]

We report the comparison of multiple acetylene black (AB) rigid carbon composites for electrochemical purposes exploring several binders, including one (polyurethane) from a renewable source of castor oil. The acetylene black–based composites presented less roughness and increased surface homogeneity evinced by AFM and SEM images within the micrometer range. Contact angle analysis and Raman spectra confirmed a high degree of surface functionalization associated with structural defects on AB even when the base conductive material is associated with a non-conductive binder. The acetylene black-castor oil electrode presented superior performance (lower resistance to charge transfer and increased peak currents) when compared to its graphite counterparts regardless of the mechanical activation. The proposed electrode presented an excellent electrochemical performance in analyzing contaminants of emerging concern when compared to glassy carbon electrodes. The sustainable aspect of this work is evinced considering the room temperature synthesis, low cost of the AB, and renewable castor oil binder source. [ABSTRACT FROM AUTHOR]

This study presents a novel sensor for the detection of levodopa (LD) utilizing a glassy carbon electrode modified with a TiO2/MWCNT nanocomposite. Structural analysis confirmed the suitability of the nanocomposite for sensor fabrication, revealing enhancements in effective surface area and sensitivity. Characterization studies employing SEM, EDX, and FT-IR analyses provided insights into the composition and morphology of the modified electrode. The sensor exhibited exceptional performance metrics, including a wide linear detection range (19.6–545 µM), low detection limit (2.51 µM), high repeatability (78.1%), and remarkable average recovery rates in real samples (99.86%). Minimal interference from interfering species further demonstrated its practical utility. Moreover, the sensor's direct applicability in diverse sample matrices, without the need for sample separation, highlighted its versatility and convenience. Comparative analysis revealed the sensor's performance to be comparable to established methods, offering a cost-effective and streamlined approach to LD measurement. Overall, the modified glassy carbon electrode with TiO2/MWCNT nanocomposite presents a clear, suitable, and stable electrocatalytic response, promising significant advancements in biosensing technology for LD detection. [ABSTRACT FROM AUTHOR]

Development of efficient, low‐cost, robust, and structure tunability electrocatalysts for hydrogen evolution reaction (HER) is one of the main subjects of present study in renewable energies. In this work, two new cuprous iodide coordination polymers (Cu‐CPs) containing bisbenzimidazole‐derived ligand, namely, {[Cu2(L1)(μ2‐I)2]·DMF}n (1) and {[Cu(L2)0.5(μ2‐I)]·DMF} (2) (L1 = (2,2′‐(1,3‐propanediyl)‐6,6′‐bis(3‐methylpyridine)bis‐1,3‐benzimidazole); L2 = (2,2′‐(1,4‐butanediyl)‐7,7′‐bis(3‐methylpyridine)bis‐1,3‐benzimidazole); DMF = dimethyl formamide), were prepared under solvothermal conditions and structurally characterized. Single‐crystal structural analysis showed that although two Cu‐CPs have a one‐dimensional (1D) chain backbone structure, the coordination environment of cuprous is different. It is found that different coordination modes of ligands L1 and L2 lead to different coordination environments of central ions in two cuprous CPs. Electrocatalytic HER of modified electrodes (CP‐1~2/glassy carbon electrode [GCE]) prepared by coating the mixed solution of acetylene black, CPs 1–2, and Nafion on the surface of GCE was investigated in 0.5 M H2SO4 electrolyte. The HER measurements show that the overpotential η10293K of CP‐1~2/GCE positively shifted 113 and 74 mV compared with bare GCE (blank electrode, −930 mV), and the Tafel slope of bare/GCE and CP‐1~2/GCE were 298, 101, and 138 mV dec−1, respectively. The results indicate that CP‐1~2/GCE could effectively catalyze and accelerate the HER behavior, with electrocatalytic activity order being CP‐1/GCE > CP‐2/GCE > bare/GCE. The higher HER activity of the CP‐1/GCE can be attributed to that the coordination deformability of cuprous ion in CP 1 is greater. Furthermore, the recognition performance of CP‐1~2/GCE for glucose was further studied by chronoamperometry in 0.1 M NaOH. The two sensors can detect glucose in a linear range from 1 μM to 4 mM with sensitivities of 13.736 and 18.945 μA mM−1, and also revealed long‐term stability and good selectivity. These results indicate that cuprous CPs deserve further investigation as potential electrocatalyst candidates. [ABSTRACT FROM AUTHOR]

