Anodic Peak Research Articles

Synthesis, intercalation reactions, and electrochemical studies for VO2/PEO/Chitosan

VO2 obtained by hydrothermal synthesis from V2O5 was used as a matrix to obtain hybrid compounds containing different proportions of polyethylene oxide and chitosan. The XRD results demonstrate that monoclinic VO2 was obtained, and hybrid compounds showed variation in the displacement of the lamella peak, indicating an intercalation of polymers into the matrix. The stretching and vibration bands show a variation towards higher wavelength values of the hybrid compounds, which indicates that the intercalation of the polymers occurred into the matrix. The UV–Vis spectra show the absorptions that can be attributed to the transitions of each material. Absorption in the visible region decreases for hybrid compounds in relation to VO2. The hybrid compounds presented lower bandgap values compared to VO2. From cyclic voltammetry, it was possible to observe anodic and cathodic peaks linked to the redox process of the VIV/VIII pair for both VO2 and VO2/polymers, which is derived from the insertion/disinsertion process of lithium ions, where the hybrid compound presented a different voltammetric profile compared to VO2. The total charge curves as a function of the number of cycles demonstrate better cycling stability and a greater total charge of the hybrid compounds compared to VO2. These results demonstrate that hybrid compounds have potential as cathode materials for lithium-ion batteries.

Investigation on the Potential of Some N-phenylalkanehydrazides as Superoxide Anion Radical Scavengers and Glutathione Peroxidase Binders with ADME Prediction: Comparison with Vitamin C

Objective: An investigation on the antioxidant activity and ADME properties of some N-phenylalkanehydrazides (NPhs) in comparison with ascorbic acid was carried out. Materials and Methods: The power of the compounds to scavenge the superoxide anion radical was examined using cyclic voltammetry. Furthermore, molecular docking was used to examine how NPhs bind to the antioxidant enzyme glutathione peroxidase (GPx). Finally, ADME properties were predicted using the SwissADME webserver. Results: The results showed that the studied compounds had significantly higher EC50 values than Vitamin C and displayed spontaneous binding with GPx with binding energy similar to ascorbic acid. Also, substantial values emerged from the predictive analysis of drug-likeness and bioavailability characteristics. Discussion: First, the EC50 of the compounds under study was determined by assessing the decrease in the anodic current peak intensity; this demonstrated significant radical scavenging activity. Next, the electrostatic way of binding with ROS radical and with antioxidant enzyme was disclosed by the binding free energies; however, the oxygen and nitrogen atoms in the compounds' structures might make many conventional hydrogen bonds with amino acids. Finally, NPh (a) followed all the rules for drug-likeness and bioavailability estimates, making it a promising moiety for synthesising new antioxidant chemicals. Conclusion: The current study is a hybrid of experimental and computational methods that complement each other perfectly.

Para-Hydroxy Ni(II)-POCOP Pincer Complexes as Modifiers on Carbon Paste Electrodes and Their Application in Methanol Electro-Oxidation in Alkaline Media

The application of organometallic materials as anodes in fuel cell devices has experienced a notable increase in recent years. However, the use of POCOP pincer complexes remains scarcely explored despite their great relevance in catalysis. Thus, in this work, the electrocatalytic activity to methanol in alkaline media of three Ni(II)-based POCOP pincer complexes—[NiCl{C6H2-4-OH-2,6-(OPiPr2)2}] (a1), [NiCl{C6H2-4-OH-2,6-(OPtBu2)2}] (a2), and [NiCl{C6H2-4-OH-2,6-(OPPh2)2}] (a3)—will be discussed. The complexes were use as modifiers of carbon paste electrodes that were evaluated using cyclic voltammetry considering diverse factors, such as the absence and presence of MeOH, diverse proportions (% w/w) of the complex in the electrode, scan rate, and different MeOH concentrations. Results indicated the presence of a redox pair Ni(II)/Ni(III) with a quasi-reversible behavior in all complexes, the anodic peak currents of which were proportional to the increase in MeOH concentrations (0.05–0.3 mM), and their oxidation potentials varied in the function of the P-substituent in the Ni(II)-POCOPs backbone. Complex a1 exhibited the best current density (429.5 mA cm2 at 0.5 mM) compared to its analogs a2 and a3. The current intensity of all electrodes displays good stability, which remains—with slight changes—up to 100 s. Moreover, a comparison of their catalytic rate constants suggested a great activity in complex a1 (0.52 × 106 cm3 mol−1 s−1) compared to its analogues, implying a great activity in the electro-oxidation of MeOH. Hence, this work opens new opportunities for the electrochemical application of POCOPs complexes for future DMFCs development.

