Cyclic Voltammetry Techniques Research Articles

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. 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 cyclic voltammetry (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.

Establishing a new efficiency descriptor for methanol oxidation reaction and its validation with commercially available Pt‐based catalysts

AbstractDirect methanol fuel cells (DMFCs) have received a lot of attention in recent years as promising technology for generating clean and efficient energy. In DMFC, the anode catalyst is a vital component because it is involved in the oxidation of methanol, which produces electrons that can be used as an energy source. Cyclic voltammetry (CV) is commonly used to test the characteristics of the electrode materials before they are employed in the actual fuel cell. Interestingly in the case of DMFCs CV also is a useful technique to obtain vital information about the performance and expected efficiency of the electrodes. In general, the CV of methanol electrooxidation for Pt‐based catalysts has two peaks, If in the forward scan (anodic scan) and Ib in the backward scan (cathodic scan). The ratio of these two peaks (If/Ib) is the most commonly used criterion for investigating CO poisoning in catalysts. However, there is a great deal of ambiguity surrounding this criterion, owing to the genesis of Ib. Addressing this we present here a new criterion to evaluate the efficiency of the catalyst using the same CV technique. We validate this newly proposed criterion with commercial Pt/C (comm. Pt/C) and other commercially available alloy catalysts.

Designing a Phenalenyl-Based Dinuclear Ni(II) Complex: An Electrocatalyst with Two Single Ni Sites for the Oxygen Evolution Reaction (OER).

A new dinuclear Ni(II) complex 1, [Ni2II(dtbh-PLY)2], is synthesized from 9-(2-(3,6-di-tert-butyl-2-hydroxybenzylidene)hydrazineyl)-1H-phenalen-1-one, dtbh-PLYH2 ligand, and structurally characterized by various analytical tools including the single-crystal X-ray diffraction (SCXRD) technique. In the solid state, both Ni(II) metal centers in complex 1 exist in a distorted square planar geometry and display the presence of rare Ni···H-C anagostic interactions to form a one-dimensional (1-D) linear motif in the supramolecular array. Complex 1 is further stabilized in the solid state by π-π-stacking interactions between the highly delocalized phenalenyl rings. The redox features of complex 1 have been analyzed by the cyclic voltammetry (CV) technique in solution as well as in the solid state, revealing the crucial involvement of both the Ni(II) metal centers for undergoing quasi-reversible oxidation reactions on the application of an anodic sweep. A complex 1-modified glassy carbon electrode, GC-1, is employed as an electrocatalyst for oxygen evolution reaction (OER) in 1.0 M KOH, giving an OER onset at 1.45 V, and very low OER overpotential, 300 mV vs the reversible hydrogen electrode (RHE) to reach 10 mA cm-2 current density. Furthermore, GC-1 displayed fast OER kinetics with a Tafel slope of 40 mV dec-1, a significantly lower Tafel slope value than those of previously reported molecular Ni(II) catalysts. In situ electrochemical experiments and postoperational UV-vis, Fourier transform infrared (FT-IR), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) studies were performed to analyze the stability of the molecular nature of complex 1 and to gain reasonable insights into the true OER catalyst.

Layer-by-layer Fabrication of Gold Nanoparticles/Polyaniline Modified Gold Electrodes for Direct Non-enzymatic Oxidation of Glucose