Development of high capacity and long cycle life electrode materials is essential to improving energy storage capacity in electrochemical rechargeable devices. In order to be commercially viable, the synthesis of these materials must be straightforward, cost-effective, and ideally a single-step process. We present a binder-free synthesis method for nickel phosphate hydrate (NiPH) and nickel molybdenum phosphate hydrate (NiMoPH) on nickel foam via a simple hydrothermal process. X-ray diffraction (XRD) patterns confirmed the formation of NiPH and NiMoPH phases, while X-ray photoelectron spectroscopy (XPS) verified the presence of nickel (Ni), molybdenum (Mo), phosphorus (P), and oxygen (O) in the composite. Scanning electron microscopy (FE-SEM) revealed the formation of micro-flowers with plate-like structures in NiPH, which transformed into hexagonal rod-like structures upon the introduction of molybdenum in NiPH. This morphological and phase modification increased the charge storage capacity from 1441 mF/cm2 (NiPH) to 2945 mF/cm2 (NiMoPH) at 20 mA/cm2. The NiMoPH electrode demonstrated excellent capacitance retention of 91.8 % over 10,000 cycles. Additionally, asymmetric supercapacitor (ASS) devices were fabricated using NiPH and NiMoPH as positive electrodes and activated carbon (AC) as the negative electrode. The NiPH//AC and NiMoPH//AC configurations exhibited energy densities of 0.086 and 0.201 mWh/cm2, respectively, with the NiMoPH//AC device maintaining about 90 % capacitance retention over 15,000 cycles. This study demonstrates the potential of incorporating conductive transition metals to enhance electrode material performance in energy storage applications. Hydrothermally synthesized nickel phosphate hydrate (NiPH) and nickel molybdenum phosphate hydrate (NiMoPH) electrode materials for energy storage devices have been reported. The transformation of NiPH microplates into hexagonal rods upon the addition of molybdenum was observed. This structural modification and improved conductivity, induced by the inclusion of molybdenum, enhances the electrochemical energy storage performance of the electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

Activated carbon derived from biomass offers several advantages, including high surface area, customizable pore sizes, abundance, resilience across temperatures, and cost-effectiveness. This study focuses on exploring the potential of palm shell as a renewable alternative for supercapacitor electrode materials. Specifically, it investigates the utilization of a gel composed of NaOH and PVA for activating carbon. Here, palm shell undergoes chemical activation, and its resulting activated carbon's structural and physicochemical properties are comprehensively examined using XRD, FTIR, and BET measurements. The investigation delves into the electrochemical properties using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy of electrodes fabricated from chemically activated carbon derived from palm shells. The activated carbon enhanced a surface area of 216.062 m2 g−1 and a pore volume of 0.1468 cm3 g−1, and it is produced through the innovative approach of gel-based activation. This research highlights the potential of palm shell-derived activated carbon as a viable, sustainable, and efficient material for supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

Monomers: gentian violet (GV), brilliant green (BG), aniline, and methyl violet (MV), as well as their copolymers, were electropolymerized and used to modify glassy carbon electrode (GCE) by enhancing the sensitivity of the electrode. This is due to their special characteristics of sensing ability of the electropolymerized polymers. The electropolymerization and characterization of these monomers and their copolymers were done using cyclic voltammetry (CV) on GCE as a working electrode against Ag/AgCl reference electrode and platinum wire as the counter electrode. The copolymers showed higher current peaks than their corresponding homopolymers. The electrochemical characterization of these polymers and copolymers was studied by scan rate effect each between 10 and 300 mV/s and pH effect between 1.56 and 5.30. After being modified by the copolymers: poly(BG-GV) and poly(BG-MV), the modified GCE showed good results in resolving the peaks of ascorbic acid and uric acid which otherwise showed an overlapped broad peak on bare GCE. The CV in bare GCE was scanned at different scan rates of 4 mM K3[Fe(CN)6] in 1 M KNO3 solution. The square root of scan rate dependence of peak current was plotted and the Randles–Sevcik equation was applied to determine the diffusion coefficient of Fe(CN)63− ion and which was 1.13 × 10–14 cm2/s. This was used to determine the area of the modified electrode after running the CV of 4 mM K3[Fe(CN)6] in 1 M KNO3 at different scan rates. Therefore, the electrochemical polymerization of organic dye polymers was able to increase the sensitivity of the electrode by increasing its area. [ABSTRACT FROM AUTHOR]

