Properties Of Electrodes Research Articles

Functionalization of Carbon Electrode Surface Using Polyaniline and Gold Nanoparticles for Protein Immobilization

This study presents a screen-printed carbon electrode surface functionalization to immobilize proteins. The process involves the deposition of gold nanoparticles on the carbon electrode and subsequent surface modification to immobilize bovine serum albumin–fluorescein isothiocyanate conjugate (BSA-FITC). A combination of conducting polymer and gold nanoparticles was employed to enhance the electrode contact area and current transmission. The electrode surface morphology and properties were evaluated by scanning electron microscopy (SEM) and Raman spectroscopy, showing the porous polyaniline (PANI) film has been formed on the carbon electrode surface with the network of dendritic nanofibers. Gold nanoparticles were evenly distributed on the PANI film to form a nanocomposite material layer on the carbon electrode. The observed size of these gold nanoparticles was significantly smaller than those on the electrode without a PANI film. Additionally, the current transmission of this composite material layer has been verified by cyclic voltammetry (CV). The results show that the amplitude of the redox peak was doubled compared to the bare carbon electrode and gold nanoparticle-only deposited electrode. Moreover, the success of the process was verified by fluorescence and cyclic voltammetry. The fluorescent green color observed under the microscope indicated that BSA-FITC was on the electrode surface. The change of CV signal after each step verified the formation of a new layer on the electrode surface. These results are anticipated to play an important role in developing high-sensitivity immunosensors in the future.

Development of the BAT-26 mutation-based electrochemical genosensor for identifying microsatellite instability in relationship to cancer

Screening for microsatellite instability is one of the biggest challenges in the cancer diagnosis due to its association with different types of cancer development. In this sense, the development of fast and highly sensitive analytical devices for early the cancer detection is a high priority. In the present work, a highly sensitive electrochemistry genosensor is developed and described for BAT-26 mutation detection using: differential pulse voltammetry (DPV), and cyclic voltametric (CV) supported by scanning tunnel microscopy (STM). The redox reaction of Fe(CN)63−/4– was monitored to probe the presence DNA target. The results demonstrate that modifying the screen-printed gold electrode surface (SPGE) 250AT with a combination of 11-mercaptoundecanoic acid (MUA) and a single-stranded DNA oligonucleotide successfully altered the electrode's properties, particularly its affinity for detecting the BAT-26 mutation under physiological conditions. The genosensor exhibited a wide linear range (100 aM to 1 μM) and achieved a low detection limit of 71.74 aM under optimal parameters. These characteristics, coupled with its high sensitivity and rapid analysis time, make it a promising candidate for development into a portable microsatellite instability diagnostic kit.

Binder-Free CNT-Modified Excellent Electrodes for All-Vanadium Redox Flow Batteries.

Electrodes are one of the key components that influence the performance of all-vanadium redox flow batteries (VRFBs). A porous graphite felt with modified fiber surfaces that can provide a high specific activation surface is preferred as the electrode of a VRFB. In this study, a simple binder-free approach is developed for preparing stable carbon nanotube modified graphite felt electrodes (CNT-GFs). Heat-treated graphite felt electrodes (H-GFs) are dip-coated using CNT homogeneous solution. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results conclude that CNT-GFs have less resistance, better reaction currents, and reversibility as compared to H-GF. Cell performances showed that CNT-GFs significantly improve the performance of a VRFB, especially for the CNT-GF served in the positive side of the VRFB. CNT presence increases the electrochemical properties of the graphite electrode; as a result, reaction kinetics for both VO2+/VO2+ and V3+/V2+ are improved. Positive CNT-GF (P-CNT-GF) configured VRFB exhibits voltage efficiency, coulombic efficiency, and energy efficiency of 85%, 97%, and 82%, respectively, at the operating current density of 100 mA cm-2. At high current density of 200 mA cm-2, the VRFB with P-CNT-GF shows 73%, 98%, and 72% of the voltage, coulombic, and energy efficiencies, respectively. The energy efficiency of the CNT-GF is 6% higher when compared with that of B-H-GF. The VRFB with CNT-GF can provide stable performance for 300 cycles at 200 mA cm-2.