Background: Non-enzymatic direct glucose biofuel cell is a promising technology to harness sustainable renewable energy. Furthermore, monitoring glucose levels is essential for human lives with age. Thus, there is an increasing need to develop highly efficient and stable modified electrodes. Methods: This study reported the manufacture of gold nanoparticles/polyaniline/modified gold electrodes (Au NPs/PANI/Au electrode) based on the electrochemical polymerization method followed by the deposition of gold nanoparticles. The shapes and chemical constitution of the electrodes were examined by using different techniques including SEM, FTIR, XRD, EDS, and Raman spectroscopy techniques. The electrocatalytic efficiency of the present electrodes toward direct glucose oxidation was evaluated by applying cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry techniques. objective: fabrication of stable modified electrodes uses of the modified electrodes for renewable energy Results: The results exhibited high electrocatalytic performance for direct glucose electrooxidation in alkaline media. The modified electrodes show the ability to electrooxidation of various glucose concentrations (1 μM ̶ 100 μM) with a limit of detection and limit of quantitation of 140 nM and 424 nM, respectively. Furthermore, the Au NPs/PANI/Au electrode showed higher durability, sensitivity, and selectivity toward glucose oxidation than the Au NPs/ Au electrode, which confirmed the role of the PANI layer in enhancing the stability of the modified electrode. Conclusion: Moreover, the molar fraction of glucose to KOH has a crucial role in the output current. Hence, the modified electrodes are great candidates for direct glucose biofuel cell application. result: The electrocatalytic efficiency of the present electrodes toward direct glucose oxidation was evaluated by applying the cyclic voltammetry technique. The results exhibited high electrocatalytic performance for direct glucose electrooxidation in alkaline media. The modified electrodes show the ability to electrooxidation of various glucose concentrations (0.125M-2M). Furthermore, the Au NPs/PANI/Au electrode showed higher durability toward glucose oxidation than the Au NPs/ Au electrode, which confirmed the role of the PANI layer in enhancing the stability of the modified electrode. Moreover, the molar fraction of glucose to KOH has a crucial role in the output current.

Environmentally benign synthesis and characterization of Bi2O3‐Sb2O3 nanocomposite: Investigation of its potential as electrode material in energy storage and generation applications

A shift to alternate energy sources is needed at the present time to address rising environmental concerns. The current research work aims to use a chemical‐free and green route to synthesize nanocomposite for their application as an electrode in the generation as well as storage of energy. Subsequently, the green synthesis of Bi2O3‐Sb2O3 nanocomposite was carried out using the leaf extract of Amaranthus viridis. The synthesized nanocomposite revealed a well‐arranged pattern of spherical nanoparticles with a crystal size of 29.43 nm and a band gap value of 2.5 eV. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) potentials of Bi2O3‐Sb2O3 were studied through linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), whereas the energy storage studies were performed using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) techniques. The synthesized nanomaterial showed promising results for HER with an overpotential value of 205 mV as compared with OER, where an overpotential value of 450 mV was observed. However, excellent cyclic stability was witnessed for both reactions up to 1000 cycles. CV studies revealed an outstanding capacitance value of 348 F/g at a scan rate of 2 mV/s, whereas a specific capacitance of 269.5 F/g at a current density of 0.5 A/g was observed using GCD. The 15 h of electrode stability further endorsed the potential of synthesized material for energy‐based applications.

Comprehensive investigation on fabrication, spectral characterization and biological importance of Co(II) and Ni(II) heteroleptic complexes

Using the microwave irradiation approach, novel metallic complexes of Cobalt [Co(II)] and Nickel [Ni(II)] complexes of 2-aminothiazole (ATZ) and thiocyanate ligands [IUPAC Name: Di(2-aminothiazole) thiocyanato cobalt(II), Di(2-aminothiazole) thiocyanato nickel(II)] were created. The molecular formulas and the geometry of the complexes have been deduced by elemental analysis, molar conductance, magnetic moment, UV–visible, FT-IR, thermogravimetric analysis, cyclic voltammetry, and powder-XRD techniques. Molar conductance values indicate that the complexes are non-electrolyte (1:0) type. The complexes have octahedral structure is revealed by the magnetic moment and UV–visible spectra. The FT-IR spectra reveal that the 2-aminothiazole and thiocyanate ions are coordinated to the metal ion in a monodentate manner. The antibacterial capabilities of ligands and their Co(II) and Ni(II) compounds were studied against a restricted set of microorganisms utilizing the agar-well diffusion method and varying concentrations.When compared to free 2-aminothiazole ligand, the complexes exhibit possible activity against the fungus than bacteria. By assessing how well the complexes and ligands interact with the stable free radical DPPH, their ability to scavenge free radicals has been established. Comparing the complexes to the free ligand, the complexes exhibit greater antioxidant activity due to the fact that metal complexes are widely recognized for their capacity to accelerate medication action and boost therapeutic agent potency when they coordinate with a metal ion. The primary goal of this research is to develop multimodal medicinal drugs, which include studying the roles of 2-aminothiazole and its transition metal complexes.