A novel approach was employed to craft innovative carbon-paste electrodes using cerium(IV) oxide (CeO2)-doped clay, aiming to modify graphite electrodes. The introduction of Ce involved the adsorption of Ce3+ ions onto an activated carbon (AC) clay mixture, showcasing an impressive adsorption capacity of 40.0 mg g−1, which surpasses that of clay alone. This step was undertaken to enhance the conductivity of raw clay and increase its electrochemical surface area. Sintering clay-CeO2 at 1000 °C resulted in the maximum electrochemical area when utilized as a 10 wt% dopant for graphite electrodes. Heavy metal ion analysis (HMI) involving Cd2+, Pb2+, Cu2+, and Hg2+ was conducted using five electrochemical techniques: Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV), Normal Pulse Voltammetry (NPV), Differential Pulse Voltammetry (DPV), and Linear Sweep Voltammetry (LSV). SWV emerged as the optimal technique and was termed SWAdSV after the stripping process, displaying peak current responses for Cd2+ (74.7 µA), Pb2+ (42.4 µA), Cu2+ (36.0 µA), and Hg2+ (22.8 µA). Calibration curves were utilized to determine the Limit of Detection (LOD) and Limit of Quantification (LOQ) values for Cd2+, Pb2+, Cu2+, and Hg2+. The repeatability, expressed as %RSD, for the same electrode was found to be 1.70%, 2.04%, 1.14%, and 3.61% for Cd2+, Pb2+, Cu2+, and Hg2+. While the reproducibility, also expressed as %RSD, for different electrodes was determined to be 1.98%, 2.31%, 1.52%, and 1.89% for Cd2+, Pb2+, Cu2+, and Hg2+, respectively. [ABSTRACT FROM AUTHOR]

Excessive intake of nitrite causes serious health problems. Monitoring nitrite levels is necessary for protecting both human health and the environment. Therefore, the fabrication of sensors for rapid detection of nitrite was the aim of this work. We proposed a new method based on an electrochemical sensor prepared from polyrhodamine B (PRhB) coating deposited on polylactic acid modified carbon black (PLA-CB) electrode. The synthesized PRhB/PLA-CB sensor is selective and efficient for nitrite detection, which is based on the interaction between the dimethylamino group of PRhB and nitrite and it has both the advantages of simple preparation and low cost. In optimal experimental conditions, the results of cyclic voltammetry showed that PRhB/PLA-CB, showed significant improvement of the electro-catalytic performance (20%) compared to bare PLA-CB thanks to due to the large surface area and porosity provided by PLA-CB combined with the conductivity and catalytic activity of PRhB. The coating was characterized using the scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The effects of pH and scan rate on nitrite detection were evaluated. The modified electrodes exhibited a remarkable electro-catalytic performance with a wide linear range of 1-10000 µM and low limit of detection (LOD) of 0.342 µM and limit of quantification (LOQ) of 1.036 µM. The proposed sensor was used for the detection of nitrite in tap and commercial water showing good recovery results. [ABSTRACT FROM AUTHOR]

The accurate monitoring of lactate level is very important in the fields of food quality and sport. In the present work, an effective sensor was introduced for lactate monitoring in food and in human bio-fluid. The non-enzymatic electrochemical sensor was fabricated by bulk modification of a simple carbon paste electrode (CPE) with iron-copper ferricyanide (ICF) catalyst and room temperature ionic liquid (IL). The lactate sensing capabilities of the suggested sensor are significantly enhanced due to the combination of the high conductivity of IL and the improved catalytic properties of the ICF modifier. The chronoamperometric response measurements of the ICF-IL-CPE demonstrated a high sensitivity towards lactate across a broad linear range of 20 to 1000 µM, with a correlation coefficient of R2 = 0.999. This sensor also exhibited a detection limit of 4.5 µM, a reproducibility of 3.9% relative standard deviation, and a stability of 95.8% over a period of five weeks. The suggested ICF-IL-CPE depicted minimal background interference against common interfering species. This makes it a highly promising tool for accurately measuring lactate concentrations in various samples including saliva from athletes and cow milk. [ABSTRACT FROM AUTHOR]

In this study, ultrathin CuAl layered double hydroxide (LDH) nanosheets were successfully deposited on sepiolite clay (SPC) support and used as an effective electrocatalyst for fabrication of a new non-enzymatic glucose sensor. According to a series of electrochemical results, the growth of CuAl LDH on SPC decreases the charge-transfer resistance in the surface of modified carbon paste electrode (CPE). At an optimum potential of + 0.40 V, the CuAl LDH/SPC modified CPE depicted a wide linear range over a concentration of 0.1 to 1450 µM with a detection limit of 0.03 µM (S/N = 3). Significantly, the established assay demonstrated a strong resistance to interference from common substances such as fructose, valine, ascorbic acid, urea, L-cysteine, and uric acid. The suggested assay was successfully employed to detect glucose in sport drinks with satisfactory results. The modified electrode with CuAl LDH/SPC presents improved electro-catalytic properties, operating at a lower working potential. It demonstrates rapid response, high stability, and reproducibility in the oxidation of glucose. These features make it a promising candidate for the development of non-enzymatic glucose sensors in the future. [ABSTRACT FROM AUTHOR]

