The development of ZnCo alloys appeared as alternative for obtaining layers more resistant than the conventional zinc with a minimum increment of cost. The aim of this work is to study the ...electrodeposition mechanism of the ZnCo alloy on SAE 1020 carbon steel by cyclic voltammetry using two baths with different Zn2+/Co2+ concentration ratios and also to evaluate the corrosion resistance in 0.1 mol L−1 NaCl of electrodeposits obtained potentiostatically using electrochemical techniques as electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization curves. The voltammograms showed two anodic peaks attributed to dissolution of zinc rich ƞ-phases and cobalt, and a cathodic peak related to ZnCo alloy deposition. The nucleation mechanisms were examined by fitting the experimental data (chronoamperometry) into the Scharifker and Hills nucleation models. Scanning electron microscopy (SEM) showed that the electrodeposits obtained for the Zn2+/Co2+ 9:1 ratio presented a structure in the form of hexagonal platelets in comparison to the electrodeposits with Zn2+/Co2+ 12:1 ratio, which presented cauliflower-shaped structures. On the other hand, the electrochemical techniques proved that the electrodeposits obtained for the Zn2+/Co2+ 9:1 ratio at potential of −1450 mV presented the best anticorrosive properties. Structural and chemical characterization of coatings was accomplished by XRD and XRF.
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•Hydrothermally grown NiCo2O4 nanoparticles are drop cast on fluorine doped tin oxide electrode (NCO@FTO).•NCO@FTO electro-oxidizes hydroxylamine (HYA) at 0.6 V vs. Ag/AgCl giving a 1.7-fold higher ...peak current than FTO.•As a chronoamperometric sensor NCO@FTO, detects HYA in a wide range from 10 to 4000 µM.•Sensor has a low detection limit of 0.47 µM, a high sensitivity of 408 μA mM−1 cm−2, and a response time of less than 3 s.•FTO is introduced as a suitable base electrode for the electro-oxidation of HYA.
The design and development of inexpensive, and extremely sensitive sensors for Hydroxylamine (HYA) are imperative due to its toxicity to animals, plants, and aquatic life. This work proposes a high-performance enzyme-free electrochemical sensor for HYA based on its oxidation on Nickel cobaltite (NCO) spinel-modified fluorine doped tin oxide (FTO) electrode. Hydrothermally grown irregularly shaped NCO nanoparticles (NPs) of size around 10 nm are characterized by XRD, XPS, UV–visible, BET, and TEM to evaluate the structural and morphological characteristics. NCO-modified FTO (NCO@FTO) electro-oxidizes HYA at a potential of 0.66 V vs. Ag/AgCl, delivering 1.7 times the current response than bare FTO. The rich catalytically active redox couples of Ni and Co, high conductivity, and high surface area of the NCO NPs contribute to the superior electrochemical response of NCO@FTO. As an amperometric sensor, NCO@FTO detects HYA in a wide range of 10 to 4000 µM concentration with a high sensitivity of 408 μA mM−1 cm−2. The sensor has a detection limit of 0.47 μM (S/N = 3), faster response of less than 3 s, excellent selectivity, and good stability. The practical feasibility of the proposed sensor is investigated by employing it in the monitoring of real samples. This study demonstrates NCO@FTO as an efficient low-cost sensor for HYA and extends the use of spinel metal oxides in bioanalysis.
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Supercapacitors are a boon in today's modern world. The role of a supercapacitor is important in providing electrical energy in the most efficient way for the usefulness of the society. Herein, ...co-precipitation technique was adapted to prepare electrodes for energy storage and water-splitting purposes. Role of ammonia at different concentrations was deliberated. Better 269 and 364 F/g capacitance was attained for best electrode from cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) curves, respectively. The capacitive and diffusion contribution of all electrodes were estimated and found to be 91.88 and 8.12 for the best sample. A better diffusion contribution of the higher-concentration ammonia sample revealed a higher specific capacitance. In this study, 91.33% capacitive retention and 90.38% columbic efficiency were calculated after 5000 cycles of charge and discharge. Further electrochemical method like linear sweep voltammetry (LSV) and chronoamperometry (CA) was explored for water-splitting applications and 367 mA/g current density with 264 mV overpotential was achieved in the LSV plot. CA test was carried out for 10 h to reveal 189 mA/g current density and delivered 74% stability. Therefore, the present study describes different technique to extend electrochemical supercapacitor and water-splitting purposes.
•A simple co-precipitation method used to synthesis CoSn(OH)6 nanoparticles.•Higher ammonia additive revealed 269 F/g, 364 F/g from CV and GCD.•Higher ammonia additive revealed 8.12% capacitive and 91.88% diffusive contributions.•91.33% capacitive retention, 90.38% columbic efficiency was calculated over 5000 cycles.•367 mA/g current density with 264 mV over potential was achieved in LSV.
•A general expression of the diffusion indicator α for E and ECʹ reactions.•Chronoamperometry is modelled for hemispheroidal and ring electrodes.•Simple expressions of α are provided for six ...electrodes.•Planar and convergent/divergent diffusion influences are compared.
The diffusion indicator α described by Haonan and Compton (Journal of Electroanalytical Chemistry, 866(2020) 114149) is derived for hemispheroidal and ring microelectrodes. The diffusion associated with six electrodes of various geometries (microsphere, microdisc, oblate, prolate, whisker and ring) is studied using this general diffusion indicator parameter. The general parameter α is obtained from theoretical and empirical chronoamperometric current equations for E and EC′ reactions in the literature. In the various geometries, the value of the diffusion indicator and its evolution over time demonstrate the contrasting influences of planar and convergent/divergent diffusion.
