Electrocatalysis最新文献

A unique and irregular form distorted Cu₂(V₂O₇) sphere with crumbled sheets of rGO nanocomposite was developed as a sensor over a glassy carbon electrode (GCE). It showed a higher sensitivity for an antipsychotic drug, pimozide (PMZ). Voltammetric techniques were used to investigate the electrochemical behavior of PMZ. The formation of Cu₂(V₂O₇)-rGO nanocomposite was confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to examine the surface morphology and its properties. Cyclic voltammetric studies revealed that PMZ displayed intense electrocatalytic activity and exhibited an electro-oxidation peak at the modified electrode. The modified electrode possessed unique qualities such as fast electron transfer ability, repeatability, and reproducibility. The proposed differential pulse voltammetric (DPV) and square wave voltammetric (SWV) methods showed linearity in the concentration range of 5.12 × 10⁻⁹ M to 3.06 × 10⁻⁴ M and 1.02 × 10⁻⁹ M to 5.30 × 10⁻⁴ M, respectively. The limit of detection (LOD) was calculated to be 1.70 × 10⁻¹⁰ M and 8.52 × 10⁻¹¹ M, while the limit of quantification (LOQ) was found to be 5.66 × 10⁻¹⁰ M and 2.84 × 10⁻¹⁰ M, respectively, for DPV and SWV methods. The developed methods were successfully applied for the determination of PMZ in pharmaceutical formulations and human urine samples.

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The Co₂O₃-Chitosan composite (Co@Chitosan) nanoparticles were synthesized through a green approach. The composite under investigation was characterized by various analytical methods, including scanning electron microscopy (SEM), transmitted electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) confirming the preparation step. The modified composite’s performance was evaluated for its potential applications in nitrite sensing and hydrogen production by utilizing diverse electrochemical methodologies. The Co₂O₃-Chitosan that has been modified exhibits a linear detection range of 0.25–100 µM and a limit of detection (LOD) of 0.117 µM with a response time of approximately 5 s using the amperometry technique. Furthermore, the utilization of Co₂O₃-Chitosan composite as a proficient catalyst for hydrogen generation in an alkaline environment was implemented. The electrode exhibited enduring stability in fuel generation and heightened energy safeguarding. The current density of the electrode was observed to attain a value of (upeta) ₅₀ at − 0.55 and − 0.43 V (versus RHE) for Co₂O₃ and Co@Chitosan, respectively. The study investigated the durability of electrodes during extended periods of constant potential chronoamperometry lasting 6 h. The Co₂O₃ and Co@Chitosan exhibited a reduction in initial current by 11% and 7%, respectively.

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In recent years, the development of highly sensitive and selective electrochemical sensors has been a pivotal area of research, driven by the growing demand for environmental monitoring and industrial process control. Among various materials investigated for sensor applications, manganese oxide (MnO₂) nanoparticles have garnered significant attention due to their excellent electrochemical properties, environmental friendliness, and natural abundance. Critical analyses of the synthesis of MnO₂ using different techniques such as hydrothermal method, chemical precipitation, and sol–gel process which allows for the fine-tuning of particle size and morphology while enhancing the electrochemical sensing capabilities have been reviewed. The review also provides a comprehensive overview of the recent advancement evaluation of manganese oxide-based electrodes for detecting sulfonamides and other analytes in water across diverse matrices. This paper sets the stage for a comprehensive exploration of the synthesis methods and application areas of MnO₂ nanoparticles in electrochemical sensors, highlighting their role in advancing sensor technology and their impact on various sectors.

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Dopamine (DA) is a neurotransmitter secreted by the brain that plays a variety of roles in the central nervous system. An imbalance in dopamine can cause a range of disease symptoms and negative effects, such as Parkinson’s disease and arrhythmia. Detecting DA accurately and rapidly is therefore crucial for medical diagnosis and disease prevention. In this study, PVP and rGO-MWCNTs were encapsulated via a hydrothermal method to form a composite material. The composite was then characterized by scanning electron microscopy (SEM). The three materials were combined, and on this basis, a new DA electrochemical sensor was constructed. Notably, the high specific surface area and high conductivity of the rGO-MWCNTs cooperate with the amphiphilic and stable dispersion of PVP, which further improves the electrocatalytic activity of the sensor for DA. Under optimal conditions, the DA content is detected within a wide range and has a low detection limit, which can be explained by the electrochemical redox process of the sensor. In addition, the sensor shows satisfactory recovery and accuracy in detecting the DA content in real human serum samples via the standard addition method.

Triclosan, like many other aromatic halides, plays an important role industrially and inevitably ends up in the environment. Chemical treatments have effectively mitigated the presence of such chemicals, through using harsh oxidizing treatments, which are not without issues. A milder and greener alternative, such as an electrochemical method, is needed for the mitigation of compounds, such as triclosan. Herein, we evaluated triclosan treatment via electrochemical cycling and compared it to a traditional chemical oxidative process. Cyclic voltammetry was carried out using a three-electrode cell containing glassy carbon, silver wire, and platinum wire in organic solvent. Electrochemical cycling revealed 6 × greater triclosan conversion compared to traditional chemical oxidation reaction, as monitored by UV–Vis spectroscopy. In terms of reaction product selectivity, the chemical and electrochemical reactions yielded the oxidized triclosan and an ether cleavage product, dichlorophenol, as determined by gas chromatography–mass spectrometry. Of note, the chemical oxidation yielded the chlorinated re-dimerization side product, which was not observed during electrochemical cycling, which is beneficial, as such products have to be degraded again. Overall, our findings indicate that electrochemical methods offer significant advantages over traditional organic methods, such as product selectivity, relative conversion, and greener operation. In addition, electrochemical approaches offer tunability, such as electrode material, electrolyte, solvent, potential, or current applied, all of which may be integrated into a more efficient environmental application.