Facile one step green synthesis of CdO-CdS hybrid nanocomposite: Its electrochemical and photoluminescence applications

This study reports the fabrication of a CdO-CdS hybrid nanocomposite (CDCS NC) and its application towards electrochemical sensing of dopamine (DA). The synthesis was conducted at various temperatures using Butea monosperma leaf powder as a green fuel and it was noticed in the XRD pattern that 400 °C was ideal for the formation of the CdO-CdS hybrid NC. Also, the samples were characterized by implementing Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), UV-Vis Diffused Reflectance Spectroscopy (UV-DRS) and Photoluminescence (PL) techniques. The electrochemical activity was investigated using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) techniques. A working electrode was fabricated by modifying a Glassy Carbon Electrode (GCE) using the CdO-CdS NC and it showed remarkable electrochemical activity towards dopamine (DA). Further, the electrochemical properties were investigated by varying the scan rate, pH and concentration. The fabricated electrode shows a low limit of detection of 23 µM. Hence by its unique composition and inherent properties, the NC stands as a potent tool for advancing the boundaries of electrochemical sensing, heralding a new era of innovation in sensor development.

Aminosilane assisted deposition of gold nanoparticles on Zn(OH)2 nanosheets and their application in electrochemical sensor

A facile and efficient method for systematical deposition of gold nanoparticles (AuNPs) on Zn(OH)2 nanosheets (NS) with different Zn and Au ratios was established in the presence of N-[3-(trimethoxysilyl)propyl]diethylenetriamine (TPDT silane), without adding any external reducing agents, at room temperature. Here, TPDT silane behaves as both a stabilizing and reducing agent. UV–vis absorption spectroscopy, transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy were used to confirm the formation of AuNPs on Zn(OH)2 NS. As the concentration of AuNPs increased, a proportional increase in both the number and size of deposited AuNPs on Zn(OH)2 NS was observed. To understand how the variation in the number and size of AuNPs affects their catalytic activity, the electrocatalytic activity of different composition ratios of Zn(OH)2-Au NS toward nitrite ions was studied using cyclic voltammetry and amperometric technique. The TPDT-stabilized Zn(OH)2-Au NS showed high electrocatalytic activity, attributed to the effective electron transfer from Zn(OH)2 NS to AuNPs, creating a synergistic effect that enhances the overall activity. The optimal Zn(OH)2-Au NS modified electrode showed an amperometric sensitivity of 5.72 nA/µM and a limit of detection of 1.2 µM for nitrite ions in water sample well below the guideline value of WHO. This demonstrates the practical applicability of this method for real-world water analysis.

Mo6+ bifunctional substitution of P2-type manganese oxide for high performance sodium-ion batteries

