Diffusion-controlled Mechanism Research Articles

Characterization and Dissolution Mechanism of Low-Molecular-Weight Organic Acids or Inorganic Mesoporous Particle-Based Piperine Amorphous Solid Dispersions.

The objective of the current study is to prepare amorphous solid dispersions (ASDs) containing piperine (PIP) by utilizing organic acid glycyrrhizic acid (GA) and inorganic disordered mesoporous silica 244FP (MSN/244FP) as carriers and to investigate their dissolution mechanism. The physicochemical properties of ASDs were characterized with scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) and one-dimensional proton nuclear magnetic resonance (1H NMR) studies collectively proved that strong hydrogen-bonding interactions formed between PIP and the carriers in ASDs. Additionally, molecular dynamic (MD) simulation was conducted to simulate and predict the physical stability and dissolution mechanisms of the ASDs. Interestingly, it revealed a significant increase in the dissolution of amorphous PIP in ASDs in in vitro dissolution studies. Rapid dissolution of GA in pH 6.8 medium resulted in the immediate release of PIP drugs into a supersaturated state, acting as a dissolution-control mechanism. This exhibited a high degree of fitting with the pseudo-second-order dynamic model, with an R2 value of 0.9996. Conversely, the silanol groups on the outer surface of the MSN and its porous nanostructures enabled PIP to display a unique two-step drug release curve, indicating a diffusion-controlled mechanism. This curve conformed to the Ritger-Peppas model, with an R2 > 0.9. The results obtained provide a clear evidence of the proposed transition of dissolution mechanism within the same ASD system, induced by changes in the properties of carriers in a solution medium of varying pH levels.

Formulation and Characterization of Isoconazole Loaded Invasomal Gel for Effective Antifungal Activity

The characterization of isoconazole invasomal gel formulations (IG1–IG5) aimed to evaluate their physical attributes, drug content, and drug release kinetics for topical application. All formulations exhibited transparency and smooth texture, indicating uniform drug dispersion. While IG1 had an easily pourable consistency, IG4 displayed very good consistency, suggesting viscosity differences. Despite these variations, all formulations showed good homogeneity and high drug content, with IG4 leading in drug content percentage. Spreadability and viscosity varied among formulations, influencing ease of application and adherence to the skin. Cumulative drug release profiles revealed sustained release over 12 hours, with notable differences in release rates and extents among formulations. IG4 exhibited the most sustained release, aligning with pharmacokinetic requirements for antifungal therapy. Its release profile followed a diffusion-controlled mechanism, with a high cumulative drug release percentage of 98.95 ± 0.32% over 12 hours. Antifungal activity against Candida albicans was comparable to Isoconazole, suggesting IG4’s effectiveness in treating fungal infections. Stability studies confirmed the formulation’s stability under tested conditions, supporting its potential for further development and clinical use.

Formulation and Characterization of Isoconazole Loaded Invasomal Gel for Effective Antifungal Activity

The characterization of isoconazole invasomal gel formulations (IG1–IG5) aimed to evaluate their physical attributes, drug content, and drug release kinetics for topical application. All formulations exhibited transparency and smooth texture, indicating uniform drug dispersion. While IG1 had an easily pourable consistency, IG4 displayed very good consistency, suggesting viscosity differences. Despite these variations, all formulations showed good homogeneity and high drug content, with IG4 leading in drug content percentage. Spreadability and viscosity varied among formulations, influencing ease of application and adherence to the skin. Cumulative drug release profiles revealed sustained release over 12 hours, with notable differences in release rates and extents among formulations. IG4 exhibited the most sustained release, aligning with pharmacokinetic requirements for antifungal therapy. Its release profile followed a diffusion-controlled mechanism, with a high cumulative drug release percentage of 98.95 ± 0.32% over 12 hours. Antifungal activity against Candida albicans was comparable to Isoconazole, suggesting IG4’s effectiveness in treating fungal infections. Stability studies confirmed the formulation’s stability under tested conditions, supporting its potential for further development and clinical use.