Evaluation of Transducer Elements Based on Different Material Configurations for Aptamer-Based Electrochemical Biosensors.

The selection of an appropriate transducer is a key element in biosensor development. Currently, a wide variety of substrates and working electrode materials utilizing different fabrication techniques are used in the field of biosensors. In the frame of this study, the following three specific material configurations with gold-finish layers were investigated regarding their efficacy to be used as electrochemical (EC) biosensors: (I) a silicone-based sensor substrate with a layer configuration of 50 nm SiO/50 nm SiN/100 nm Au/30-50 nm WTi/140 nm SiO/bulk Si); (II) polyethylene naphthalate (PEN) with a gold inkjet-printed layer; and (III) polyethylene terephthalate (PET) with a screen-printed gold layer. Electrodes were characterized using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to evaluate their performance as electrochemical transducers in an aptamer-based biosensor for the detection of cardiac troponin I using the redox molecule hexacyanoferrade/hexacyaniferrade (K3[Fe (CN)6]/K4[Fe (CN)6]. Baseline signals were obtained from clean electrodes after a specific cleaning procedure and after functionalization with the thiolate cardiac troponin I aptamers "Tro4" and "Tro6". With the goal of improving the PEN-based and PET-based performance, sintered PEN-based samples and PET-based samples with a carbon or silver layer under the gold were studied. The effect of a high number of immobilized aptamers will be tested in further work using the PEN-based sample. In this study, the charge-transfer resistance (Rct), anodic peak height (Ipa), cathodic peak height (Ipc) and peak separation (∆E) were determined. The PEN-based electrodes demonstrated better biosensor properties such as lower initial Rct values, a greater change in Rct after the immobilization of the Tro4 aptamer on its surface, higher Ipc and Ipa values and lower ∆E, which correlated with a higher number of immobilized aptamers compared with the other two types of samples functionalized using the same procedure.

Sensitive detection of uric acid based on low-triggering-potential cathodic luminol electrochemiluminescence achieved by ReS2 nanosheets.

The majority of previously reported cathodic electrochemiluminescence (ECL) systems often required very negative potential to be carried out, which hasgreatly limited their applications in the sensing field. Screening high-performance cathodic ECL systems with low triggering potential is a promising way to broaden their applications. In this work, rhenium disulfide nanosheets (ReS2 NS) have been revealed as an efficient co-promoter to realize low-triggering-potential cathodic luminol ECL. One strong cathodic ECL signal appeared at a potential of -0.3V and one anodic ECL peak was obtained at -0.15V under the reverse potential scan, which were caused by electrogenerated reactive oxygen species (ROS) from hydrogen peroxide. The generation of strong luminol ECL at low potential was the result of the electrocatalytic effect of ReS2 NS on the reduction of H2O2. The scavenging effect of uric acid (UA) on the ROS could significantly inhibit the cathodic ECL. As a result, an ECL sensor was proposed, which showed outstanding performance for the detection of UA in the range of 10nM to 0.1mM with a low detection limit of 1.53nM. Moreover, the ECL sensor was successfully applied in the sensitive detection of UA in real samples. This work provides anew avenue to establish a low-potential cathodic ECL system, which will sufficiently expand the potential application of cathodic ECL in the sensing field.

