Electrocatalysis最新文献

A highly sensitive MWCNTs paste electrode (MWCNTPE) modified with chitosan-nickel complex (Chit-Ni²⁺) was designed for the efficient electrochemical determination of uric acid (UA). The MWCNTPE surface is drop-coated with the Chit-Ni²⁺ complex. The electroanalytical performance of Chit-Ni²⁺ complex modified MWCNTPE toward UA is thoroughly analyzed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Experimental results reveal that Chit-Ni²⁺ complex modified MWCNTPE exhibits superior electrochemical performance toward determination of UA as compared to bare MWCNTPE. The voltammetric sensitivity of Chit-Ni²⁺ complex modified MWCNTPE toward UA oxidation was significantly improved, with a typical peak potential of 0.39 V (vs. SCE) in LiCl solution (0.1 M) at pH 2.4. Chit-Ni²⁺ complex modified MWCNTPE exhibited a linear current response (R² ~ 0.999) in the range of 0.05–144.3 µM UA. The limit of detection (LOD) limit for the Chit-Ni²⁺ complex modified MWCNTPE is found to be 0.01 µM. The Chit-Ni²⁺ complex modified MWCNTPE was highly selective for the electrochemical determination of UA even in the presence of other potential biomolecular interfering species.

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Given the economic, industrial, and environmental value of green dihydrogen (H₂), optimization of water electrolysis as a means of producing H₂ is essential. Binders are a crucial component of electrocatalysts, yet they remain largely underdeveloped, with a significant lack of standardization in the field. Therefore, targeted research into the development of alternative binder systems is essential for advancing performance and consistency. Binders essentially act as the key to regulating the electrode (support)–catalyst–electrolyte interfacial junctions and contribute to the overall reactivity of the electrocatalyst assembly. Therefore, alternative binders were explored with a focus on cost efficiency and environmental compatibility, striving to achieve desirable activity and stability. Herein, the alkaline hydrogen evolution reaction (HER) was investigated, and the sluggish water dissociation step was targeted. Controlled hydrophilic poly(vinyl alcohol)-based hydrogel binders were designed for this application. Three hydrogel binders were evaluated without incorporated electrocatalysts, namely PVA₁₄₅, PVA₁₄₅-blend-bPEI_1.8, and PVA₁₄₅-blend-PPy. Interestingly, the study revealed that the hydrophilicity of the binders exhibited an enhancing effect on the observed activity, resulting in improved performance compared to the commercial binder, Nafion™. Notably, the PVA₁₄₅ system stands out, with an overpotential of 224 mV at − 10 mA·cm⁻² (geometric) in 1.0 M KOH, compared to the 238 mV exhibited by Nafion™. Inclusion of Pt as active material in PVA₁₄₅ as binder exhibited a synergistic increase in performance, achieving a mass activity of 1.174 A.cm⁻².mg⁻¹_Pt in comparison to Nafion™’s 0.344 A.cm⁻².mg⁻¹_Pt, measured at − 150 mV vs RHE. Our research aimed to contribute to the development of cost-effective and efficient binder systems, stressing the necessity to challenge the dominance of the commercially available binders.

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Utilization of PVA-based polymers as alternative binders to enhance the sustainability and efficiency of the alkaline HER

The eco-friendly electrocatalytic nitrate reduction reaction (NO₃RR) at ambient condition is in high demand as a potential replacement for the Haber–Bosch process and for efficient wastewater treatment. The two multicomponent alloys electrocatalysts based on non-noble metals of Co75Si15Fe10 and Co75Si15Fe5Cr5 were synthesized. The samples were characterized and studied by the SEM, EDX, XRD, UV–vis spectroscopy, linear voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Under the conditions of chronoamperometry, ammonia was synthesized by NO₃RR and the values of Faradaic efficiency (FE) and yield rate of NH₃ were obtained. The highest FE 58.7% and the largest yield rate of NH₃ 4.3 μmol h⁻¹ cm⁻² at potential − 0.585 V (RHE) in a neutral electrolyte for the Co75Si15Fe10 electrocatalyst for NO₃RR. Unexpected for this work was the discovery of an inhibitory effect for an alloy containing a small amount of Cr. This work opens up interesting opportunities for further research of multicomponent alloys for NO₃RR.

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The multicomponent alloys electrocatalysts of Co75Si15Fe10 and Co75Si15Fe5Cr5 were synthesized. The eco-friendly electrocatalytic nitrate reduction reaction at ambient condition was used. Ammonia was synthesized by NO₃RR and the yield rate of NH₃ = 4.3 μmol h⁻¹ cm⁻². The Faradaic efficiency, FE = 58.7% at potential, E =  − 0.585 V (RHE).