Synthesis, characterization, and application of ZnO@SiO2-APTES core-shell composite for selective electrochemical detection of Pb2+ ions

This study focuses on improving the electrochemical performances for the detection of heavy metals such as Pb2+ by using a silica-based nanomaterial. In order to do this, ZnO nanoparticles (core) were used as a seed for the chemical deposition of a SiO2 shell. The nanomaterial was synthesized according to a core-shell configuration and the obtained particles were subsequently functionalized with (3-aminopropyl) triethoxysilane APTES to enhance their electrochemical sensing capabilities. The unique physical and chemical properties of these particles, such as their uniform porosity and their ability to detect Pb2+, were exploited. The resulting composite was characterized by scanning electron microscopy, X-ray diffraction, and infrared spectroscopy to analyze its morphology and chemical composition. An electrochemical characterization was also performed to evaluate the change in electrode properties with a ZnO@SiO2-APTES-modified glassy carbon electrode. The differential pulse voltammetry technique was used to determine the Pb2+ ion concentration. After optimization, the electrochemical sensor based on ZnO@SiO2-APTES showed significant sensitivity and exceptional performance in the detection of Pb2+ with a limit of detection of 0.1 nM. Moreover, the proposed electrochemical sensor was successfully applied in the determination of trace metal ions in real environmental samples.

Growth of CQD/PPy on cotton cloth as a binder-free high-performance flexible electrode for symmetric supercapacitor

Benefited from the continuous development of nanomaterials, wearable microelectronics with flexible and miniaturized features are booming, and smart textiles are attracting more attentions because of their superior flexibility and perfect safety. The combination of conductive polymers and flexible substrates has created a new field for flexible supercapacitors. Herein, cotton cloth (CC), which is commonly used in daily life, was selected as the flexible substrate and a layer of CQDs was uniformly grown on the CC fibers, and then pyrrole was directly grown on CC by in-situ polymerization under Fe3+ initiation to realize the tight bonding between the conductive polymer and the flexible substrate. The electrochemical properties of the composite electrode could be controlled by changing the amount of CQD. The obtained CC@CQD@PPy electrode has a high specific capacitance (C) of 537.9 F/g at 0.5 A/g. The assembled symmetric CC@CQD@PPy supercapacitor exhibits an excellent energy density (E) of 18.7 Wh/kg at a power density (P) of 125.0 W/kg, and a supreme cycling stability with a capacitance retention of 77.9 % after 10,000 cycles. In addition, the CC@CQD@PPy supercapacitor has excellent flexibility, with almost unchanged electrochemical performance under different bending angles, and the assembled all-solid-state supercapacitor has good electrochemical properties.

High-entropy layer assisting quasi-zero-strain cathodes for P2-Na2/3Ni1/3Mn2/3O2

Layered transition metal oxides have attracted much attention for high-energy density sodium ion batteries. However, most P2-type layered oxides undergo a large volume change when they are charged at a deep desodiated state, accompanied by inevitable anisotropic stress, leading to poor structural stability and terrible ion transfer. In this work, a high entropy (HE) material with a robust structure and fast ion transportation was decorated on P2-Na2/3Ni1/3Mn2/3O2 (NM) layered oxides. The unique characteristics of HE shells with similar lattice constants could effectively depress particle crack and exfoliation through buffering severe lattice strains, thus leading to enhanced cycling stability and kinetic properties of the HE-NM electrode. In situ x-ray diffraction analysis confirms that the volume expansion of NM could be prominently restrained both under thermal treatments and electrochemical after HE decoration. The modified cathode exhibits a volume change as low as 0.5%. The findings highlight the significance and superiority of the HE coating layer and provide insight for the rational design of high-performance sodium-ion batteries.

Layered Siloxene Microparticles: Unveiling Long-Term Stability and High Volumetric Capacity for Advanced Lithium-Ion Batteries

Two-dimensional (2D) Si π materials, a silicon counterpart of graphene, are particularly interesting because they exhibit intrinsic electrochemical and mechanical behavior combined with structural anisotropy. This work aims to improve the Li-storage performance of 2D siloxene (2DSi) microparticles by co-imidization with polymer binder. The proposed method combines 2DSi with poly(amic acid) to form a covalently bound poly(imide) (PI) layer upon thermal dehydration. Electrochemical evaluations reveal that the resulting 2DSi-PI electrode exhibits a unique electrochemical behavior toward Li+ based on intercalation, with additional reversible (de-)lithiation attributed to carbonyl oxygens of PI. Without suffering volume expansion, the 2DSi-PI electrodes display a highly stable capacity generation of 585 mAh g−1 at 250 mA g−1 with a capacity loss of 0.13 % per cycle at the 200th cycle. In addition, the full-cell of the 2DSi-PI electrode combined with the LiNi0.8Co0.1Mn0.1O2 cathode achieves an energy density of 426 Wh kg−1 at a power density of 1,155 W kg−1. Ex-situ and theoretical analyses of the (de-)lithiated 2DSi-PI electrodes demonstrate that the surface-bound PI suppresses solvent reduction, increases the amount of LiF in the SEI layer, and improves the binding affinity of 2DSi to LiF. As a result, the cycle stability of 2DSi-PI electrodes is significantly improved in comparison to 2DSi-polyvinylidene fluoride electrodes. Co-imidization with PI emerges as a promising strategy for advancing the electrochemical properties of 2DSi electrodes, offering insights for the design of high-performance lithium-ion battery anodes.