Synthesis of platinum-nickel nanoparticles supported by carbon and titanium oxide structures for efficient and enhanced formic acid oxidation

In this study, Platinum Nickel (PtNi) nanoparticles was synthesized using the chemical reduction method and functionalized multi-walled carbon nanotube (f-MWCNT) was synthesized by handling multi-walled carbon nanotube (MWCNT) with weak acid using the arc discharge method. To be evaluated in formic acid oxidation, f-MWCNT supported by PtNi (PtNi@f-MWCNT) and titanium oxide (TiO2) supported by PtNi (PtNi@TiO2) catalysts were synthesized using chemical reduction method. The comparison of PtNi, PtNi@f-MWCNT, and PtNi@TiO2 catalysts obtained in the study for formic acid oxidation is presented and their characterizations were carried out by X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), and Fourier Transform Infrared Spectrometer (FTIR). According to TEM results; PtNi, PtNi@f-MWCNT, and PtNi@TiO2 particle sizes were found to be 12.00 nm, 7.37 nm, and 5.38 nm, respectively. According to the CV results obtained for formic acid oxidation, the anodic peak peaks for PtNi, PtNi@f-MWCNT, and PtNi@TiO2 were 61.20 mA.cm−2, 80.17 mA.cm−2 and 65.07 mA.cm−2, respectively. These results showed that the addition of f-MWCNT and TiO2 support exhibited 1.30 and 1.06 times higher electrocatalytic activity for formic acid oxidation and higher resistance to CO poisoning with If/Ib ratios of 0.97 and 1.48, respectively. With the long-term stability tests obtained, it was observed that the f-MWCNT-supported catalyst showed approximately 9 times more current at the end of 5000 s and provided faster charge transfer with EIS. These findings demonstrated that a more cost-effective catalyst with high electrocatalytic activity was synthesized by obtaining f-MWCNTs from MWCNTs using the arc discharge method. It has also been revealed that TiO2 and f-MWCNT supports exhibit very high potential for fuel cell applications.

Electrochemical Detection of Heavy Metal Ions using Gold Nanoparticles on Carbon Dots Extracted from Curry Leaves

Carbon dots (CDs) have attracted attention due to their versatility in electronic and optical properties based on precursor and type of synthesis process. Recently, many researchers have focused on using natural resources or wastes to form CDs. Four samples of CDs have been synthesized from curry leaves using a microwave-assisted approach at heating powers of 700 and 800 V with durations of 5 and 8 minutes. UV-Vis and FTIR spectra reveal the existence of carbon graphitic elements with carboxyl and hydroxyl functional groups on the surfaces of CDs. CVs of AuNPs/CDs/GS electrodes in ferricyanide disclosed that as-synthesized CDs produced using a lower heating power of 700 W exhibit pronounced electrocatalytic activity with sluggish electron transfer kinetics. Conversely, as-synthesized CDs created with a higher heating power of 800 W demonstrate reduced electrocatalytic activity but rapid electron transfer kinetics. Electrochemical detection of Pb2+ ions was observed through a sharp peak around -0.42 to -0.438 V, while detection of Hg2+ ions was observed through two anodic peaks around +0.334 to +0.408 V during a forward scan in acetate buffer (pH 4.5) on AuNPs/CDs/GS electrodes when tested individually. These distinct peaks also appeared in mixture solutions, with a slight reduction in peak current density that suggests the selectivity of the AuNPs/CDs/GS electrodes towards Pb2+ and Hg2+ ion detection. The optimum AuNPs/CDs/GS electrode for sensitive and selective detection of Pb2+ and Hg2+ was recorded using CDs D as a functional supporting matrix for AuNPs that was synthesized using a heating power of 800 W for 8 minutes.