Due to the fusion of culinary cultures, chili products have gained widespread popularity among consumers. Capsaicin, the primary compound responsible for the spiciness of chili products, serves as a pivotal parameter in assessing the quality of chili peppers. A three-dimensional (3D) cell-based electrochemical sensor was developed to detect capsaicin by monitoring the release of hydrogen peroxide (H2O2). The working electrode utilized in this study was a screen-printed carbon electrode (SPCE) that had been modified with AuPtNPs/ZIF-8-RGO. Encapsulation of HepG2 cells within a 4.0 wt% sodium alginate gel enabled their immobilization onto the working electrode, thus serving as the biometric element for signal recording via the amperometric i-t method. H2O2 kit assays showed that H2O2 release increased with increasing capsaicin concentration over a range of concentrations. With a detection limit of 0.848 μM, the developed biosensor effectively detected capsaicin at concentrations that varied from 10 μM to 120 μM. The sensor that was developed displayed exceptional sensitivity, stability, and reliability, offering a novel method for monitoring capsaicin level in food. [ABSTRACT FROM AUTHOR]

Alpha-lipoic acid (α-LA) is a naturally occurring compound that is both water and fat soluble, functioning as a powerful antioxidant in the body. In this study, multi-walled carbon nanotubes (MWCNTs) with SDS were electrodeposited onto a glassy carbon electrode (GCE) electrochemically. This modified electrode was characterized by electrochemical techniques (EIS, CV). The MWCNT/SDS-modified GCE was utilized for the analysis of α-LA. An electrochemical oxidation mechanism for α-LA was proposed using the developed electrochemical sensor. After optimizing the conditions, the MWCNT/SDS-GCE sensor exhibited a linear response in the concentration range of 0.6–9.0 µM, with a detection limit of 0.15 µM. Additionally, this chemical sensor was effectively utilized for the electrochemical analysis of α-LA in the food additive sample. [ABSTRACT FROM AUTHOR]

In the quest for sustainable energy solutions, printable carbon‐based perovskite solar cells (p‐MPSCs) are capturing the industry's attention due to their exceptional stability, simplified assembly, and cost‐effectiveness. At the heart of this innovation lies the carbon electrode, favored for its straightforward printing and assembly processes, making it an ideal candidate for renewable photovoltaic applications that leverage biomass carbon. This study casts the spotlight on rice husks, a plentiful yet underutilized resource, repurposing them into carbon electrodes for p‐MPSCs through a specialized carbonization treatment. A comprehensive examination reveals that the integration of 20% rice husk carbon (RHC) with graphite significantly improves the material's filling and crystalline qualities, diminishes the density of defect states, and strengthens the suppression of nonradiative recombination. These advancements culminate in a notable increase in photovoltaic conversion efficiency, reaching up to 11.49%. This study not only demonstrates the viability of RHC in photovoltaic applications but also supports the efficient use of biomass carbon, contributing to the progression of green energy technologies. [ABSTRACT FROM AUTHOR]

The presented maiden experimental study introduces a novel cell position concept for a modified reversible polymer electrolyte membrane fuel cell with an integrated hydrogen storage (H‐storage) electrode. The primary focus of the current study is to enhance the H‐storage capacity of a carbon‐based self‐standing electrode by testing it in vertical, horizontally upward, and horizontally downward positions to meet U.S. Department of Energy objectives. The results show that the developed cell achieves the highest electrochemical hydrogen adsorption (H‐adsorption) of 1.3 weight percent (wt%) in the horizontal downward position during charging, surpassing the vertical position by 36.1% and outperforming the horizontal upward position by 25.3%. The reversible rates of stored hydrogen are measured as 0.587 wt% in the vertical position, 0.781 wt% in the horizontal upward position, and 0.998 wt% in the horizontal downward position. The cell manages to deliver a peak output of 2.2 V and a maximum current of 0.5 mA during the initial discharging phase. The insights gained from this study on cell positioning are poised to inspire future research efforts aimed at enhancing hydrogen storage capacity and its reversibility. [ABSTRACT FROM AUTHOR]

Copper-based materials play a vital role in the electrochemical transformation of CO2 into C2/C2+ compounds. In this study, cross-sectional octahedral Cu2O microcrystals were prepared in situ on carbon paper electrodes via electrochemical deposition. The morphology and integrity of the exposed crystal surface (111) were meticulously controlled by adjusting the deposition potential, time, and temperature. These cross-sectional octahedral Cu2O microcrystals exhibited high electrocatalytic activity for ethylene (C2H4) production through CO2 reduction. In a 0.1 M KHCO3 electrolyte, the Faradaic efficiency for C2H4 reached 42.0% at a potential of −1.376 V vs. RHE. During continuous electrolysis over 10 h, the FE (C2H4) remained stable around 40%. During electrolysis, the fully exposed (111) crystal faces of Cu2O microcrystals are reduced to Cu0, which enhances C-C coupling and could serve as the main active sites for catalyzing the conversion of CO2 to C2H4. [ABSTRACT FROM AUTHOR]