Characterizing of a unique Al/Cu FGMMC fabricated via the ARB-CRB process followed by annealing

This study investigates the influence of different annealing temperatures on the microstructure and growth of the intermetallic phase in an Al/Cu functionally graded metal matrix composite (FGMMC ( produced by the accumulative roll bonding (ARB)-cold roll bonding (CRB) process. SEM images show the evolving distribution of Cu content in the composite, with the finest and thinnest Cu layer observed in the Al/20Cu region. The annealing at 400°C and 450°C for 2, 4, and 6 hours results in the formation of intermetallic layers (Al2Cu, Al4Cu9, and AlCu) with a clear progression from the Al side to the Cu side, as confirmed by SEM-EDS and TEM analysis. Increasing the annealing conditions increases the thickness of the intermetallic layers. In addition, the intermetallic layers are thicker in the FGMMC sample than in the ARB sample under the same conditions due to the additional strain during the process. The findings demonstrate that a diffusion-controlled mechanism governs the growth of the Al2Cu, Al4Cu9, and AlCu layers. The tensile test results indicate that as the Cu content increases from 20 wt% to 80 wt%, the ultimate tensile strength of the layers increases from 288.24 MPa to 373.66 MPa, while the elongation decreases from 8.2 % to 5.3 %. After annealing, however, these values decreased due to the restoration phenomenon and intermetallic formation. The fracture surface predominantly exhibits a brittle mode, especially with increasing Cu content and annealing conditions.

Utilizing rare earth titanates to improve performance of solid-state electrochromic device

Exploring new materials and synthesis recipes are required to enhance the electrochromic performance especially, when used in solid-state devices. Here, polycrystalline gadolinium titanate (Gd2TiO5 or GTO), synthesized using a simple solid-state reaction method, has been used for this purpose by combining it with polythiophene (P3HT). The electrochemical investigation of the Gd2TiO5 doped P3HT electrode has been carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which reveals the dominance of diffusion-controlled mechanism over charge storage on the electrode surface as compared to the P3HT electrode. The Gd2TiO5 doped P3HT solid-state electrochromic device shows color modulation at 515 nm and 670 nm wavelengths with a color contrast of as high as 79% and 42%, respectively, under an external bias of as low as ±1.4 V. The prepared device switches between maroon to a transparent state in less than a second under the external bias (±1.4 V) with a high coloration efficiency of 346 cm2/C. The device shows improved cycle life over 100 switching cycles at both the wavelengths, which makes it more suitable for real-life applications.

Modulating charge storage mechanism of cobalt-tungsten nitride electrodes using in situ formed metal-p-n heterojunction for ultrahigh energy density supercapattery

Supercapatteries combine both diffusion-controlled and capacitive charge storage mechanisms to simultaneously deliver exceptional power density and energy density. Though developing materials that combine both charge storage mechanisms for use as supercapattery electrodes is difficult, one solution has been to modify a material that inherently has one of these mechanisms so that it also exhibits the other form of charge storage. In the present study, we modulate the electrochemical reconstruction of a W5N4 electrode to modify its charge storage from pure battery-type to pseudocapacitive, thus enhancing its specific capacity and cyclic stability. This modulation was carried out by embedding Co in W5N4 (Co-W5N4), leading to the formation of W and N-doped Co(OH)2 as an active phase and producing a high specific capacity of 2211 C g−1 at 2 A g−1. The incorporation of a thin layer of TiO2 (Co-W5N4/TiO2) through atomic layer deposition minimized tungsten dissolution during reconstruction, thus generating in-situ a dynamic metal–p-n junction heterostructure (Co-W5N4||Co(OH)2||TiO2) that modulated the charge flow, achieving high-rate capability (retaining 53.1 % at 50 A g−1 compared to 2 A g−1) and cyclic stability (82.8 % after 100,000 cycles at a high current density of 40 A g−1). As illustrated by operando electrochemical impedance spectroscopy and physicochemical analysis, the dynamic response of metal–p-n junction sustains the pseudocapacitive charge storage mechanism at high current rate. This study thus demonstrates the formation of metal-p-n heterojunction and describes its dynamic response under actual charge/discharge operating conditions, providing useful information for the design of energy storage electrodes and energy conversion catalysts.