Synthesis, Spectroscopic, and DFT Studies of Vanadium (III) Hydroxamate Complex with Potential Biological Applications

A new vanadium (III) hydroxamate complex of composition V(4- NO2C6H4CH=CHCONHO)3 has been synthesized by reaction of VCl3 with potassium salt of 4-nitrocinnamohydroxamate (4-NO2C6H4CH=CHCONHO) in 1:3 molar ratio in dry methanol solvent. The newly synthesized complex is characterized by elemental analysis, molar conductivity, magnetic moment measurements and IR, UV-Vis spectral studies and mass spectrometry. DFT calculations were carried out by using Orca 4.2.1 program and the negative values of the energies of EHOMO and ELUMO for the V(III) complex confirm its stability. A distorted-octahedral geometry around vanadium center has been suggested for complex based upon physicochemical, spectroscopic and DFT studies, involving bonding through hydroxylamine and carbonyl oxygens (O O coordination). The cyclic voltammogram of the complex shows single anodic and cathodic peak. The TGA/DTA curve indicates the single step decomposion of complex. The biological potential of the ligand and complex have been tested by in vitro antimicrobial studies and cytotoxicity assay. Antimicrobial activity of complex has been found increased as compare to precursor and ligand. The results of cytotoxicity reveal the complex less toxic as compared to standard drug simvastatin.

2D-network of boron-functionalized N-doped graphene quantum dots for electrochemical sensing of dopamine

A glassy carbon electrode (GCE) modified by boron-functionalized N-doped graphene quantum dots (B-GQDs) was employed for the electrochemical determination of dopamine (DA), a neurotransmitter. The B-GQDs were obtained by hydrothermal etching of GO with H2O2 and NH3 in the presence of H3BO3. By using various techniques, including transmission electron microscopy, atomic force microscopy, molecular absorption spectrometry, fluorescence, ICP-MS, and zeta potential analysis, it was demonstrated that B-GQDs are self-organized in 2D-network, being N-doped GQDs nanoparticles crosslinked by H3BO3. The GCE modification was carried out using the drop-casting method with B-GQDs in Nafion®, previously dispersed through ultrasonication. For the first time, the synthesized nanomaterial was tested in the electroanalysis of neurotransmitters. The B-GQDs/Nafion®/GCE modification led to a significant increase in peak currents in the presence of DA. The electrochemical and interfacial characteristics of the sensors were evaluated by cyclic voltammetry (CV). Under optimized square wave voltammetry and supporting electrolyte conditions, a linear dependence between the anodic peak current and DA concentration was observed in the range of 0.7 to 188 μmol L−1 (R2 = 0.9991). The limit of detection (LOD) was estimated at 0.05 μmol L−1. Selectivity was confirmed in the presence of potential interferents found in urine, with interference response below 12 %. The sensor exhibited excellent intra-day and inter-day repeatability, with a relative standard deviation of 4.12 % and 4.66 %, respectively. Electrochemical determination of DA was conducted in artificial urine samples (Surine®), with recovery values of 90–101 %. The new analytical platform B-GQDs/Nafion®/GCE demonstrated promising characteristics for application in biological and/or pharmaceutical analysis.

Electrochemical Determination of Uric Acid Using a Nanocomposite Electrode with Molybdenum Disulfide/Multiwalled Carbon Nanotubes (MoS2@MWCNT).

This paper presents an application for a molybdenum disulfide nanomaterial with multiwalled carbon nanotubes (MoS2@MWCNT/E) in a modified electrode substrate for the detection of uric acid (UA). The modified electrode generates a substantial three-fold increase in the anodic peak current for UA compared to the unmodified MWCNT electrode (MWCNT/E). The MoS2@MWCNT/E surface was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS). The achieved detection limit stood at 0.04 µmol/L, with a relative standard deviation (RSD) of 2.0% (n = 10). The method's accuracy, assessed through relative error and percent recovery, was validated using a urine standard solution spiked with known quantities of UA.