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The research focuses on creating an innovative graphitic carbon nitride electrochemical sensor (g-C₃N₄) for the precise and sensitive detection of the antiviral medication valganciclovir (VCR), also known as Valcyte. VCR is an antiviral medication used to treat diseases, including CMV retinitis, and to protect transplant patients against CMV infection by stopping the virus from spreading. This drug is typically given to patients with weak immune systems, HIV/AIDS, and organ transplants. Though VCR provides numerous benefits, it must be administered with caution as it can cause allergic reactions and renal damage. A modified carbon paste electrode called g-C₃N₄/CPE has demonstrated remarkable electrocatalytic activity in oxidizing varying levels of chlorine radiation. Various methods were employed to characterize the created g-C₃N₄, including field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and Raman and Fourier transform infrared (FT-IR). The sensor has a detection range of 1 to 16 µM, which makes it more sensitive than traditional drug detection techniques. It can detect as low as 0.88 × 10⁻⁸ M under ideal experimental conditions. The sensor’s ability to identify VCR using g-C₃N₄ was tested using amperometric i-t curve analysis. The EIS (electrochemical impedance spectroscopy) was employed to investigate the electrochemical features of many electrodes. The comparable R_ct values were 3114 Ω, 13,770 Ω, and 3794 Ω for g-C₃N₄/CPE, bare GCE, and bare CPE, respectively. During the test, various commonly used interferents and drugs were introduced to the VCR solution to examine the influence of foreign interferents on the outcomes. Various electrokinetic factors were examined to explore the electrochemical behavior of VCR. Environmental monitoring, drug analysis, and clinical diagnostics benefited from successfully using the generated g-C₃N₄/CPE. Additionally, it can play a vital role in creating new and efficient methods for antiviral drug VCR determination.

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A composite containing silver nanoparticles embedded Mn-MOFs has been synthesized using a simple solvothermal route. The composite-modified electrode has been utilized in the simultaneous measurement of purine base pairs of DNA [guanine (GU), adenine (AD)] and uric acid (UA). The morphology of the composite has been studied by scanning electron microscopy which revealed that the Ag nanoparticles homogeneously get distributed over the layers of Mn-MOFs. The thermal stability of the composite has been studied by thermogravimetric analysis. BET adsorption–desorption isotherm study revealed the large surface area and mesoporous nature of the composite. The electrochemical behavior of the composite material has been studied through impedance spectroscopy, cyclic voltammetry (CV), and square wave voltammetry (SWV) techniques to decipher the redox nature of it towards the target analytes like GU, AD, and UA. Each of these analytes has displayed a distinct catalytic oxidative signal with well-resolved peaks during their simultaneous measurement. The linearity obtained for UA, GU, and AD by square wave voltammetry is in the concentration range of 0.5–280 µM with a limit of detection of 64.49, 78.84, and 125.33 nM, respectively. The composite-modified electrode has been successfully applied to real sample matrices like human serum, urine, and commercially available fish sperm DNA samples. The fabricated sensor showed very good responses to these analytes from real sample matrices with prolonged stability and reproducibility.

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It is of key importance to design efficient insulin electrocatalysts based on nonprecious noble metal-free. However, the design of advanced nanostructured based metal phosphides is scarcely reported. In this work, for the first time, a novel insulin sensor based on Ni₂P electrode materials with nanoplate structure was designed. In this regard, Hofmann-type coordination polymers (HCPs) based on Ni(H₂O)₂[Ni(CN)₄]·H₂O (Ni–Ni HCP) were prepared and used as precursors to the preparation of Ni₂P. The unique layer structure of Ni–Ni HCP precursors can lead to the preparation of Ni₂P nanoplates with large surface areas, high availability of active catalytic centers, and abundant interior space for fast diffusion and boosted reaction kinetics. The electrochemical results showed that the Ni₂P nanoplates offer excellent capability toward insulin oxidation in 0.1 M NaOH electrolyte solution. Moreover, a proper linear relationship was obtained between insulin concentrations and the current responses in the range of 10 to 100 pM with the detection limit of 3 pM and with good capability for the determination of insulin in the human blood serum sample. This work offers a rational method for the structure engineering of Ni₂P nanoplates using HCP precursors, which can lead to the fabrication of high-performance insulin sensor.

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In situ synthesis of novel hybrid organic–inorganic nanopetals (HNPs) of Copper (Cu²⁺) and gold-conjugated hemoglobin (Au@Hb) is reported. The presence of Au within the protein matrix prevents the formation of a flower-like assembly of the formed nanopetals of Au@Hb and Cu²⁺ via the co-precipitation method. Morphological, chemical, and electrocatalytic activities of in situ synthesized Au@Hb-Cu HNPs were examined systematically. The hybrid nanopetal (Au@Hb-Cu HNP)-modified screen-printed PET electrodes show enhanced electrocatalytic activity toward the oxidation of H₂O₂ compared to electrodes modified with Hb-copper hybrid nanoflowers (Hb-Cu HNFs) without Au conjugation. The proposed biosensor exhibits excellent electrochemical performance with broad linear responses over a H₂O₂ concentration ranging from 5 to 1000 µM (R² = 0.99) and showed a lower detection limit of 1.46 µM at 0.30 V vs. pseudo Ag/AgCl. Enhanced electrochemical performance is attributed to heterogeneous active sites over hybrid nanopetal surfaces. Moreover, the hybrid nanopetal–modified electrodes showed excellent stability and anti-interference performance in the presence of ascorbic acid, uric acid, fructose, and glucose. These results demonstrate that Au@Hb-Cu HNPs offer a better and more promising alternative for the electrochemical detection of H₂O₂ sensitively.

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