Electrochemically polymerized dopamine activated carbon paste sensor for selective and sensitive detection of rutin in the presence of riboflavin

In this work, a sensor was developed for the quantification of RT in food and medicine samples using electro-polymerization of dopamine (DA) on the surface of a carbon paste electrode in 0.2 M phosphate buffered saline (PBS) of 7.0 pH by cyclic voltammetry (CV). The surface properties of bare carbon paste electrode (BCPE) and poly (DA) modified carbon paste electrode (PDAMCPE) were studied using scanning electron microscopy (SEM), electrochemical impedance study (EIS), and CV techniques. Two electron two proton transfer process was seen during the electrochemical reaction of RT with adsorption-controlled process. Under optimum conditions, the peak current increased linearly with an increase in RT concentration for CV in the range of 0.4 to 2.0 μM and differential pulse voltammetry (DPV) in the range of 0.4 to 2.5 μM and the limit of detection (LOD) was found to be 0.0045 μΜ and for CV and 0.079 μM for DPV techniques respectively. Even in the presence of some interferents like organic compounds and metal ions, the developed electrode exhibits good anti-interference ability for RT, and good selectivity was obtained for RT in the presence of riboflavin (RF). The developed sensor presents good stability, repeatability, and reproducibility. The CV measurement was performed for the analysis of RT in real samples such as green tea and medicine samples which showed a good recovery and this work has been not reported previously.

Solution blow spun Co3O4 nanofibers as electrocatalyst for oxygen evolution processes

In this study, Co3O4 nanofibers were produced using the solution blow spinning (SBS) method. The investigation focused on studying their structure, morphology, and electrocatalytic properties in relation to the oxygen evolution reaction (OER) in alkaline solution (KOH). Calcination at 600 °C resulted in Co3O4 fibers without the presence of secondary phases (NF600), while calcined fibers at 400 °C showed a Co3O4–CoO composite phase (NF400), confirmed by XRD. The size of the crystallites, determined through Rietveld refinement analysis of XRD patterns, ranged from 42.6 nm to 56.2 nm for the calcined fibers at 400 °C and 600 °C, respectively, confirming the nanometric scale of the cobalt oxide fibers. Morphological analyses confirmed the production of rough nanofibers with monomodal distribution, with mean diameter of 385 nm for NF600 and 485 nm for NF400. The EDS confirms the presence of the chemical elements of cobalt and oxygen, estimating their abundance in the sample. The XPS analysis showed that the concentration of oxygen vacancies and the presence of species with higher oxidation states (Co3+) were beneficial to improve OER. Nanofibers calcined at 600 °C showed an overpotential of 330 mV at 10 mA cm−2, more efficient Tafel kinetics and low resistance to charge transfer (0.37 Ω) when compared to nanofibers calcined at 400 °C (338 mV). This result demonstrates the competitive catalytic activity of cobalt oxide nanofibers produced by SBS compared to other systems mentioned in the literature. Therefore, this work offers a new perspective on the development of electrocatalysts based on the structure and properties of cobalt oxide electrodes by the SBS method.

Effects of Solvents on the Material Properties of Screen‐Printed Electrodes and a Polydimethylsiloxane Dielectric for Dielectric Elastomer Transducers

Dielectric elastomer transducers (DETs), namely, highly stretchable dielectric membranes sandwiched between two compliant electrodes, allow to develop sensors, actuators, and generator systems. DET performance is strongly influenced by the material properties of dielectric and electrodes, as well as the type of manufacturing process. For instance, when manufacturing the electrodes via screen‐printing, significant amounts of solvents are needed to adjust the printing materials’ viscosity, but they potentially alter DET properties. The investigation of this effect, however, is largely unexplored. Addressing this issue, this article investigates the influence of various solvents on a DET consisting of a polydimethylsiloxane (PDMS) membrane with PDMS/carbon black electrodes. Physical and chemical interactions between dielectric and solvents are characterized by infrared‐spectroscopy (IR), optical investigations, and light microscopy. Different solvents used for screen‐printing are analyzed in terms of their effects on the electrode electrical resistance, screen‐print image, and breakdown strength. Even though the solvent strongly affects the electrodes’ electrical resistance (ranging from ≈22 kΩ to >MΩ), it does not modify the breakdown strength of the pure dielectric (113 V μm−1). In the IR, no chemical aging is found. The obtained results provide systematic guidelines for the choice of solvents in DET electrode manufacturing.