Due to its cost-effectiveness and high specific capacity, P2-type manganese (Mn) oxide is considered a highly promising cathode material for sodium ion batteries (SIBs). However, the practical application of this material is hindered by poor cyclic stability caused by the phase transition of P2-P’2 due to the Jahn-Teller effect of Mn3+ at low voltage and significant volume changes at high voltage. In this study, we utilized Mo6+ dual-function P2-Na0.67Mn0.99Mo0.01O1.997(PO4)0.0008 (NMMPO-1) to achieve exceptional magnification performance and cycle stability. Advanced electron microscopy and X-ray diffraction analysis revealed that Mo6+ acts as a pillar in replacing interlayer Na+ sites within the P2 phase, resulting in extended layer spacing and a stable crystal structure. Additionally, Mo6+ substitution for Mn3+ weakens the Jahn-Teller distortion effect of Mn3+. Ex-situ X-ray diffraction experiments demonstrated that NMMPO-1 effectively inhibits the P2-P’2 phase transition at low voltage while minimizing volume changes during charge–discharge cycles. Overall, our modified NMMPO-1 exhibits excellent cycle stability with 144.55 mA h g−1 after 100 cycles at 0.5C, retaining 83 % capacity retention rate, along with impressive rate performance achieving capacity of 100.57 mA h g−1 at 5C. Furthermore, NMMPO-1 demonstrates superior air stability compared to unmodified samples when exposed to air over multiple cycles. Moreover, through detailed analysis using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic intermittent titration technique (GITT) curves; it is observed that NMMPO-1 possesses enhanced Na+ diffusion capacity and kinetic properties compared to other materials. This research provides novel insights into the role of substituting high valence cations in layered Mn oxide materials which can contribute towards designing improved performance for future sodium ion battery applications.

Influence of phase transition with annealing temperature on structural, morphological, and supercapacitive characteristics of molybdenum oxide nanostructures

In this study, molybdenum oxide nanostructures (MoO3 NSs) were effectively synthesized through a simple, low-cost, surfactant-free, low-temperature, and scalable chemical co-precipitation method and investigated their synergistic effect with annealing temperature on energy storage applications for the first time. Herein, we have reported a phase transition of MoO3 NSs from hexagonal to orthorhombic after the annealing temperature varied from 100°C to 500°C at constant time. Additionally, the resultant NSs were thoroughly examined for their physio-chemical characteristics, which revealed the stable phase formation of the MoO3 NSs, respectively. Furthermore, the electroactive MoO3 NSs were pasted on Ni-foam substrate (M@NF), and electrochemical properties were evaluated using a three-electrode setup at room-air temperature in 1M KOH aqueous electrolyte across the potential range of 0V to 0.786V. As a result, the M@NF-5 electrode exhibited an impressive specific capacitance of 976.84Fg-1 at a scan rate of 1 Mv s-1, a higher energy density of 73.69Whkg-1, and a power density of 655Wkg-1 at 5mAg-1. The non-linear galvanostatic charge-discharge (GCD) profile aligns well with the cyclic voltammetry (CV) analysis. Both CV and GCD techniques confirm the pseudocapacitive behavior, with 83% capacitive retention observed after 2000 cycles. The fabricated symmetric device (M@NF-5//M@NF-5) exhibits enhanced electrochemical performance with a specific capacitance of 67.35Fg-1 at 5mAg-1 and with an energy density of 18Whkg-1, and a power density of 1750Wkg-1 at a specific current. These findings underscore the potential of chemically deposited α-MoO3 as an auspicious material for use in supercapacitor applications.

Facile synthesis and electrochemical investigation of graphitic carbon nitride/manganese dioxide incorporated polypyrrole nanocomposite for high-performance energy storage applications

Abstract Manganese dioxide (MnO2) nanoparticles were modified by graphitic carbon nitride (GCN) and polylpyrrole (Ppy) to enhance their electrochemical performance. The surface influence, crystalline structure, and electrochemical performance of the Ppy/GCN/MnO2 material were characterized and compared with those of pristine MnO2. It is found that surface modification can improve the structural stability of MnO2 without decreasing its available specific capacitance. The electrochemical properties of synthesized Ppy/GCN/MnO2 electrode were evaluated using cyclic voltammetry (CV) and AC impedance techniques in 5 M KOH electrolyte. Specific capacitances of 486, 815, 921, and 1377 F/g were obtained for MnO2, Ppy/MnO2, GCN/MnO2, and Ppy/GCN/MnO2, respectively, at 5 A/g. This improvement is attributed to the synergistic effect of GCN and Ppy in the Ppy/GCN/MnO2 electrode material. The Ppy/GCN/MnO2 electrode in KOH has average specific energy and specific power densities of 172 Wh kg−1 and 2065 W kg−1, respectively. Only 2 % of the capacitance’s initial value is lost after 10,000 cycles. The resulting Ppy/GCN/MnO2 nanocomposite had very stable and porous layered structures. This work demonstrates that Ppy/GCN/MnO2 nanomaterials exhibit good structural stability and electrochemical performance and are good materials for supercapacitor applications.