Chlorambucil (CML) cures chronic lymphatic leukemia (white blood cell cancer). A high dose of CML can cause several side effects like bone marrow suppression, anemia, peripheral neuropathy, and ...infertility in the human body. In this research, we have synthesized a nanocomposite based on copper-doped titanium dioxide (CuTiO
) adorned with 2D hexagonal boron nitride (CuTiO
@BN) for the efficient electrochemical detection of CML. A series of characterization techniques FT-IR, XRD, Raman spectroscopy, SEM, TEM, EDAX XPS, and electrochemical characterization were used to analyze the CuTiO
@BN nanocomposite structural and morphological compositions. The sensing performance of the CuTiO
@BN modified GCE for CML detection has been assessed using voltammetry methods. The chronoamperometry technique analyzed the kinetics of the electrochemical oxidation of CML at CuTiO
@BN/GCE. The CuTiO
@BN-based glassy carbon electrode (GCE) has a synergetic electro-catalytic effect on CML oxidation due to its many active sites, enhanced surface area, fast charge transfer, and numerous defects. For the detection of CML, the suggested electrochemical sensor exhibits excellent selectivity, low limit of detection (LOD) as found 5.0 nM, wide linear ranges (0.02-8000 µM), and quick reaction times.
•An electrochemical immunosensor based on anti-idiotypic nanobody was devised.•The study offers a strategy for nontoxic detection using an alternative antigen.•An anti-idiotypic nanobody with ...satisfactory sensitivity was generated.•The nanosensor exhibited good detection performance in aflatoxin M1 analysis.
This study aimed to devise a nontoxic electrochemical immunosensor to quantitatively determine aflatoxin M1 by chronoamperometry with novel anti-idiotypic nanobody-functionalized screen-printed carbon electrodes (SPCEs). Anti-idiotype nanobodies (AIdnb) were developed to replace the high toxic chemically synthesized antigen. AIdnb was immobilized on the surface of SPCE via covalent coupling as capture reagent. The functionalized SPCEs were followed by characterization using electrochemical impedance spectroscopy, fourier-transform infrared spectroscopy, transmission electron microscopy mapping, and atomic force microscopy. After optimizing experimental parameters, the assembled immunosensor exhibited a good linearity range of 0.25–5.0 ng/mL, with the limit of detection of 0.09 ng/mL. The immunosensor showed a satisfactory selectivity to AFM1, without interference from analogs, including zearalenone, ochratoxin, and fumonisin B1. For practical application, the developed immunosensor was validated using real spiked samples with the recovery range 82.0%–108.0% and relative standard deviation (RSD) 10.1%–13.0%, indicating that it could be used in milk samples.
This study compares the non-enzymatic glucose sensing performance by Cu2O nanorods/nanotubes grown using electrochemically anodized Cu foam and Cu plates to form binder free one-dimensional Cu(OH)2 ...nanostructures which were subsequently annealed at higher temperatures. Resulting Cu2O nanorods/nanotubes had diameters between 100 and 200 nm and lengths in excess of 10 μm. The surface morphology and structure of these thin films studied using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy showed that the copper foam based Cu2O structures consisted of nanotubes/nanorods distributed over entire 3-dimensional space containing dense nano-pores of size ∼20 nm on outer surfaces. Cu plate based nanorods consisted of grooved macaroni type surface morphologies. Non-enzymatic glucose sensing made using chronoamperometric and cyclic voltammetric measurements showed that the Cu2O/Cu foam electrodes had a high sensitivity of 5792.7 μA mM−1 cm−2, a very low detection limit of 15 nM (S/N = 3), multi-linear detection ranges of 15 nM–0.1 μM and 575–4098.9 μM with a faster response time of less than 1 s. Cu plate based nanorods showed a sensitivity of 141.9 μA mM−1 cm−2, with a lower detection limit of 510 nM (S/N = 3). The significantly high sensitivity of Cu2O/Cu foam electrodes is attributed to the availability of increased amount of active sites due to the large effective surface area provided by Cu2O nanorods/nanotubes. The study also demonstrates the influence of the substrate on surface morphology of the nanorods/nanotubes. These Cu foam based Cu2O electrodes provide a promising platform for non-enzymatic glucose detection with high specificity and reproducibility.
In this study, we developed a sandwich aptamer-based screen-printed carbon electrode (SPCE) using chronoamperometry for the detection of cardiac troponin I (cTnI), one of the promising biomarkers for ...acute myocardial infarction (AMI). Disposable three-electrode SPCEs were manufactured using a screen printer, and various modifications such as electrodeposition of gold nanoparticles and electropolymerization of conductive polymers were performed. From the bare electrode to the aptamer-immobilized SPCE, all processes were monitored and analyzed via various techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The quantification of cTnI was conducted based on amperometric signals from the catalytic reaction between hydrazine and H2O2. The fabricated aptasensor in a buffer, as well as in a serum-added solution, exhibited great analytical performance with a dynamic range of 1–100 pM (0.024–2.4ng/mL) and a detection limit of 1.0 pM (24pg/mL), which is lower than the existing cutoff values (40–700pg/mL). Furthermore, the developed sensor showed high sensitivity to cTnI over other proteins. It is anticipated that this potable SPCE aptasensor for cTnI will become an innovative diagnostic tool for AMI.
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•Screen-printed carbon electrode (SPCE)-based aptasensor for cTnI.•Highly sensitive detection using a sandwich aptamer assay.•Robust amperometric signals from catalytic reaction between hydrazine and H2O2.•A low detection limit of 1 pM in a buffer as well as in a serum solution.•Great selectivity toward only cTnI over other proteins.
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