Enhancing the Electrochemical Performance of ZnO-Co3O4 and Zn-Co-O Supercapacitor Electrodes Due to the In Situ Electrochemical Etching Process and the Formation of Co3O4 Nanoparticles

Zinc oxide (ZnO) and materials based on it are often used to create battery-type supercapacitor electrodes and are considered as promising materials for hybrid asymmetric supercapacitors. However, when creating such electrodes, it is necessary to take into account the instability and degradation of zinc oxide in aggressive environments with a non-neutral pH. To the best of our knowledge, studies of the changes in the properties of ZnO-containing electrodes in alkaline electrolytes have not been carried out. In this work, changes in the structure and properties of these electrodes under alkaline treatment were investigated using the example of ZnO-containing composites, which are often used for the manufacturing of supercapacitor electrodes. Supercapacitor electrodes made of two materials containing ZnO were studied: (i) a heterogeneous ZnO-Co3O4 system, and (ii) a hexagonal h-Zn-Co-O solid solution. A comparison was made between the structure and properties of these materials before and after in situ electrochemical oxidation in the process of measuring cyclic voltammetry and galvanostatic charge/discharge. It has been shown that the structure of both nanoparticles of the heterogeneous ZnO-Co3O4 system and the h-Zn-Co-O solid solution changes due to the dissolution of ZnO in the alkaline electrolyte 3.5 M KOH, with the short-term alkaline treatment producing cobalt and zinc hydroxides, and long-term exposure leading to electrochemical cyclic oxidation–reduction, forming cobalt oxide Co3O4. Since the resulting cobalt oxide nanoparticles are immobilized in the electrode structure, a considerable specific capacity of 446 F g−1 or 74.4 mA h g−1 is achieved at a mass loading of 0.0105 g. The fabricated hybrid capacitor showed a good electrochemical performance, with a series resistance of 0.2 Ohm and a capacitance retention of 87% after 10,000 cycles.

Comparative Evaluation of Graphite Anode Structuring for Lithium‐Ion Batteries Using Laser Ablation and Mechanical Embossing

Lithium‐ion batteries inherently suffer from a target conflict between a high energy density and a high power density. The creation of microscopic holes in the electrodes alleviates the trade‐off by facilitating lithium‐ion diffusion. This study presents a novel concept for electrode structuring called structure calendering, combining mechanical embossing (MEC) and calendering. It is compared to the widely investigated laser ablation (LAS) process by structuring graphite anodes and examining their geometrical, mechanical, and electrochemical properties. It is shown that structure calendering results in wider and deeper holes of higher reproducibility than laser structuring. As a consequence of the different hole‐creation mechanisms, laser structuring induces a surface elevation around the holes while clogged pores are observed in the lateral walls of mechanically structured holes. In pull‐off tests, no pronounced impact of electrode structuring on the mechanical electrode properties is discerned. Structuring of electrodes using both methods yields significantly reduced electrode tortuosities and enhanced discharge rate performances. From a production engineering perspective, structure calendering has advantages over laser structuring in terms of material loss, processing rate, and investment costs, while the latter offers higher flexibility, precision, and presumably lower maintenance efforts. In conclusion, structure calendering represents an attractive process alternative to laser structuring.

A New Planar Potentiometric Sensor for In Situ Measurements.