Eco-friendly synthesis of cluster-like Dy2Ce2O7 nanoparticles using orange juice and their application in electrochemical determination of isoniazid

In this study, cluster-like (CL) Dy2Ce2O7 nanoparticles were synthesized via an easy and rapid sonochemical pathway. X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) were used for the characterization of nanoparticles. The construction of an electrochemical sensor was performed to determine isoniazid (IZN) based on ionic liquid (IL) and the cluster-like nanostructure of Dy2Ce2O7 modified carbon paste electrode (CL-Dy2Ce2O7/IL/CPE). Using the fabricated sensor, cyclic voltammetry (CV) along with differential pulse voltammetry (DPV) have been utilized to examine the catalytic activity of the modified electrode toward oxidation of IZN in 0.1 M phosphate buffer solution (PBS) with pH of 7.0. The large specific surface area and electrocatalytic properties of CL-Dy2Ce2O7 as well as the good electrical conductivity of ionic liquid greatly enhanced the current signal of the IZN at the CL-Dy2Ce2O7/IL/CPE. The process at the surface of the electrode was under the diffusion control mechanism and the diffusion coefficient for IZN was 1.08 × 10−5 cm2/s. Additionally, with a low detection limit of 9.0 nM, the peak current of IZN rose linearly with concentration in the range of 0.02–340.0 μM. Our findings demonstrate that the sensitive and selective detection of IZN in pharmaceutical and biological samples can be achieved using the CL-Dy2Ce2O7/IL/CPE.

A Review of Recent Advancements in Nanotechnology for Medical Drugs Delivery

In recent years, nanotechnology has played a crucial role in revolutionizing the delivery of drugs by allowing precise control of the release and targeting of the drugs. During this review, we will discuss some of the recent advances in nanotechnology for drug delivery systems, as well as strategies used for delivering targeted drugs, controlled release mechanisms, as well as the potential applications of nanotechnology for specific diseases. Among the strategies discussed for targeting drug delivery are ligand-targeted nanoparticles, size-dependent nanoparticles, magnetic nanoparticles, pH-responsive nanoparticles, antibody-targeted nanoparticles, active targeting using peptides that penetrate cells, and surface charge-based strategies. In addition to degradation-controlled release mechanisms, diffusion-controlled release mechanisms are also used as well as pH-controlled release mechanisms, magnetism-controlled release mechanisms, light-controlled release mechanisms, and temperature-controlled release mechanisms. The discussion also includes nanotechnology's potential to treat diseases, including cancer, heart disease, and neurological disorders. This is in addition to its potential applications in general. In order to improve patient outcomes, these advances in nanotechnology have the potential to revolutionize medicine in order to provide targeted and controlled release drug delivery systems that can revolutionize the way medicines are delivered to patients.

Capacitive-Controlled Prussian White with a Nickel Iron Hexacyanoferrate Composite Cathode for Rapid Sodium Diffusion.

Prussian blue analogues receive tremendous attention owing to their spacious three-dimensional skeleton, high theoretical specific capacity, facile synthesis procedure, and high cost-effectiveness as among the most promising candidates for cathode materials in sodium-ion batteries (SIBs). Nonetheless, the practical specific capacity, especially under high current, is particularly frail due to the sluggish ion diffusion. In this study, the strategy of Ni substitution and formation of water-coordinated Fe is applied to lower the crystal field energy and elevate the active low-spin (LS) Fe content, which leads to a capacitive sodium storage mechanism, resulting in a substantial specific capacity under high current density. The delivered specific capacity of PW-325@2NiFe-55 is 95 mAh g-1 at 50 C, which is 72.5% capacity retention of the one at 0.5 C. Also, it maintains 80.2% of its initial specific capacity after 500 cycles at 5 C. Furthermore, a hypothesis of a joint diffusion-controlled and capacitive mechanism for high-spin (HS) Fe and a mere capacitive mechanism for LS Fe is put forward and verified through potentiastatic tests, operando 57Fe Mössbauer spectroscopy, and ex situ XRD, which provides a new horizon to enhance the electrochemical performance for SIBs.

