Electrocatalysis最新文献

Electroanalytical performance of electrodeposited platinum nanoparticles (PtNPs), selenium nanoparticles (SeNPs), and tin oxide nanoparticles (SnO₂NPs) on the surface of bare fluorine-doped tin oxide (BFTO) (PtNPs-SeNPs-SnO₂NPs@BFTO) nanocomposite was used as an non-enzymatic electrochemical sensor towards detection of H₂O₂. The surface morphology and characterization of PtNPs-SeNPs-SnO₂NPs@BFTO was studied by field emission scanning electron microscopy (FESEM) and EDS mapping. The Morphology of PtNPs-SeNPs-SnO₂NPs@BFTO showed flower, spherical and irregular shapes by FESEM investigation. X-ray photoelectron spectroscopy was used to investigate the elemental composition of platinum, selenium, tin, oxygen, and fluorine on the PtNPs-SeNPs-SnO₂NPs@BFTO surface. The synthesized PtNPs-SeNPs-SnO₂NPs@BFTO electrochemical sensor was used for electro-catalytic detection of H₂O_2. The linear concentration range of the PtNPs-SeNPs-SnO₂NPs@BFTO was 0.01 to 54 mM, with a high sensitivity of 104.8 mA mM⁻¹ cm⁻² and a low detection limit of 0.01 mM. The interference study of PtNPs-SeNPs-SnO₂NPs@BFTO based sensors showed high selectivity towards H₂O₂ with interfering agents, including glucose (GU), ascorbic acid (AA), urea (UA), sucrose (SU), sodium chloride (SC), and sodium selenite (SS).

Study of the use of polymers with higher conductivity like polypyrrole, and polyaniline in the electrochemical insulin sensors can overcome the drawbacks arising from the ongoing use of non-conductive polymer membrane. Conductive polymer membranes maintain the positive properties of polymers, like improved stability, reproducibility, and even increase the current response of the prepared sensor toward insulin oxidation. Three different screen-printed electrodes modified with polyaniline, polypyrrole, or chitosan with electrochemically deposited nickel nanoparticles ensuring insulin oxidation were prepared. The electrode morphology was examined via SEM with EDX analysis. Also, the electroactive surface area and stability were determined by voltammetric methods. Based on the results, the SPCEs modified by polypyrrole and nickel nanoparticles were determined as the most appropriate for the insulin determination. The NiNPs-PPy-SPCE exhibited a linear range (500 nM–5 µM), a low-down limit of detection (38 nM), high sensitivity (3.98 µA/µM), and excellent result from insulin determination in real samples (human blood serum). The results confirmed the high potential of developed sensor for future research focused on detection of insulin via electrochemistry methods in clinical samples.

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This paper describes the development of a carbon paste electrode based on the butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([bmim] NTF2) ionic liquid and its modification with functionalized multiwalled carbon nanotubes (f-MWCNTs) /graphene (GR) nanocomposite film. The f-MWCNTs-GR modified carbon ionic liquid paste electrode (CILPE) was utilized for electrochemical determination of tyramine using the square wave voltammetry technique. The prepared electrochemical sensor exhibited an excellent electrocatalytic behavior for oxidation of tyramine molecules in solutions compared to the carbon paste electrode. This behavior can be assigned to the synergistic effect of carbon nanotubes, graphen and ionic liquid. The oxidation peak currents of tyramine were linear in the concentration range of 1–1000 μM with a detection limit of 0.5 μM. The obtained experimental results showed that the f-MWCNTs-GR/CILPE has a good selectivity toward tyramine molecules in the presence of interfering specious and it can be used confidently for measurement the concentration of tyramine in food and biological samples.

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Chlorpheniramine (CPM) is a widely used antihistamine drug that may be desirable to quantify in a variety of samples. We developed a CPM electrochemical sensor based on a composite of reduced graphene oxide (rGO) and silver nanoparticles (AgNPs) coated on a glassy carbon electrode (GCE). Sodium dodecyl sulfate (SDS) was used as a surfactant to prevent the aggregation of AgNPs. rGO and AgNPs were co-electrodeposited by cyclic voltammetry, varying the potential from -1.5 to 1.5 V vs. Ag/AgCl 3 M KCl. The electrochemical properties of the modified electrode were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The rGO/AgNPs/GCE showed excellent electrocatalytic activity for the oxidation of CPM. The anodic peak potential, measured using CV, was 0.78 V vs. Ag/AgCl in a carbonate-bicarbonate buffer of pH 10. The modified electrode exhibited a linear response for CPM concentrations between 10 and 300 μM, with a limit of detection of 4.2 μM. Several potentially interfering species, including ionic and organic compounds, did not have any significant effect on the CPM determination. This work thus describes a versatile sensor that could be applied to measure CPM in real samples.