Sensitive Voltammetric Detection of Acetaminophen on CuONPs-MWCNTs Modified Glassy Carbon Electrode with Enhancement Effect of Anionic Surfactant

In the present work, a voltammetric method using differential pulse voltammetric technique for the assessment of antipyretic and analgesic drug, acetaminophen was developed. The CuO nanoparticles were prepared and characterized. A glassy carbon electrode (GCE) fabricated with the suspension of CuO nanoparticles (CuONPs) and multi-walled carbon nanotubes (MWCNTs) were used. The modified electrode showed improved anodic peak current by introducing an anionic surfactant sodium dodecyl sulphate in phosphate buffer solution. The consequence of pH of supporting electrolyte, amount of nanoparticles suspension and surfactant concentration was investigated at a physiological pH of 7.4. Using differential pulse voltammetry, the fabricated electrode showed linear dynamic range from 9 to 160 nM of acetaminophen concentration. From the calibration plot, the computed detection limit was 5.06 nM and quantification limit was 16.88 nM. The developed method was checked for its reproducibility and assay during a day and intraday as well. The developed process was fruitfully applied to detect acetaminophen in pediatric oral suspensions administered to infants.

Synthesis, structural characterisations, electrochemical behavior and antibacterial activities of a chromium(III) resorcinolate complex

The integration and implementation of transition metal complexes as working electrode for surface modifications has become an area of research interest now a days. Based on this, a novel anionic complex having a formula of Na3[Cr(HR)4Cl2] (HR- = resorcinolate) with octahedral geometry, was prepared and characterized by elemental analysis, molar conductance, vibrational spectra. Electropolymerization of the ligand, salt, and complex was done on glassy carbon electrodes with effective surface area 0.15, 0.17, and 0.2 cm2 for poly(NaHR)/GCE, Cr(0)/GCE, and poly(Na3[Cr(HR)4(Cl2)]/GCE respectively. The presence of a redox polymer film on the surface of the electrode was indicated by the experimental changes observed for a solution containing Na3[Cr(HR)4Cl2]. Specifically, the anodic peak currents, which represent the oxidation process, showed significant increases at different potential values compared to the ligand and salt. These potential values were approximately + 114 mV and + 573 mV. Additionally, the cathodic peak current, which is corresponding to the reduction process, exhibited changes at − 230 mV as the scan cycles were increased. These variations strongly suggested the formation of a film composed of a redox polymer on the electrode's surface. Further, the resistance to charge transfer (Rct) of the compound is in the lower voltage compared to the free ligand, CrCl3•6H2O, and the unmodified GCE. This indicates that the modified compound exhibits improved conductivity due to its reduced charge transfer resistance. The antibacterial activity assessed against two Gram-positive bacteria strains (Staphylococcus aureus and Streptococcus epidermis) and two Gram-negative bacteria strains (Escherichia coli and Klebsiella pneumoniae), indicate that the Cr(III) complex exhibit higher antibacterial activity compared to the ligand and the metal salt but lower than the reference. The synthesized is a highly conductive material suitable for potential applications in sensors and catalysis, especially in situations that require efficient and rapid electron transfer process

Synthesis, characterisation and voltammetric study of dimethylammonium lead iodide perovskite