Regulating Drug Release with Microspheres: Formulation, Mechanisms, and Challenges

Controlled drug release is a critical component of current drug delivery systems, aiming to improve therapeutic efficacy while minimizing negative effects. Because of their tunable features and numerous applications, microspheres have emerged as adaptable carriers for achieving controlled medication release. This review paper delves into the formulation techniques, mechanisms, and issues connected with controlling drug release utilizing microspheres. The essay begins by discussing the importance of controlled medication release in healthcare and the critical role that microspheres play in accomplishing this goal. It then looks into the numerous formulation options for microspheres, including material selection, production processes, and drug inclusion techniques. The impact of microsphere properties such as particle size, shape, and drug loading on release kinetics is also thoroughly examined. The processes influencing drug release from microspheres are described in detail, including diffusion-controlled, erosion-controlled, and swelling-controlled release mechanisms and the interaction of polymer characteristics and drug-polymer interactions. The article looks at sophisticated methods for producing targeted drug release, including exterior stimuli-responsive microspheres and internal stimuli-responsive systems. Site-specific targeting strategies are investigated, including passive targeting via the increased permeability and retention (EPR) effect and active targeting via ligand-functionalized microspheres. Despite its promise, microsphere-based drug delivery systems face a number of obstacles. Major challenges are burst release, stability, scale-up, immunogenicity, and regulatory issues. In the context of microsphere-based drug delivery, recent advances in enhanced characterization techniques, nanotechnology integration, combination therapies, personalized medicine, and new trends are discussed.

Opto-electrochemical variation with gel polymer electrolytes in transparent electrochemical capacitors for ionotronics

Advanced flexible ionotronic devices have found excellent applications in the next generation of electronic skin (e-skin) development for smart wearables, robotics, and prosthesis. In this work, we developed transparent ionotronic-based flexible electrochemical capacitors using gel electrolytes and indium tin oxide (ITO) based transparent flexible electrodes. Different gel electrolytes were prepared using various salts, including NaCl, KCl, and LiCl in a 1:1 ratio with a polyvinyl alcohol (PVA) solution and compared its electrochemical performances. The interaction between gel electrolytes and ITO electrodes was investigated through the development of transparent electrochemical capacitors (TEC). The stable and consistent supply of ions was provided by the gel, which is essential for the charge storage and discharge within the TEC. The total charge contribution of the developed TECs is found from the diffusion-controlled mechanism and is measured to be 4.59 mC cm−2 for a LiCl/PVA-based gel. The prepared TEC with LiCl/PVA gel electrolyte exhibited a specific capacitance of 6.61 mF cm−2 at 10 μA cm−2. The prepared electrolyte shows a transparency of 99% at 550 nm and the fabricated TEC using LiCl/PVA gel exhibited a direct bandgap of 5.34 eV. The primary benefits of such ionotronic-based TEC development point to its potential future applications in the manufacturing of transparent batteries, electrochromic energy storage devices, ionotronic-based sensors, and photoelectrochemical energy storage devices.

Novel Deliberately Sensitive and Selective Tetrahydrozoline Voltammetric Sensors Integrated with a Copper Oxide Nanoparticle/Zeolite Platform.