In the present work, a straightforward approach was adopted to synthesize concentration-dependent multiwall carbon nanotubes with silver-doped titanium oxide (Ag-TiO₂) composites. The antibacterial activity was examined against Gram-positive and Gram-negative bacteria, increasing from 12.5 to 16.5 mm for S. aureus, 20.5 to 26 mm for C. jejuni, and 19.5 to 25.5 mm for V. cholerae, incorporating 5% and 10% MWCNTs with Ag-TiO₂, respectively. An Ag-TiO₂-10% MWCNTs-GCE system was developed for the simultaneous detection of ascorbic acid (AA) and paracetamol (PA). Under optimal conditions, the sensor demonstrates linearity for AA (0.5–300 µM) and PA (0.01–500 µM) (n = 3), respectively. The corresponding detection limits for AA and PA were 0.038 and 0.008 μM. This electrochemical sensor exhibits tremendous promise for a variety of medical applications, particularly in AA and PA monitoring, and offers a straightforward and extremely sensitive approach for detecting AA and PA in human serum samples and pharmaceutical samples.

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Electrochemical sensing is a promising approach for the selective and highly sensitive sensing of oxidized and reduced states of Nicotinamide adenine dinucleotide (NAD⁺/NADH). However, the limited selectivity, large overpotential requirements and the electrode fouling concerns associated with the till date reported NADH-specific electrodes continue to impede their potential utility for the design and development of fast, inexpensive and highly reliable point of care devices for electrochemical sensing of NAD⁺ and NADH. Herein we present a simple covalent functionalization approach for the design and development of Cytochrome-c (Cyt-c) functionalized Cu-BDC MOF (Cyt-c/Cu-BDC) as a novel Cu-Fe based bio-mimic for electrochemical sensing of NADH. Our detailed physical, chemical and electrochemical investigations carried out over the so designed Cyt-c/Cu-BDC composite establish it as an electronically conducting, electrochemically stable redox-active electrode material with an exceptional activity towards the selective and ultrasensitive electrochemical sensing of NADH. We demonstrate the practical utility of Cyt-c/Cu-BDC composite for accurate and sensitive electrochemical sensing of NADH in the pico-molar concentration range. The herein demonstrated extremely low LOD (10.4 pM), high sensitivity (12.02 ± 0.119 μA nM⁻¹ cm⁻²), good anti-interference ability and prolonged stability of the Cyt-c/Cu-BDC composite is far superior than the till date reported electrochemical sensors for NADH. These features qualify Cyt-c/Cu-BDC composite as a promising electrode material for the design of point-of-care NADH sensing devices for clinical diagnostics.

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Herein, we present a selective and sensitive electrochemical sensor for detecting formaldehyde in cosmetics, based on cobalt ferrite nanoparticles (CoFe₂O₄ NPs) modified on a glassy carbon electrode (GCE). The CoFe₂O₄ NPs were synthesized using a green biosynthetic route and characterized using UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The electrochemical performance of the GCE-CoFe₂O₄ NPs sensor was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and chronoamperometry (CA). Compared with the bare GCE, the modified electrode exhibited a significantly greater oxidation peak current for formaldehyde. The sensor demonstrated a linear dynamic range with a regression coefficient (R²) of 0.9193 and achieved limits of detection (LoD) and quantification (LoQ) of 0.056 mM and 0.184 mM, respectively, using DPV. Selectivity tests confirmed minimal interference from common substances such as ethanol and acetone at 10 mM concentrations. The sensor also exhibited excellent repeatability and reproducibility, with relative standard deviation (RSD) values of less than 5%. Practical applications of the sensor in detecting formaldehyde in nail polish remover yielded recovery rates ranging from 94 to 113%, demonstrating its reliability for real-world use. This study highlights the potential of green-synthesized CoFe₂O₄ NPs in the development of sustainable and efficient electrochemical sensors for monitoring harmful substances in consumer products.