In the development of ultrasensitive and selective sensors for heavy metal ions, the fabrication of titania-modified carbon paste electrodes with electrochemical sensing capabilities has received considerable attention. In this study, we investigated the facile preparation of the titania-modified carbon paste electrode and the determination of trace amounts of hazardous Hg(II), Cu(II), and Pb(II) ions by applying the square wave anodic stripping voltammetry method. The titania nanoparticles were characterized using various techniques such as size analyzer, XRD, and FTIR to determine their chemical properties. The experimental findings demonstrated that the titania nanoparticles were uniformly distributed in the graphite used to construct the modified electrode and had an average particle size of 85 nm in crystalline anatase form. Compared with the measurement results, the prepared sensor exhibited excellent sensing performance against Hg(II), Cu(II), and Pb(II) ions with a low detection limit of 15.26, 0.56, and 1.65 nM, respectively. In ternary solutions, their simultaneous determinations showed that the electrode is more sensitive to Hg(II) and Pb(II) ions, with detection limits of 8.32 and 0.25 nM, respectively. Consequently, the experimental results showed that the titania-modified carbon paste electrode is a promising sensor for the determination of hazardous Hg(II), Cu(II) and Pb(II) ions in sensor applications.

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Electrochemical (EC) water splitting is a promising approach for the generation of renewable hydrogen (H₂) fuels and oxygen (O₂) evolution. Composite structured molybdenum disulphide (MoS₂)/vanadium pentoxide (V₂O₅) with low overpotential is a promising electrocatalyst for anodic and cathodic material for an alternative energy source. We fabricated a flower shape MoS₂/V₂O₅ composite via a hydrothermal approach where V₂O₅ grew on the surface of the MoS₂ petals. The unique flower-type composite structure alleviates the surface expansion of electrode material. The electrochemical studies show that the composite possesses good stability with low overpotential and smaller Tafel slope compared to its constituents. It has been found that the MoS₂/V₂O₅ composite exhibits a stable rate performance under the current density of 10 mA cm⁻² which indicates that the MoS₂/V₂O₅ composite might be a good candidate for both oxygen and hydrogen evolution reactions.

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Metal clusters often exhibit superior chemical, electronic, and geometrical properties and can show exciting catalytic performance. The catalytic behaviour of the clusters is strongly affected by their size and composition, offering unique opportunities to fine-tune such materials for a specific application. In this study, atomically precise [Au₆(dppp)₄](NO₃)₂, [Au₉(PPh₃)₈](NO₃)₃, [Au₁₃(dppe)₅Cl₂]Cl₃ and Au₁₀₁(PPPh₃)₂₁Cl₅ clusters were synthesised, characterised and their activity for electrocatalytic CO₂ reduction is compared. These Au clusters were deposited onto carbon paper to serve as the cathode for the electrochemical reduction of CO₂. The experimental studies suggest that the clusters remain intact upon deposition on the carbon paper but undergo agglomeration during CO₂ electrolysis. The cluster-based catalysts demonstrated high selectivity (75%—90%) for CO production over hydrogen evolution reaction. Upon calcination, the activity of the cluster-based electrodes decreases, which can be attributed to the agglomeration of small clusters into larger bulk-like nanoparticles, as suggested by XPS, XAS and SEM.

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A series of phosphine-protected gold clusters supported on carbon paper were studied as CO₂RR electrocatalysts. The CO₂RR activity was dependent on their size and ligand density. Thermal annealing of the catalysts invariably lowered CO selectivity due to agglomeration of the clusters into larger nanoparticles.

Bis(iminidiacetato)cobaltate(III) complex has been evaluated for electrocatalytic proton reduction. The process follows a rare pathway of protonation of ligand upon addition of a weak acid in DMF/water (9:1 v/v) medium. Thus, the complex becomes electroactive only in the presence of acid. In the presence of weak acid, a new reduction peak corresponding to Co^I/Co⁰ reduction is observed. The electrocatalytic activity towards proton reduction reaction is exhibited by this peak. An electrochemical-chemical-electrochemical (ECE) route initiated by proton relay on ligand site has been established for the electrocatalytic process. The catalytic activity of the complex in DMF/water medium was evaluated by controlled potential electrolysis, turnover number (TON), and turnover frequency (TOF).

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The effect of Te doping of the TiO₂/Ti nanotube arrays (NTAs) on the photoelectrochemical chemical oxygen demand (COD) detection has been investigated. It is found that the Te doping has enhanced the photoelectrocatalytic properties of the TiO₂/Ti NTAs electrode. This indicated by the linearity, accuracy, and repeatability of measurement of the test compounds chemicals. The Te-TiO₂/Ti NTAs shows an excellent linearity to all test compounds up to 10 μM of concentration. It is only up to 5 μM in pristine TiO₂/Ti NTAs system. In term of accuracy, the Te-TiO₂/Ti NTAs electrode can provide the measurement accuracy of up to 100% fit to the theoretical value for all test compound chemical. It is only less than 80% for TiO₂/Ti NTAs electrode. Meanwhile, the repeatability of measurement for the electrode, the Te-TiO₂/Ti NTAs exhibits 1.8% RSD value, which is lower than the pristine TiO₂/Ti NTAs, i.e., 2%. The enhancement of the photoelectrocatalytic properties of the TiO₂ by Te doping is due to the lowering of electron and hole recombination during the photoactivation, promoting massive surface reaction with organic compounds and improving the sensing sensitivity. The Te-TiO₂/Ti NTAs should find the extensive application of PECOD detection of organic contamination in the environment.