In the last decade, the most investigated perovskite materials are the hybrid organic-inorganic perovskites (HOIPs) due to their optoelectronic properties and possible application in the production of photovoltaics. This interest has led to an ongoing search for new HOIP variants, alongside thorough investigations of the properties of existing HOIPs. That is why our research in the field of organic-inorganic perovskites is aimed at the synthesis, characterization, and investigation of the electrochemical properties of dimethylammonium lead iodide (DMAPbI3) using voltammetric studies. A modified synthesis of DMAPbI3, differing slightly from the one described in the literature, was performed by combining stoichiometric amounts of lead iodide (PbI2) and dimethylammonium iodide (DMAI) dissolved in acetonitrile. After conducting controlled evaporation, a yellow crystalline powder of DMAPbI3 was obtained. The identity and purity of the obtained compound were confirmed by powder X-ray diffraction (PXRD), infrared (IR) and Raman spectroscopy, and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Investigations on the electrochemical properties of DMAPbI3 by cyclic voltammetry were performed with dichloromethane (DCM) and tetrabutylammonium chloride (TBAC) as the electrolyte. A paraffin-impregnated graphite electrode (PIGE) was used as a working electrode, on which the perovskite microparticles were immobilized. The electrochemical activity of DMAPbI3 is recognized through an intense, broad, and irreversible anodic peak attributed to the oxidation of the constituents to different possible products and the decomposition of the perovskite structure.

A green perspective for the first electrochemical detection and application of balsalazide via recycled waste core-shell carbon/CdO nanoparticles-based hybrid nanosensor

In this report, a glassy carbon electrode (GCE) modified with carbon-based core–shell structures (CSC) with CdO nanoparticles has been prepared and performed for the electrochemical detection of Balsalazide (BLZ). The electrochemical investigation of BLZ was carefully examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on the bare GCE, and CSC-CdO/GCE. Compared to bare GCE, the proposed CSC-CdO/GCE sensor can remarkably enhance the electrocatalytic activity towards the oxidation of BLZ with an increase in the anodic peak currents. For the optimum of experimental conditions, the influence of supporting electrolyte, the pH, concentration of the nanosensor, and scan rate on the peak potentials and current were investigated on the current response of BLZ before the electrochemical determination of BLZ in commercial human serum and urine samples for GCE, and CSC-CdO/GCE. The limit of detection (LOD) for BLZ in the linear range of 8.00 × 10−9 – 8.00 × 10−5 mol/L was determined as 2.20 × 10−9 mol/L. Recovery measurements assessed the accuracy of the proposed sensor in serum and urine samples. The developed sensor indicated high sensitivity and great stability toward BLZ. Core-shell structures are frequently preferred in sensor applications due to their perfect shapes, active catalytic sites, rapid interfacial transport of pores at different length scales, and their ability to reduce or shorten diffusion action paths. CSC was used as a modification material in this study due to its superior properties and advantages. Since CSC has a high surface area during the electron transfer process, it enables more efficient charge transfer between the electrode and the electrolyte. In the study, CdO nanoparticle modification on the CSC was ensured for a synergistic effect to enhance the surface area, electroactivity, and selectivity. After morphological, physical, and chemical characterization of composite material, electrochemical experiments showed that it is extremely promising because of its wide linear concentration range, low LOD, and nearly no interference with some interfering compounds and ions.

Design of an Insulin Tracer Protein-Based Biosensor for Insulin Determination

Aim: The regulation of blood glucose levels is controlled by insulin, which is produced by the pancreatic beta system. Inadequate synthesis of beta insulin, results in elevated glucose levels, a condition known as diabetes, which can lead to various chronic health issues. In recent times, the diagnosis of diabetes, particularly type 1, has shifted towards the direct measurement of insulin levels. To facilitate this, an immunosensor was created to enable rapid and sensitive examination of insulin levels, with the goal of improving the quality for life for diabetic patients. Material and Method: For this purpose, an insulin tracer protein based biosensor was designed for the determination of insulin at all solutions. For determination of insulin, electrobiochemical analyses were performed. Optimisation and characterisation studies were performed using differential pulse voltammetry. The performance of bioelectrochemical system was analysed by Receiver Operating Characteristic method. Results: The insulin biosensor cyclic woltammogram was obtained between -0,1 and 0,6 V potantial. At 0,45 V was found as the anodic peak side for determination the insulin. Optimisation and characterisation studies performed at 0,45 V with differential pulse voltammetry. Conclusion: The study successfully identified stable and easy-to-use insulin concentrations, indicating the potential of the newly developed immunosensor for applications in clinical biochemistry laboratories.