The present study introduced a novel disposable screen-printed carbon electrodes (SPCEs) modified with copper oxide/zeolite nanostructures for eco-friendly selective differential pulse voltammetric quantification of tetrahydrozoline (THZ) in eyedrop samples and biological fluids. Modification of the electrode matrix with copper oxide nanoparticles/zeolite nanostructures (CuONPs/ZY) with their effective and synergistic electrocatalytic activity enhanced the electrode performance against electrooxidation of THZ at 0.960 V in BR at pH 9.0 with a diffusion-controlled reaction mechanism. The tentative oxidation mechanism based on molecular orbital calculations postulates the oxidation of THZ molecules through oxidation of a nitrogen atom five-membered ring and the participation of two electrons/protons in the electrode reaction. Linear calibration curves were illustrated within a wide THZ concentration range from 0.24 to 57.2 μg mL-1 recording a limit of detection (LOD) value of 0.0799 μg mL-1. The CuONPs/ZY/SPEs exhibited improved performance compared with the sole reported THZ sensor-based gold film-plated carbon paste electrodes, in addition to their high reproducibility of fabrication and measurement and prolonged shelf lifetime. Tetrahydrozoline was successfully assayed in the presence of excipients, degradation products, and chloramphenicol. The presented voltammetric sensor can be considered as an eco-friendly and reliable analytical approach for monitoring THZ residues in eye drop samples and biological fluids with high recovery compared with the official pharmacopeial analytical protocol. The presented sensors were assessed according to an EcoScale tool and also compared with the reported THZ sensor.

Preparation and Evaluation of Sustained Release Matrix Tablets of Acelofenac and Comparision of Formulated and Marketed Product

The aim of performing this study is to develop matrix tablet to improve the dissolution rate of aceclofenac and release the drug in a controlled manner over a period of 24 hours. Matrix tablets of aceclofenac, using various viscosity of hydrophilic polymer HPMC in two different proportions, hydrophobic polymer ethyl cellulose and Guar gum were prepared by wet granulation method and subjected to in vitro drug release studies. Tablets were evaluated for in vitro drug release profile in phosphate buffer with pH 7.5. The thickness and hardness of prepared tablets were 3.8 ± 0.2 to 3.9 ±0.2 mm and 4 ± 3 to 5 ± 3 kg/cm2, respectively. The friability was within the acceptable limits of pharmacopeial specifications (0.31 to 0.71%), which indicates the good mechanical strength of the tablets. The in vitro drug release from the proposed system was best explained by Higuchi’s model, indicating that drug release from tablets displayed a diffusion-controlled mechanism. Based on the study results, formulation F7 was selected as the best formulation.

A Nanocomposite Dynamic Covalent Cross-Linked Hydrogel Loaded with Fusidic Acid for Treating Antibiotic-Resistant Infected Wounds.

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high levels of morbidity and is considered a difficult-to-treat infection, often requiring nonstandard treatment regimens and antibiotics. Since over 40% of the emerging antibiotic compounds have insufficient solubility that limits their bioavailability and thus efficacy through oral or intravenous administration, it is crucial that alternative drug delivery products be developed for wound care applications. Existing effective treatments for soft tissue MRSA infections, such as fusidic acid (FA), which is typically administered orally, could also benefit from alternative routes of administration to improve local efficacy and bioavailability while reducing the required therapeutic dose. Herein, we report an antimicrobial poly(oligoethylene glycol methacrylate) (POEGMA)-based composite hydrogel loaded with fusidic acid-encapsulating self-assembled polylactic acid-b-poly(oligo(ethylene glycol) methyl ether methacrylate) (PLA-POEGMA) nanoparticles for the treatment of MRSA-infected skin wounds. The inclusion of the self-assembled nanoparticles (380 nm diameter when loaded with fusidic acid) does not alter the favorable mechanical properties and stability of the hydrogel in the context of its use as a wound dressing, while fusidic acid (FA) can be released from the hydrogel over ∼10 h via a diffusion-controlled mechanism. The antimicrobial studies demonstrate a clear zone of inhibition in vitro and a 1-2 order of magnitude inhibition of bacterial growth in vivo in an MRSA-infected full-thickness excisional murine wound model even at very low antibiotic doses. Our approach thus can both circumvent challenges in the local delivery of hydrophobic antimicrobial compounds and directly deliver antimicrobials into the wound to effectively combat methicillin-resistant infections using a fraction of the drug dose required using other clinically relevant strategies.