This experimental study investigates the efficiency of hydrogen production from an aqueous ZnCl 2 solution using an electrochemical method within a chlor-alkali reactor. A laboratory-scale reactor with separate anode and cathode compartments was constructed for this purpose. The compartments are separated by a Nafion 212 membrane, which prevents the mixing of the anolyte and catholyte solutions while allowing the passage of positive ions (Zn+). Each compartment is equipped with five carbon rod electrodes. The anode chamber is fed with an aqueous ZnCl 2 solution, while the cathode chamber is supplied with pure water. The experiments were conducted with a constant electrolyte transfer rate of 0.3g/s into the reactor, at three different cell voltages (5.0, 7.5, and 10.0V) and two different cell temperatures (20 °C and 45 °C). Due to the small reactor dimensions and the dilution effect caused by adding pure water to the cathode compartment which decreases electrolyte density and adversely affects the current a noticeable reduction in hydrogen gas production was observed. Furthermore, the ZnCl 2 electrolyte mass flow rate did not significantly impact the current or the generation of hydrogen and chlorine gases. Consequently, no changes were made to the mass flow rate of pure water or the electrolyte. The presence of active chlorine gas was found to cause the erosion of the carbon rod electrodes in the anode chamber. As a result, the amount of chlorine gas produced in the anode chamber is significantly lower than the hydrogen gas produced in the cathode chamber. At a cell temperature of 20 °C, a mass flow rate of 0.3 g/s, and a cell voltage of 5 V with ZnCl2 aqueous solution, the minimum hydrogen production rate is 0.625 mL/min. In contrast, at a cell temperature of 45 °C, a mass flow rate of 0.3 g/s, and a cell voltage of 10 V, the maximum hydrogen production rate is 4.97 mL/min. • Hydrogen generation of the ZnCl 2. • Performance of the Chlor-alkali reactor for ZnCl 2. • The energetic performance of the system for different conditions. • The effect of heat and power on the hydrogen production. [ABSTRACT FROM AUTHOR]

AbstractHuman Papillomavirus (HPV) is the principal cause of cervical cancer, which is still a prime universal health concern, especially in underdeveloped nations where access to advanced screening techniques is often restricted. Herein, we propose an electrochemical immunosensor for the determination of HPV 16 L1 protein, a key biomarker associated with cervical carcinogenesis. The developed immunosensor, employing glassy carbon electrode (GCE) enhanced with gold nanoparticles, provides a highly sensitive, specific, and cost-effective approach for early screening of cervical cancer. An optimized stepwise fabrication process which includes electrode surface modification and antibody immobilization, was used to enhance sensor performance. Characterization studies confirmed the effective modification of electrodes and the selectivity of immunoreactions. With an impressive limit of detection (LOD) of 0.033 fg mL−1, the immunosensor showed a linear response to L1 protein concentrations ranging from 0.1 fg mL−1 to 1 ng mL−1. Additionally, the immunosensor exhibits excellent specificity, stability, reproducibility, and regeneration capabilities. The performance of the immunosensor was compared with the enzyme-linked immunosorbent assay (ELISA) by analyzing clinical samples (positive: n = 12; healthy: n = 5) showed satisfactory results. The findings indicated that the proposed sensing platform has the potential to be utilized for the early diagnosis of cervical cancer. [ABSTRACT FROM AUTHOR]

High‐performance sensors are in constant demand for health care and environmental protection. In this study, a sensitive paracetamol (PCM) sensor was designed by modifying glassy carbon electrode (GCE) with carbon‐doped boron nitride (BCN/GCE) nanosheets. The BCN nanosheets were synthesized using a molten‐salt method, which ensured the uniformity of size distribution. X‐ray diffraction and transmission electron microscopy results suggested that the carbon‐doping hardly changed the crystal structure and morphology of hexagonal boron nitride (HBN). However, the carbon‐doping can reduce the bandgap, increase the specific surface area and improve the electrical conductivity, which is attributed to the formation of abundant point defects in the BN crystal. These point defects modulate electronic structure and surface activity, and further improve the electrocatalytic properties of BN. The BCN nanosheets exhibited outstanding electrocatalytic activity in the oxidation of paracetamol (PCM). With the help of square wave voltammetry (SWV) method, the BCN/GCE demonstrated linear current response towards PCM covering the concentrations of 0.05–70 μM and 70–200 μM with a detection limit (LOD) of 0.0086 μM. The developed method also showed excellent selectivity and high stability. In addition, the BCN/GCE sensor worked well when it was applied to quantify PCM in actual samples. [ABSTRACT FROM AUTHOR]