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

Iodonium-based pro-adhesive layers for robust adhesion of PEDOT:PSS to surfaces

ABSTRACT Electrochemical grafting of organic molecules to metal surfaces has been well-known as an efficient tool enabling tailored modification of surface at the nanoscale. Among many compounds with the ability to undergo the process of electrografting, iodonium salts belong to less frequently used, especially when compared with the most popular diazonium salts. Meanwhile, due to their increased stability, iodonium salts may be used in situations where the use of diazonium salts is constrained. The aim of this study was to examine the effect of the electrochemical reduction of iodonium salts on the physicochemical properties of Pt electrodes, and the possibility to form pro-adhesive layers facilitating further functionalization purposes. Consequently, we have selected four commercially available iodonium salts (diphenyliodonium chloride, bis(4-tertbutylphenyl)iodonium hexafluorophosphate, (4-nitrophenyl)(2,4,6-trimethylphenyl)iodonium triflate, bis(4-methylphenyl)iodonium hexafluorophosphate), and attached them to the surface of Pt electrodes by means of an electrochemical reduction process. As-formed layers were then extensively characterized in terms of wettability, roughness and charge transfer properties, and used as pro-adhesive coatings prior to the deposition of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS. Due to the increase in hydrophilicity and roughness, modified electrodes increased the stability of PEDOT:PSS coating while maintaining its high capacitance.

Effects of lanthanide doping on the electrode properties and exsolution behavior of A-site deficient Sr1.9Fe1.3Ni0.2Mo0.5O6-δ double perovskites

Double perovskite oxides of the Sr2Fe1.5Mo0.5O6-δ class are promising electrodes for Solid Oxide Fuel Cells (SOFCs) and Electrolyzers (SOECs) due to their outstanding electrochemical properties and durability. Additionally, their physicochemical properties can be tuned by B-site cation doping, namely, by partially substituting Fe cations with other transition metals such as Ni, Co, Mn, or Cu. This also allows the grain-surface functionalization with metallic alloyed nanocatalysts upon reduction driven by the exsolution phenomena, leading to higher electrocatalytic activity and resistance against sintering and coking. Traditionally, A-site deficiency has been employed to improve the amount of exsolved nanoparticles and, thereby, increase the number of Triple Phase Boundaries in the electrode. However, in Ni-doped non-stoichiometric double perovskite materials (e.g., Sr1.9Fe1.3Ni0.2Mo0.5O6-δ), A-site deficiency results in undesired NiO phase segregations. This, in turn, lowers the number of exsolvable cations, decreasing the number of metallic nanocatalysts compared to the stoichiometric compound. In this work, the impact of A-site doping with lanthanides (viz. Gd, La, Nd, and Pr) on the exsolution ability and electrochemical properties of non-stoichiometric Sr1.9Fe1.3Ni0.2Mo0.5O6-δ was evaluated. The results indicate that lanthanide doping enhances the conductivity of the double perovskites both in oxidizing and reducing atmospheres. In addition, lanthanide dopants that slightly destabilize the cubic structure also improve the exsolution dispersion, which decreases with increasing the double perovskite cell volume. These results illustrate how to design more efficient and durable electrocatalysts by modifying the double perovskite structure with A-site dopants.

Application of Multistage Drying Profiles for Accelerated Production of Li‐Ion Battery Anodes Using Infrared Radiation: Validation with Electrochemical Performance and Structural Properties

The drying of solvent‐processed electrodes is a critical process step in the manufacturing of lithium‐ion batteries. The technology used to introduce the energy required for drying into the material, combined with the specified process parameters, significantly influences the resulting electrode properties. A major challenge is to counteract binder migration effects that may occur during drying of the porous electrode structure, causing a decrease in adhesion and electrochemical performance, especially for high drying rates. From this motivation, investigations on the influence of process design during near‐infrared drying of aqueous‐processed graphite anodes are carried out. A multistage drying design with varying parameters in specific drying sections with energy input by radiation is applied. The results show that the specific application of a three‐stage drying profile in combination with energy input by radiation enables a significant decrease in drying time by at least 60% while the electrode properties can be preserved. These findings indicate a beneficial development of binder distribution as a consequence of multistage NIR drying, evidenced by adhesion and electrochemical performance. Finally, the application of the multistage drying profile is theoretically transferred to an industrial‐scale roll‐to‐roll dryer, whereby the necessary dryer length can be reduced by 53%.

Dynamic Effect of Overscreening on Electrochemical and Thermal Properties of EDLC Electrodes during Charging/Discharging Cycles

Overscreening was commonly observed during charging/discharging cycles of electric double layer capacitors(EDLCs). This study presented a two-dimensional continuum electrochemical thermal model with a distribution function for concentration considering overscreening to investigate how overscreening affected the dynamic formation of electric double layer (EDL) near electrodes in macroscale. The results indicated that ion distribution was co-affected by EDL formation and overscreening near the electrode. Correspondingly, layered space charge density distribution resulted in a thicker diffuse layer, whose thickness was determined by the sum of co-ion and counter-ion diameters. Additionally, the diffuse layer capacitance was proportional to the reciprocal of counter-ion diameter, while the total capacitance was proportional to a linear combination of counter-ion and the larger ion diameters. Moreover, the shift from endothermic to exothermic for the total heat generation rate was dominated by heat of mixing, and was caused by the local ion mixing due to overscreening, resulting in local entropy increase. The results of this study can be used to further investigate the effect of overscreening on ion transient transport dynamic and heat generation rates.