Corrosion mitigation behavior of mild steel in supercritical CO2 environments with varying the solution volume

The corrosion behavior of X70 steel in CO2 saturated water at 60 °C and 10 MPa was investigated by limiting the exposed solution volumes. When the specific solution volume to the exposed area was smaller than 10 mL/cm2, it revealed the formation of protective FeCO3 layer, leading to a significant corrosion reduction. The time-sensitive nucleation and the spatial growth of FeCO3 grains governed the overall performance of corrosion product layers. The solution volume dependency was further explained by a diffusion-controlled deposition mechanism. It suggested a possible way to prevent CO2 corrosion in harsh environments by generating stable FeCO3 layers.

Oxygen Vacancies Driven by Co in the Deeply Charged State Inducing Intragranular Cracking of Ni-Rich Cathodes.

Intragranular cracking within the material structure of Ni-rich (LiNixCoyMn1 - x - y, x≥0.9) cathodes greatly threatens cathode integrity and causes capacity degradation, yet its atomic-scale incubation mechanism is not completely elucidated. Notably, the physicochemical properties of component elements fundamentally determine the material structure of cathodes. Herein, a diffusion-controlled incubation mechanism of intragranular cracking is unraveled, and an underlying correlation model with Co element is established. Multi-dimensional analysis reveals that oxygen vacancies appear due to the charge compensation from highly oxidizing Co ions in the deeply charged state, driving the transition metal migration to Li layer and layered to rock-salt phase transition. The local accumulation of two accompanying tensile strains collaborates to promote the nucleation and growth of intragranular cracks along the fragile rock-salt phase domain on (003) plane. This study focuses on the potential risks posed by Co to the architectural and thermal stability of Ni-rich cathodes and is dedicated to the compositional design and performance optimization of Ni-rich cathodes.

A study on the first hydrogenation behavior of TiFe0.9Cr0.1 hydrogen storage alloy with the laves phase

This study investigated the first hydrogenation behavior of TiFe-based hydrogen storage alloy with the laves phase. A TiFe0.9Cr0.1 alloy was prepared through vacuum arc melting, and it had a dual-phase microstructure with B2 and laves phases. The first hydrogenation kinetics was measured by applying a hydrogen pressure of 40 bar at 30 °C, where the alloy absorbed hydrogen without thermal activation. The first hydrogenation kinetics was divided into three sections to understand the first hydrogenation behavior, and each section was analyzed using a solid–gas reaction model. The model's goodness of fit was evaluated by fitting each section. In the early hydrogen absorption stage, a surface-controlled mechanism (Chemisorption model) was analyzed to be the most dominant. In the second stage, where hydrogen was quickly absorbed, an interface-controlled mechanism (CV3D model) was most suitable. In the last hydrogen absorption stage, where hydrogen absorption was saturated, a diffusion-controlled mechanism (GB3D model) was most suitable.

Cobalt-nickel phosphide supported on reduced graphene oxide for sensitive electrochemical detection of bisphenol A

Bisphenol A (BPA) is a commonly utilized phenolic contaminant in several manufacturing processes, contributing to environmental pollution. Therefore, the detection of BPA holds significant importance for monitoring water quality. In this work, we report a robust electrochemical detection method for BPA utilizing cobalt−nickel bimetal phosphide nanoparticles (CoNiP) supported on reduced graphene oxide (rGO). The CoNiP@rGO-modified glassy carbon electrode exhibits remarkable electrochemical activity in BPA detection. The detection mechanism is controlled by adsorption-mediated electron transfer, showcasing a low limit of detection (LOD) at 0.38 nM and a high sensitivity of 96.4 A M−1 cm−2 within the linear range of 0.001–8 μM. Furthermore, our developed sensor demonstrates good reproducibility and successfully detected BPA in actual water samples. The electrochemical activity of CoNiP@rGO was also characterized for hydroquinone (HQ) detected through a diffusion-controlled mechanism, displaying an excellent sensitivity of 36.4 A M−1 cm−2 across a broad linear range. These findings underscore the promising potential of CoNiP@rGO as a candidate for electrochemical detection of phenolic contaminants, especially in the sensing of BPA in environmental water samples. This efficacy is attributed to the modulation of its electronic properties, combined with its large electroactive surface area and low electron-transfer resistance.