Electrochemical Sensing of Phenylbutazone using Multi-Walled Carbon Nanotube Paste Electrode in Pharmaceutical and Biological Fluids

The electrochemical performance of phenylbutazone (PBZ) was studied using a multi-walled carbon-nanotube-modified paste electrode (MWCNT/CPE) using a variety of voltammetric tools like cyclic voltammetry (CV), linear sweep voltammetry (LSV), and square wave voltammetry (SWV). The results showed that the MWCNT/CPE exhibited remarkable electro-catalytic action towards the electrochemical oxidation of PBZ in a phosphate buffer solution of physiological pH 7 compared to a bare carbon paste electrode. The electro-kinetic parameters like heterogeneous rate constant, transfer coefficient, scan rate, pH, and involvement of electrons in electro-oxidation of PBZ was investigated. For bare CPE, the peak current was noted to be 19.53 μA with peak potential of 0.6871 V. For MWCNT/CPE, the peak current was 30.53 μA with peak potential of 0.6792 V. The anodic peak was analyzed, and the process was diffusion controlled. For the estimation of PBZ, a SWV technique was developed with great precision and accuracy, with a detection limit of 5.2 nM and a limit of quantification of 17 nM, in the concentration range 1 × 10−7 to 10 × 10−6 M. The MWCNT/CPE has been used successfully for PBZ detection in injection, blood, and urine samples, with recovery rates of 98.9% to 101.5%, 96.3% to101.7% and 98.3% to 102.8%, respectively.

Novel disposable screen-printed sensors based on copper oxide nanoparticles for sensitive voltammetric assay of antazoline

The fabrication and electroanalytical validation of a novel homemade screen-printed carbon electrode enriched with copper oxide nanoparticles (CuONPs/SPCEs) were demonstrated for sensitive and selective voltammetric determination antazoline (ANT) in eye drop solution and spiked serum samples. With a reported electrocatalytic activity, CuONPs catalyzed the oxidation of ANT at the electrode surface showing an irreversible anodic oxidation peak at 0.9 V under a diffusion-controlled electrode reaction. Based on the electroanalytical and molecular orbital calculation studies, oxidation of ANT molecule undergoes via oxidation of the aliphatic nitrogen atom within the ANT moiety. Linear calibration curves were illustrated covering the ANT concentration ranged from 0.01 to 3.819 µg mL−1 with and limit of detection 3 ng mL−1. The fabricated sensors enriched with CuONPs exhibited high fabrication and measurement reproducibility with a prolonged shelf lifetime (6 months). The electroanalytical approach presented adequate sensitivity and selectivity with a short analysis time, applying low-cost instrumentation and simple pretreatment protocol avoiding handling hazardous organic solvents. Trace ANT was monitored in the presence of different interfering species, degradation products, and xylometazoline hydrochloride (ZYL) in the co-formulated ophthalmic pharmaceutical samples. The CuONPs based voltammetric sensors were introduced as a reliable eco-friendly analytical tool for monitoring ANT in ophthalmic solutions and biological fluids with acceptable recovery values.

New type nanocomposite based on metal-organic frameworks decorated with nickel nanoparticles as a potent electrocatalyst for methanol oxidation in alkaline media