Enhanced pseudocapacitance performance of conductive polymer in the presence of synthesized mesoporous MnO2@Zeolite-Y

In the current study, mesoporous MnO2@Zeolite-Y (MOZ) was synthesized using the ultrasonic method. Then, MOZ was utilized to enhance the electrochemical behavior of poly ortho-aminophenol (POAP) conducting polymer. The POAP/MnO2@Zeolite-Y (MOZ/POAP) composite was synthesized by electropolymerization over the zeolite-modified working electrode surface. To investigate and compare the electrochemical behavior of the synthesized materials, two electrodes of MOZ and MOZ/POAP were designed. Subsequently, the electrochemical characteristics of the two mentioned electroactive compounds were evaluated by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests in a three-electrode setup. The comparison of the results revealed that the MOZ/POAP electrode had a more significant performance and recorded a specific capacitance (Cs) of 422 F g−1 at 1 A g−1 and cyclic stability of 97.2 % over 10,000 cycles. After verifying this electrode's remarkable efficacy, a symmetric supercapacitor of MOZ/POAP was designed and analyzed by CV and GCD techniques in a two-electrode system. This electrode revealed a Cs of 184 F g−1 at 1 A g−1, energy density of 12.02 Wh kg−1, power density of 275 W kg−1, and cyclic stability of 95.7 % over 10,000 cycles. This impressive performance was due to the presence of the manganese metal in MOZ and nitrogen and oxygen species of POAP in improving the pseudocapacitance behavior, POAP as a conductive chemical and mesoporous zeolite-Y for enhancing the electrical double-layer behavior of the electrode by providing a medium for electrochemical reactions.

Design of highly effective organic catalyst for hydrazine electrooxidation: Iodobenzo[b]furan derivatives

In this study, we investigate the electrochemical characteristics of 2-aryl/alkyl-3-iodobenzo[b]furans as anode catalysts for hydrazine (N2H4) fuel cells. Cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) techniques are employed to investigate the performance of these heteroaromatic compounds. The results demonstrate the promising potential of the 2-aryl/alkyl-3-iodobenzo[b]furans in fuel cell technology. Among the tested organic catalysts (2a, 2b, 2c, 2d, and 2e), 2a exhibited the highest electrocatalytic activity, giving a total current density of 26.62 mA/cm2 within the potential range of −0.4 to −0.8 V. 2-aryl/alkyl-3-iodobenzo[b]furans were synthesized by using palladium/copper-catalyzed Sonogashira cross-coupling reactions, followed by electrophilic cyclization with iodine (I2). All products were characterized using 1H and 13C NMR spectroscopy, confirming their structures and providing insights into their chemical properties.

Electrochemical Properties and Determination of Serotonin with Graphene/Coal Tar Pitch/Pencil Graphite Sensor Electrode using Square Wave Adsorptive Stripping Voltammetry Technique

In the present work, electrochemical and spectroelectrochemical behaviors of Serotonin (5-HT) were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Cyclic voltammetric experiments of 5-HT on graphene/coal tar pitch/pencil graphite electrode (GR/CTP/PGE) were carried out between 0.0 V and 1.8 V potential range at a scan rate of 100 mV s-1 with 20 cycles in non-aqueous media. Surface characterizations were performed using CV, EIS and scanning electron microscope (SEM). Effect of different pH values was investigated by square wave voltammetry (SWV) for determination of 5-HT. Optimization of accumulation time was determined using square wave adsorptive stripping voltammetry (SWAdSV) within potential range of -0.2 to +0.6 V. 5-HT standard solutions changing from 75 µM to 1.0 µM were prepared and the corresponding peak currents were measured. From the obtained data calibration equation was derived Ip = 0.0329C5-HT + 0.1511 with correlation coefficient (R2) 0.9958. LOD was 3.51x10-7 M and LOQ was 1.05x10-6 M.