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The development of electrocatalysts composed of abundant materials capable of supporting large-scale green hydrogen production has gained prominence due to the global energy transition. Electrodeposition is one of the most used methods for fabricating these materials, particularly Ni-Co-based alloys, due to their low cost, ease of processing, and controllability of operational parameters. This study conducted a systematic literature review to evaluate recent research on the effects of different ternary alloying elements in Ni-Co-based electrocatalysts and their impact on electrocatalytic properties for the hydrogen evolution reaction (HER). The methodology involved defining keywords and search strings, searching the Scopus Preview and ScienceDirect databases, and selecting primary research articles from 2019 to 2025. Inclusion and exclusion criteria narrowed the selection to ten articles. The analysis identified four key performance parameters used by authors to evaluate catalytic performance: overpotential (η), Tafel slope (b), charge transfer resistance (Rct), and electrochemically active surface area (ECSA). The addition of ternary elements to Ni-Co alloys primarily aims to enhance one or more of these factors. Graphical comparisons revealed emerging trends, such as metal–organic frameworks (MOFs) and alternative materials like cerium dioxide, leading to electrodes with performance comparable to platinum.

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Zileuton (ZLN) is a pharmaceutical agent utilized to manage inflammation-related disorders, including chronic obstructive pulmonary disease, upper respiratory tract conditions, and various dermatoses. It functions by inhibiting the synthesis of leukotrienes, which are mediators that contribute to edema, inflammation, mucus production, and bronchoconstriction. An overdose of ZLN can lead to significant adverse effects in patients; therefore, precise measurement of ZLN concentrations is essential. In the current study, copper-doped tungsten oxide (Cu-WO₃) nano-materials were employed to design carbon paste and prepare electrode materials for ZLN detection. The synthesized Cu-WO₃ nanomaterials were characterized using different analytical techniques. Cyclic and square wave voltammetry were performed to check the electrochemical behavior of ZLN on bare as well as modified electrodes. Results displayed a great enhancement in the peak current of ZLN, showing effect on sensitivity, specificity, and reliability for ZLN detection. Thus, the Cu-WO₃-modified electrode demonstrated much faster electron transport kinetics for the catalytic oxidation process than the unmodified carbon paste electrode. The studies on kinetics of oxidation under optimized conditions, the modified electrode exhibited a notable linear detection range of 5.0 × 10^–8 to 8.0 × 10^–6 M, with a limit of detection of 7.5 nM and a limit of quantification of 25.1 nM. For the electrochemical oxidation of ZLN, parameters such as the heterogeneous rate constant, electron transfer coefficient, and number of electrons involved were determined. The developed sensor was also employed to analyze ZLN in real sample matrices, yielding satisfactory results.

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In this study, an optically active iron(II)-terpyridine complex (Fe-pt) has been successfully prepared and characterized by different physicochemical methods. Its electrocatalytic performance for the oxygen evolution reaction (OER) was assessed by immobilizing Fe-pt onto Ni-foam electrodes. The system exhibited an overpotential of ~ 270 mV at 10 mA cm⁻², demonstrating excellent catalytic efficiency under alkaline conditions. Cyclic voltammetry (CV) and chronopotentiometry, confirmed its remarkable stability and OER activity. Structural and spectroscopic analyses revealed that the Ni-foam substrate enhances electron transport and provides robust support, further boosting the catalytic performance. Additionally a strong correlation could be observed between theoretical predictions and experimentally obtained structural and spectral changes during the catalytic process. This study highlights the potential of mononuclear Fe-pt complex as durable electrocatalyst for OER applications.

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Designing and developing efficient electrocatalytic materials for the oxygen evolution reaction (OER) remains a challenging yet highly compelling task. Transition metal-based catalysts are widely recognized as economical, stable, and efficient materials, as the Mⁿ⁺/M⁽ⁿ⁺¹⁾⁺ redox couple facilitates the formation of a charge-transfer orbital that enables electron transfer during the OER and the formation of –OOH species through surface reconstructions. However, it is fundamentally challenging to create available charge-transfer orbitals near the Fermi energy level. Herein, we demonstrate the crucial role of efficient electronic metal-support interactions in Ce_1−xCo_xO_2−δ, facilitating an effective redox couple between Co²⁺/Co³⁺ and Ce⁴⁺/Ce³⁺ to enhance OER kinetics. The evolution of lattice oxygen during OER and the Mⁿ⁺  → M⁽ⁿ⁺¹⁾⁺ oxidation process are efficiently facilitated by reducible CeO₂ support in the Ce_1−xCo_xO_2−δ solid-solution. The aliovalent-doped, phase-pure Ce_0.93Co_0.07O_2−δ exhibited exceptional performance, achieving a current density of 10 mA cm⁻² at an overpotential of 270 mV, with stable operation over 24 h. Mechanistic studies revealed that lattice substitution of the active sites facilitated stronger electronic metal-support interaction at the atomic level to improve catalytic performance.

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