ABSTRACT The development of low‐cost, high‐efficiency, stable, and structurally adjustable electrocatalysts for hydrogen evolution reaction (HER) is of great significance for energy conversion. In this study, two new Cu(I) coordination polymers (CPs), formulated as {[Cu(L1)](PF6)·CH2Cl2}n (1) and {[Cu2(L2)1.5(PPh3)](PF6)2}n (2) (L1 = 1,3‐bis[1‐(pyridin‐3‐ylmethyl) ‐1H‐benzimidazol‐2‐yl]propane, L2 = 1,4‐bis[1‐(3‐pyridylmethyl)‐1H‐benzimidazol‐2‐yl]butane), were synthesized by interfacial diffusion method and characterized by single‐crystal x‐ray diffraction and IR and UV–Vis spectra. Structural analysis shows that the CP‐1 is a one‐dimensional chain structure, whereas the CP‐2 is a two‐dimensional layered structure, which is due to the different coordination modes of ligands L1 (bridging chelation) and L2 (bridging). The electrocatalytic activity for HER of Cu(I) CPs was studied by preparing modified glassy carbon electrodes (CP‐1/GCE and CP‐2/GCE). Electrochemical HER studies manifest that in 0.5 M H2SO4, the overpotential (η10298K) and Tafel slope (b 298K) are −769 mV and 173 mV dec−1 for CP‐1/GCE, −933 mV and 301 mV dec−1 for CP‐2/GCE, and −930 mV and 298 mV dec−1 for bare/GCE, respectively. The η10298K and b298K of CP‐1/GCE were significantly positive shifted and decreased compared with the bare/GCE, indicating that CP‐1/GCE has significant electrocatalytic activity and electrocatalytic HER activity order is CP‐1/GCE > CP‐2/GCE ≈ bare/GCE. This work provides an important reference for the application of non‐noble metal CPs in the field of electrocatalysis. [ABSTRACT FROM AUTHOR]

Hybrid electrochemical storage devices combining batteries and supercapacitors are essential for advancing energy storage technologies. Our study presents a simple one-pot synthesis method for nickel-cobalt selenide (NCSe) nanoparticles, optimizing selenium (Se) content to enhance microstructure, porosity, and electrochemical properties. NCSe nanoparticles with 1.8 mmol Se exhibited a remarkable specific capacity of 775 C g⁻1 at 1 A g⁻1 and 665 C g⁻1 with 85 % retention at 15 A g⁻1. An asymmetric supercapacitor using NCSe-1.8 mmol as the positive electrode and activated carbon as the negative electrode achieved 79 % retention after 2000 cycles at 15 A g⁻1. These findings underscore NCSe nanoparticles' potential as efficient electrode materials, advancing energy storage technologies. [ABSTRACT FROM AUTHOR]

The investigation of Ni(OH) 2 electrode materials has been a prominent issue in the field of electrochemical energy. The slow ion diffusion kinetics and inherent low electronic conductivity of Ni(OH) 2 restrict its electrochemical performance and application in practice. In this work, mixed-phase nickel-cobalt layered double hydroxide (NiCoLDH) array structures are successfully grown directly on vertically suspended carbon cloth (CC). In contrast to the traditional hydrothermal method, the vertically suspended carbon cloth affordes adequate reaction sites to ensure optimum array structure growth. This unique structure realizes a large mass loading of the active material. Meanwhile, the introduction of flexible electrode substrate carbon cloth effectively enhances the mechanical properties of the electrode. Due to the powerful electrochemistry kinetics, NiCoLDH/CC-1.5 exhibites a great capacitive and excellent rate performance of 1516.5 F g−1 at 1 A g−1 and 1073.75 F g−1 even at 20 A g−1. The assembled asymmetric supercapacitor demonstrates a favorable cycling stability (capacitance retention of 90.11 % after 10,000 cycles at 5 A g−1). [ABSTRACT FROM AUTHOR]

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AbstractCaffeic acid (CA) based polyurethane (PU) films were synthesized and characterized for the simultaneous determination of melatonin (MT) and serotonin (5-HT). The CA based PUs were synthesized using a polyol mixture of 4,4’-diisocyanodiphenylmethane (MPI), polyethylene glycol-200 (PEG), and CA. The PEG–CA monomer units in the polyol were varied in molar ratios of 99:1, 97:3, 95:5, and 90:10. The synthesized PUs were characterized by FTIR spectroscopy and thermal analysis. These CA based PU films were coated onto screen-printed carbon electrodes (SPCEs) with varying thicknesses and used for the simultaneous determination of MT and 5-HT. Electrochemical responses of MT and 5-HT were evaluated using differential pulse voltammetry. The limit of detection and correlation coefficient for MT were 280 µM and 0.9797, respectively, while for 5-HT, the detection was 150 µM with a correlation coefficient of 0.9690. The precision, expressed as the relative standard deviation was 2.633% for MT and 4.668% for 5-HT. These findings suggest that CA based PU-modified electrodes hold potential in medical and biomedical applications. [ABSTRACT FROM AUTHOR]