Investigation of Electrochemical Properties and Behaviors of NBITEP Molecule; Availability of Sensor Electrode in Determination of Hg2+ with SWAdSV Technique

This Master's Thesis focuses on the synthesis and structural elucidation of 4-(2-((6-nitro-1h-benzo[d]imidazol-2-yl)thio)ethyl)phenol (NBITEP) molecule, along with its electrochemical behaviors. Electrochemical studies were carried out employing a glassy carbon (GC) electrode as the working electrode. The cyclic voltammetry (CV) technique was utilized for modification and characterization processes. Furthermore, the potential of the modified surface as a sensor electrode for Hg2+ ion detection was investigated using square wave adsorptive stripping voltammetry (SWAdSV). Detailed examinations were conducted in a phosphate buffer solution (PBS) medium specifically for Hg2+ ion detection, demonstrating the suitability of the reduced NBITEP modified GC electrode surface as a sensor electrode.

Detection of syringic acid in food extracts using molecular imprinted polyacrylonitrile infused graphite electrode

A highly sensitive, cost-effective, and reproducible electrochemical sensor has been developed using acrylonitrile (AN) molecularly imprinted polymer (MIP) over graphite (MIP-AN@G electrode) for the first time to detect phenolic compound, syringic acid (SA), in food extracts. The primary objective of the recognition of specific health-beneficial compounds like SA is to assess the overall quality of fruits and vegetables. Introducing UV–visible (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), the characterization of the fabricated MIP-AN@G electrode material has been performed. To investigate the electrode’s analytical characteristics, a tri-electrode system employing differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques was used. Rigorous analysis revealed that the electrode could exhibit high repeatability, high reproducibility, reasonably good stability, and a wide linearity window from 10 μM to 100 μM concentrations with a satisfactory lower limit of SA detection (LOD) of 0.32 μM, and a lower limit of quantification (LOQ) of 1.06 μM. The sensor’s detection competence has been further tested in cauliflower, oregano, and black olives samples, and high accuracies of over 99% were achieved in each case when compared to the high-performance liquid chromatography (HPLC) analysis. Further, the t-test statistical analysis yields satisfactory results for the SA concentrations present in the three real samples.

Triple Role of Proton Sponge (DMAN) in the Palladium-Catalyzed Direct Stereoselective Synthesis of C-Aryl Glycosides from Glycals.

The triple role of 1,8-bis(dimethylamino)naphthalene (proton sponge) as a reductant, ligand precursor, and organic base in the palladium-catalyzed Heck-type coupling reaction of glycals with aryl iodides affords the rapid and stereoselective synthesis of 2',3'-unsaturated α-C-aryl glycosides in excellent yields. The role of the proton sponge in reducing palladium(II) to (0) has been studied using cyclic voltammetry, UV-vis, HRMS, and other spectroscopic techniques. This is the first example of a palladium proton sponge complex utilized in coupling reactions. The method is observed to be tolerant of various functional groups, as demonstrated by the huge substrate scope. Moreover, the 2',3'-unsaturated α-C-aryl glycosides were also converted to 3-keto-β-C-glycosides under sterically hindered pyridinium salt catalysis via a ring-opening and -closing mechanism.