Ni0.5Co0.5S nano-chains: a high-performing intercalating pseudocapacitive electrode in asymmetric supercapacitor (ASC) mode for the development of large-scale energy storage devices.

Grid-scale energy storage solutions are necessary for using renewable energy sources efficiently. A supercapattery (supercapacitor + battery) has recently been introduced as a new variety of hybrid devices that engage both capacitive and faradaic charge storage processes. Nano-chain architectures of Ni0.5Co0.5S electrode materials consisting of interconnected nano-spheres are rationally constructed by tailoring the surface structure. Nano-chains of the bimetallic sulfide Ni0.5Co0.5S are presented to have a superior charge storage capacity. The Ni0.5Co0.5S nano-chain electrode presents a capacitance of 2001.6 F g-1 at 1 mV s-1, with a specific capacity of 267 mA h g-1 (1920 F g-1) at 1 A g-1 in 4 M KOH aqueous electrolyte through the galvanostatic charge-discharge (GCD) method. The reason behind the high charge storage capacity of the materials is the predominant redox-mediated diffusion-controlled pseudocapacitive mechanism coupled with surface capacitance (electrosorption), as the surface (outer) and intercalative (inner) charges stored by the Ni0.5Co0.5S electrodes are close to 46.0% and 54.0%, respectively. Additionally, a Ni0.5Co0.5S//AC two electrode full cell operating in asymmetric supercapacitor cell (ASCs) mode in 4 M KOH electrolyte exhibits an impressive energy density equivalent to 257 W h kg-1 and a power density of 0.73 kW kg-1 at a current rate of 1 A g-1.

Sensitive determination of 4,6-dinitro-o-cresol based on a glassy carbon electrode modified with Zr-UiO-66 metal-organic framework entrapped FMWCNTs.

A DNOC electrochemical sensor has been developed by using a composite of Zr-UiO-66 and FMWCNTs on a glassy carbon electrode (GCE) and using the differential pulse voltammetry technique. The synthesized materials were physico-chemically characterized by BET, PXRD, FTIR, TGA, EDX, and FESEM. Cyclic voltammetry showed that DNOC has three oxidation peaks at 0.03 V (RSD: 0.23%), 0.42 V (RSD: 0.21%), and 1.32 V (RSD: 0.32%) and three reduction peaks at - 0.20 V (RSD: 0.15%), - 0.82 V (RSD: 0.26%), and - 1.14 V (RSD: 0.19%) which follow a diffusion-controlled mechanism. Different parameters were optimized using differential pulse voltammetry and good linear ranges were found for the simultaneous detection of the three reduction peaks. For a specific concentration range of 0.1-50 μM, a limit of detection of 0.119 μM based on 3Sb/m was obtained. The interfering effects of five non-phenolic pesticides and five heavy metals were evaluated to highlight the selectivity of the developed sensor. It is the first report of an electrochemical DNOC sensor in which all three oxidation peaks are prominently visible. Ethion and chloropyriphos were found to inhibit the redox process of DNOC on the developed sensor platform Zr-UiO-66/FMWCNT/GCE. The sensor was successfully applied to DNOC determination in spiked potato samples and the results showed a standard deviation of less than 3%. The proposed method is expected to provide a novel platform for the quantitative determination of DNOC pesticides in vegetables.