Fractal Properties of Composite-Modified Carbon Paste Electrodes—A Comparison between SEM and CV Fractal Analysis

The fractal properties of carbon paste electrodes (CPEs) and carbon paste electrodes modified with ionic liquid (IL), AuTiO2/graphene oxide, and IL/AuTiO2/graphene oxide were investigated using scanning electron microscopy (SEM), and cyclic voltammetry (CV). The impact of fractal dimensions and self-similarity ranges on electrochemical responses was underlined. It was proved that a higher fractal dimension and a broad self-similarity domain lead to a higher electrochemical response. Results indicated that IL/AuTiO2/graphene oxide composite-modified CPEs are a great candidate to be used as electrochemical sensors, with a high fractal dimension and large self-similarity domain.

Design and fabrication of electrochemical sensor based on NiO/Ni@C-Fe3O4/CeO2 for the determination of niclosamide

In this study, we aimed to enhance and accelerate the electrochemical properties of a glassy carbon-based voltammetric sensor electrode. This was achieved through the modification of the electrode using a nanocomposite derived from a metal–organic framework, which was embedded onto a substrate consisting of metal oxide nanoparticles. The final product was an electrocatalyst denoted as NiO/Ni@C-Fe3O4/CeO2, tailored for the detection of the drug niclosamide. Several techniques, including FT-IR, XRD, XPS, FE-SEM, TEM, and EDS, were employed to characterize the structure and morphology of this newly formed electroactive catalyst. Subsequently, the efficiency of this electrocatalyst was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Differential pulse voltammetry was also utilized to achieve heightened sensitivity and selectivity. A comprehensive exploration of key factors such as the catalyst quantity, optimal instrumental parameters, scan rate influence, and pH effect was undertaken, revealing a well-regulated reaction process. Furthermore, the sensor's analytical performance parameters were determined. This included establishing the linear detection range for the target compound within a specified concentration interval of 2.92 nM to 4.97 μM. The detection limit of 0.91 nM, repeatability of 3.1%, and reproducibility of 4.8% of the sensor were calculated, leading to the observation of favorable stability characteristics. Conclusively, the developed electrochemical sensor was successfully employed for the quantification of niclosamide in urine samples and niclosamide tablets. This application highlighted not only the sensor’s high selectivity but also the satisfactory and accurate outcomes obtained from these measurements.

Enhanced electrochemical properties of cobalt oxide nanoparticle electrode modified with low concentration of cationic surfactant

Metal oxides are proficient electrode materials for supercapacitors because of their physiochemical properties, especially their wide range of oxidation states that facilitate charge transfer in redox reactions and compatibility with electrolytes. Their performances can be further improved by adding surfactants, which also help with controlled synthesis, inhibit aggregation, and alter surface characteristics. The functional groups present in the surfactant molecule can undergo chemical bonding with the surface of the metal oxide, thereby modifying their surface chemistry and electronic characteristics. Recent research has focused on increasing the specific capacitance of cobalt oxide owing to its large surface area and size. The surfactants help to control the surface modification as a size-reducing agent and improve the electrochemical properties. Herein, A facile co-precipitation method is employed in synthesising cobalt oxide without cationic surfactant cetyltrimethylammonium bromide (CTAB) and with different concentrations of CTAB, followed by calcination. Herein, we compare the electrochemical properties with varying concentrations of surfactant-assisted Co3O4. The modified Co3O4 electrode with a low surfactant concentration (CO 1) exhibits a highly specific capacitance of 531F/g at 5 mV/s with a potential window of 0.7 V. The CO 1 electrode is suitable for supercapacitor devices with a specific capacitance of 296F/g at 0.8 A/g. Moreover, the asymmetric supercapacitor composed of CO1//AC demonstrated a remarkable energy density of 46.2 Wh/Kg and a robust power density of 800 W/kg. These results indicate that the hierarchical porous structure accelerates electron and ion movement, lowers charge transfer resistance, and improves hybrid electrode capacitive properties.