Water molecules confined in nanoscale spaces of 2D graphene layers have fascinated researchers worldwide for the past several years, especially in the context of energy storage applications. The water molecules exchanged along with ions during the electrochemical process can aid in wetting and stabilizing the layered materials resulting in an anomalous enhancement in the performance of supercapacitor electrodes. Engineering of 2D carbon electrode materials with various functionalities (oxygen (─O), fluorine (─F), nitrile (─C≡N), carboxylic (─COOH), carbonyl (─C═O), nitrogen (─N)) can alter the ion/water organization in graphene derivatives, and eventually their inherent ion storage ability. Thus, in the current study, a comparative set of functionalized graphene derivatives—fluorine‐doped cyanographene (G–F–CN), cyanographene (G–CN), graphene acid (G–COOH), oxidized graphene acid (G‐COOH (O)) and nitrogen superdoped graphene (G–N) is systematically evaluated toward charge storage in various aqueous‐based electrolyte systems. Differences in functionalization on graphene derivatives influence the electrochemical properties, and the real‐time mass exchange during the electrochemical process is monitored by electrochemical quartz crystal microbalance (EQCM). Electrogravimetric assessment revealed that oxidized 2D acid derivatives (G–COOH (O)) are shown to exhibit high ion storage performance along with maximum water transfer during the electrochemical process. The complex understanding of the processes gained during supercapacitor electrode charging in aqueous electrolytes paves the way toward the rational utilization of graphene derivatives in forefront energy storage applications. [ABSTRACT FROM AUTHOR]

The gradual capacity decrease of vanadium redox flow battery (VRFB) over long‐term charge‐discharge cycling is determined by electrolyte degradation. While it was initially believed that this degradation was solely caused by crossover, recent research suggests that oxidative imbalance induced by hydrogen evolution reaction (HER) also plays a significant role. In this work by using vanadium pentoxides with different impurities content, we prepared three grades of vanadium electrolyte. By measuring electrochemical properties on carbon felt electrode in three‐electrode cell and VRFB membrane‐electrode assembly we evaluate the influence of impurity content on battery polarization and rate of side reactions which is indicated by the increase of average oxidation state (AOS) during charge‐discharge tests and varies from 0.061 to 0.027 day−1 for electrolytes made from 99.1 and 99.9 wt % V2O5. We found that increase of AOS correlates with the increase of open‐circuit voltage of VRFB in the discharged state ranging from 9.6 to 14.9 mV day−1 for highest and lowest electrolyte purity levels, respectively. While AOS increase is significant, it does not solely determine capacity fade. It is demonstrated that the presence of vanadium crossover decreases capacity fade, i. e. levels the contribution of side reactions on capacity drop. [ABSTRACT FROM AUTHOR]

Herein we introduce a novel water-based graphite ink modified with multiwalled carbon nanotubes, designed for the development of the first wearable self-powered biosensor enabling alcohol abuse detection through sweat analysis. The stencil-printed graphite (SPG) electrodes, printed onto a flexible substrate, were modified by casting multiwalled carbon nanotubes (MWCNTs), electrodepositing polymethylene blue (pMB) at the anode to serve as a catalyst for nicotinamide adenine dinucleotide (NADH) oxidation, and hemin at the cathode as a selective catalyst for H2O2 reduction. Notably, alcohol dehydrogenase (ADH) was additionally physisorbed onto the anodic electrode, and alcohol oxidase (AOx) onto the cathodic electrode. The self-powered biosensor was assembled using the ADH/pMB-MWCNTs/SPG||AOx/Hemin-MWCNTs/SPG configuration, enabling the detection of ethanol as an analytical target, both at the anodic and cathodic electrodes. Its performance was assessed by measuring polarization curves with gradually increasing ethanol concentrations ranging from 0 to 50 mM. The biosensor demonstrated a linear detection range from 0.01 to 0.3 mM, with a detection limit (LOD) of 3 ± 1 µM and a sensitivity of 64 ± 2 μW mM−1, with a correlation coefficient of 0.98 (RSD 8.1%, n = 10 electrode pairs). It exhibited robust operational stability (over 2800 s with continuous ethanol turnover) and excellent storage stability (approximately 93% of initial signal retained after 90 days). Finally, the biosensor array was integrated into a wristband and successfully evaluated for continuous alcohol abuse monitoring. This proposed system displays promising attributes for use as a flexible and wearable biosensor employing biocompatible water-based inks, offering potential applications in forensic contexts. A novel water-based graphite ink modified with multiwalled carbon nanotubes designed for the development of a wearable self-powered biosensor enabling alcohol abuse detection through sweat analysis. [ABSTRACT FROM AUTHOR]