Ethylenediamine-functionalized metal-organic frameworks for applications of electrochemical supercapacitors as an additive

In this study, the impact of incorporating ethylenediamine (ED)-functionalized metal-organic frameworks (MOFs) on enhancing the electrochemical performance of polypyrrole(PPy)-based conducting polymers as supercapacitor electrode materials was investigated. The stability of terephthalic acid-containing MOFs in different environments, including exposure to acids, relies on the specific metal ions and ligands utilized in their construction. In this research, ED treatment was chosen for its resistance to acid attack. Unlike the post-synthetic modifications observed in previous literature regarding ED-modified MOF5, this study introduces a unique approach where ED is directly integrated into the framework in a single step. The resulting materials, referred to as ED-MOF, were employed in creating a novel composite material concurrently with polypyrrole, designed for use as electrode materials in supercapacitor applications. The optimal loading in the electrochemical preparation of polypyrrole-based conducting polymers was determined using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Areal capacitance for the resulting electrodes was evaluated through cyclic charge-discharge experiments. The areal capacitance of the ED-ZnMOF/1@/PPy/PGE electrode was found to be 575.2 mF.cm−2 at a charge/discharge current density of 1 mA.cm−2. This research underscores the potential advantages of combining conducting polymers and metal-organic frameworks in supercapacitors, as well as other electrochemical systems.

Microliquid/Liquid Interfacial Sensors: Biomimetic Investigation of Transmembrane Mechanisms and Real-Time Determinations of Clemastine, Cyproheptadine, Epinastine, Cetirizine, and Desloratadine.

Antihistamines relieve allergic symptoms by inhibiting the action of histamine. Further understanding of antihistamine transmembrane mechanisms and optimizing the selectivity and real-time monitoring capabilities of drug sensors is necessary. In this study, a micrometer liquid/liquid (L/L) interfacial sensor has served as a biomimetic membrane to investigate the mechanism of interfacial transfer of five antihistamines, i.e., clemastine (CLE), cyproheptadine (CYP), epinastine (EPI), desloratadine (DSL), and cetirizine (CET), and realize the real-time determinations. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques have been used to uncover the electrochemical transfer behavior of the five antihistamines at the L/L interface. Additionally, finite element simulations (FEMs) have been employed to reveal the thermodynamics and kinetics of the process. Visualization of antihistamine partitioning in two phases at different pH values can be realized by ion partition diagrams (IPDs). The IPDs also reveal the transfer mechanism at the L/L interface and provide effective lipophilicity at different pH values. Real-time determinations of these antihistamines have been achieved through potentiostatic chronoamperometry (I-t), exhibiting good selectivity with the addition of nine common organic or inorganic compounds in living organisms and revealing the potential for in vivo pharmacokinetics. Besides providing a satisfactory surrogate for studying the transmembrane mechanism of antihistamines, this work also sheds light on micro- and nano L/L interfacial sensors for in vivo analysis of pharmacokinetics at a single-cell or single-organelle level.

Development of a highly sensitive non-enzymatic electrochemical cholesterol biosensor based on Ag with Cu2O nanomaterial deposited on TiO2 nanotubes

We developed a highly sensitive non-enzymatic biosensor based on hybrid Ag-Cu2O@TNTs nanostructure aggregate for the detection of cholesterol. A facile anodization process on a thin titanium alloy (Ti6Al4V) plate was achieved to deposit TiO2 nanotubes (TNTs). Subsequently, TNTs was decorated with Cu2O nanomaterials (NM) using wet chemical bath deposition (CBD) technique. The electro-deposition of silver (Ag) nanoparticles on Cu2O@TNTs hybrid aggregate produced high electroactive surface area which enhanced the electron transfer rate. The structure of Ag-Cu2O@TNTs was examined using X-ray diffraction (XRD), transmission emission microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV) and amperometry techniques were utilized to study the electrochemical behaviour of nanostructures. The hybrid nanostructure demonstrated great sensitivity (12140.06 μAmM−1cm−2) compared to pure TNTs and Cu2O@TNTs with low detection limit (0.057 mM) and fast response. This study highlights exciting potential of nanocomposites in advancement of reproducible and selective biosensor applications.