Methanol oxidation reaction (MOR) is used to provide electrical energy via direct methanol fuel cell (DMFC), which requires a practical design of electrocatalysts to accelerate the sluggish MOR. In this study, we successfully fabricated the carbon black nanoparticles/graphite ceramic electrode (CBNPs/GCE) supported metal-organic frameworks (MOFs) and decorated with nickel nanoparticles (NiNPs) as a new type nanocomposite modified electrode (NiNPs/MOFs/CBNPs/GCE) via a chemical and an electrochemical process, respectively. The surface morphology and structure of the synthesized nanocomposite materials and modified electrodes were characterized using field emission scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. Then, the NiNPs/MOFs/CBNPs/GCE was used as a non-platinum electrocatalyst for electrocatalytic oxidation of methanol in alkaline media. The obtained results show the efficient electrocatalytic activity of the NiNPs/MOFs/CBNPs/GCE toward the MOR with high anodic peak current density (Jpa = 34.8 mA cm−2) compared with the other prepared electrocatalysts; MOFs/CCE, NiNPs/CCE, MOFs/CBNPs/GCE, NiNPs/CBNPs/GCE, and NiNPs/MOFs/CCE, due to the synergistic effect of nanocomposite components; NiNPs, MOFs and CBNPs. The prepared electrocatalyst; NiNPs/MOFs/CBNPs/GCE, not only shows a high electrochemically active surface area (ECSA = 2.15 cm2) but also has long-term durability in MOR. In general, it can be said the NiNPs/MOFs/CBNPs/GCE is a promising candidate for application in DMFC.

Enhancing hydrogen storage capacity: MWCNT-infused Mg–Ti alloy synthesized via mechanical alloying

Scientists are currently more interested in carbon allotropes since they are still having significant challenges in employing metal hydrides to achieve high hydrogen storage capacities. Mg–Ti alloy was created via mechanical alloying with MWCNT added. XRD confirms that the Mg–Ti solid solution exists. The existence of carbon in the Mg–Ti alloy was further validated by Raman analysis. The TEM investigation reveals that the electron diffraction measurements for the samples prior to hydrogenation have d spacing values of 2.3, 1.44, and 1.0,. The corresponding planes for these values are the (103) and (201) planes of the Mg–Ti intermetallic alloy of the FCC phase, as well as the CNTs plane of (002). In thermal analysis, as the exothermic peak dropped from 355.1 °C to 346 °C, in the same way that the activation energy dropped from 277.38 kJ/mol to 82.7 kJ/mol. The cyclic voltammetry examination of the Mg–Ti alloy with 4 wt% MWCNT added reveals a distinct anodic peak at −0.54 V. The calculated Cdl value for the Mg67Ti29MWCNT4 alloy in the impedance spectroscopy investigation is 2.372 F. Following the addition of MWCNT to the Mg–Ti alloy, the CR rate similarly decreased from 0.1728 to 0.1614 mgpy. Higher absorption capacity of 815 mAhg−1 and very long stable cycle life is demonstrated by the 4 wt% MWCNT added Mg–Ti.

Ultrasonic synthesis of borophene as a 2D electrode material with high electrocatalytic activity for use in fuel cell applications

Green energy systems must be able to provide a significant proportion of the energy needed to meet the ever-increasing demand for energy. Fuel cells are a promising solution to bridge the gap in the green energy transition. This study aims to enhance the energy efficiency of fuel cells by utilizing 2D supported nanocatalysts in the anode compartment. Borophene was synthesized using the liquid phase exfoliation method to be used as a support structure due to its superior properties. To use borophene as a supporting material in methanol fuel cells, a borophene-palladium hybrid structure (Pd@Borophene) was prepared using the chemical reduction method. The scanning electron microscopy (SEM) images showed that the obtained particle had a partially formed layered structure. The electrocatalytic activity of the Pd@Borophene was investigated through anodic reactions in Direct Methanol Alcohol Fuel Cells (DMFC). Electrochemical analyses were conducted to compare the effect of borophene on Pd and Pd@borophene nanocatalysts on the anodic reaction. The anodic peak current value of methanol oxidation for Pd@borophene was found to be 24.3 mA/cm2, which is approximately four times higher than that of unsupported Pd nanoparticles. Additionally, the ratio of forward current (If) to reverse current (Ib), which serves as an indicator of catalyst poisoning, was determined to be 2.27. This study contributes significant findings to the literature by demonstrating that borophene, an advanced 2D material, can be synthesized using a low-cost liquid phase exfoliation method and can be utilized in fuel cell applications for energy generation.