The accurate and rapid detection of persulfate concentration is important for environmental decontamination and human health protection. In this work, a novel self-powered electrochemical sensor for the sensitive monitoring of persulfate was developed, which utilized cobalt tetroxide (Co3O4@CC) or tin-doped cobalt tetroxide (SnxCo3−xO4@CC) cathode as the sensing element and anode with electrogenic microorganisms as the power supplier. The Co3O4@CC and SnxCo3−xO4@CC electrodes were fabricated by in situ growing nanostructured Co3O4 or SnxCo3−xO4 catalysts on carbon cloth. Electrochemical tests revealed that these electrodes exhibited excellent catalytic reduction performance toward persulfate because of the synergistic catalysis by Co3O4 and electrode electrons, well-exposed Co2+/Co3+ catalytic sites, and high electron transfer efficiency. Tin doping could enhance the catalytic persulfate reduction by improving the conductivity and electron transfer of the Co3O4 catalyst. The electrode prepared at a hydrothermal temperature of 90 °C and a tin dosage of 0.286 g·cm−2 achieved the highest persulfate reduction activity under pH 7. The sensing properties of the self-powered sensors toward persulfate were explored in detail. Results showed that under the optimal external load of 300 Ω, the proposed sensor could display a broad detection range of 0 to 1500 μmol L−1 K2S2O8 with sensitivities of 1.13 and 0.12 μA μmol−1 L, a detection limit of 1.11 μmol L−1 (S/N = 3), and a fast response time within 30 s. The sensors also presented satisfactory reproducibility and selectivity during the detection of persulfate. The proposed sensor will provide a new approach for sensitive, on-site, and real-time monitoring of persulfate for a wide range of applications. [ABSTRACT FROM AUTHOR]

In this study, we present a facile approach for the green synthesis of polyaniline (PANI) through electrochemical polymerization on a graphitic paste electrode, thus enhancing its use in electrochemical sensing applications. The morphology of the synthesized PANI was observed using scanning electron microscopy (SEM), the crystallinity of the material was studied using XRD, and further functional groups were characterized by FT‐IR and UV spectroscopy. PANI, coated on the surface of a graphitic paste ‐modified electrode (P‐GPME) by controlled electrolysis, demonstrated notable electrocatalytic activity toward L‐cysteine (L‐cyst). The redox behavior of L‐cyst at the P‐GPME surface was investigated using cyclic voltammetry. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 2.4 × 10−6 and 1.21 × 10−5 mol L−1, respectively. These results highlight the potential of P‐GPME for selective and sensitive detection of L‐cyst. Furthermore, the designed electrode was effectively employed for the determination of L‐cyst in urine samples. [ABSTRACT FROM AUTHOR]

This study introduces a series of Rh–Pd bimetallic aerogels Rh 75 Pd 25 , Rh 50 Pd 50 , and Rh 25 Pd 75 as efficient electrocatalysts for ethanol electrooxidation, crucial for direct ethanol fuel cell technology. The bimetallic Rh–Pd and monometallic Rh and Pd aerogels were synthesized from RhCl 3 and PdCl 2 as starting materials and sodium borohydride as the reducing agent. A combination of X-ray photoelectron spectroscopy, elemental mapping, and electron microscopy studies of the bimetallic aerogels enable compositional analysis of the materials and provide insight into the porous 3D nanoarchitecture. Importantly, the material performs efficiently as an electrocatalyst on glassy carbon electrodes for the oxidation of ethanol under basic conditions (1.0 M KOH) at onset potentials ranging from −0.59 to −0.64 V (vs. Hg/HgO). Importantly, these materials exhibit high peak current densities of 216 mA/cm2 for the Rh-rich Rh 75 Pd 25 to 536 mA/cm2 for Rh 25 Pd 75 , which are significantly higher than reported peak current densities for other Pd-containing electrocatalysts. The 1H and 13C NMR techniques were used to evaluate products for ethanol electrooxidation, with the results indicating selectivity for acetic acid. This demonstrates an enhanced catalytic activity, selectivity to acetic acid vs. CO 2 , representing a significant step in advancing DEFCs and their broader application in sustainable energy technologies. [Display omitted] • Synthesis different Rh–Pd bimetallic aerogels Rh 75 Pd 25 , Rh 50 Pd 50 , and Rh 25 Pd 75. • Highly efficient electrocatalysts for ethanol electrooxidation. • Significant enhancements in catalytic activity to 536 mA/Cm2. • Bimetallic Rh–Pd aerogels selectively convert ethanol to acetic acid. [ABSTRACT FROM AUTHOR]