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Electrocatalysis
Journal Prestige (SJR): 0.994  Citation Impact (citeScore): 3 Number of Followers: 4  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1868-2529 - ISSN (Online) 1868-5994 Published by Springer-Verlag  [2468 journals]
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- Electroanalytical Performance of Non-Enzymatical Electrochemical Sensor
Based on PtNPs-SeNPs-SnO2NPs@BFTO Nanocomposites for the Detection of
Hydrogen Peroxide-
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Abstract: 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 H2O2. 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).
PubDate: 2023-05-25
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- Polymer-based Electrochemical Sensor: Fast, Accurate, and Simple Insulin
Diagnostics Tool-
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Abstract: 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. Graphical
PubDate: 2023-05-10
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- Electrochemical Determination of Tyramine Using a Carbon Ionic Liquid
Paste Electrode Modified with f-MWCNTs/Graphene Nanocomposite Film-
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Abstract: 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. Graphical
PubDate: 2023-05-05
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- Co-deposition of Graphene Oxide and Silver Nanoparticles for the
Voltammetric Sensing of Chlorpheniramine-
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Abstract: 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.
PubDate: 2023-05-03
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- Individual and Simultaneous Determination of Heavy Metal Ions Using Carbon
Paste Electrode Modified with Titania Nanoparticles-
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Abstract: 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. Graphical
PubDate: 2023-05-01
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- Fast and Efficient Dye Elimination Over One-Pot Synthesized and Si-Rich
[Fe]-ZSM-5 Catalyst in Electro-Fenton Process-
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Abstract: Synthetic organic dyes contaminate the aquatic environment. A fast and efficient preparation of catalysts plays a vital role in wastewater treatment to reduce costs and increase its market. In this study, we prepared different Si-rich ZSM-5 catalysts (Si/Al = 200) through the one-pot synthesis and impregnation technique that include Fe species. The catalysts were applied in heterogeneous electro-Fenton (HEF) to remove methylene blue (MB), an organic dye which is a model compound for water contaminants. The parent and modified catalysts were characterized by XRD, FT-IR, FE-SEM, NH3-TPD, and N2 adsorption–desorption methods. The results showed the well crystalline framework (89%), high surface area (359 m2 g−1), mesopore structure (0.05 cm3 g−1), and uniform distribution of the Fe species. The optimum operating conditions for the [Fe]-ZSM-5 catalyst were pH = 4, applied current of 100 mA, and catalyst concentration of 0.1 g L−1, which resulted in the highest MB removal (98%) in 15 min through the HEF process. The results confirm the applicability of the one-pot synthesis of the [Fe]-ZSM-5 catalyst.
PubDate: 2023-05-01
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- Crystal Size Dependence of the Photo-Electrochemical Water Oxidation on
Nanoparticulate CaTiO3-
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Abstract: Nanocrystalline CaTiO3 materials with controlled particle size were prepared using spray-freezing/freeze-drying approach utilizing gelatine as a structure-directing agent. The resulting materials show characteristic particle size between 19 and 60 nm. The shape of the nanocrystals changes from cube-like single crystal containing particles into less regular isometric particles. Prepared materials as identified by X-ray diffraction analysis are formed by orthorhombic perovskite with small admixture of cubic phase. The ratio of both perovskite phases is independent of the particle size or prevailing crystal shape. All prepared materials show n-semiconducting character with band gap of ca 3.6 eV. They also show photo-electrochemical activity in water oxidation in acid media if a bias greater than 400 mV with respect to the flat band potential is applied. The specific photo-electrochemical activity decreases with increasing specific surface area. This behavior is attributed to increased probability of the electron transfer at the illuminated CaTiO3 surface facilitated by the surface states. The CaTiO3 materials also generate significant amount of ozone upon illumination in oxygen saturated solutions. The tendency to form ozone increases with increasing particle size suggesting that the ozone formation is hindered on materials with large number of low dimensionality states (crystal edges and vertices). Graphical
PubDate: 2023-05-01
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- Simultaneous Detection of Dopamine and Paracetamol on Electroreduced
Graphene Oxide–Cobalt Phthalocyanine Polymer Nanocomposite Electrode-
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Abstract: The fabrication of sensitive, fast, cost-effective and eco-friendly electrochemical sensors is essential for monitoring analytes of biomedical, environmental and pharmaceutical interests. Herein, we report the simultaneous electroreduction and deposition of graphene oxide (GO) to form electrochemically reduced graphene oxide (ERGO) onto a glassy carbon electrode (GCE) represented as GCE-ERGO. Onto the GCE-ERGO, cobalt (II) tetra-amino phthalocyanine was electropolymerized to form a stable GCE-ERGO/polyCoTAPc. The sensing surface, GCE-ERGO/polyCoTAPc, was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques to ascertain its electron transfer and conducting properties. The modifier surface functional groups and composition were confirmed using infrared spectroscopy and energy-dispersive X-ray spectroscopy. The prepared sensing electrode displayed enhanced electrocatalytic activity towards ferri/ferrocyanide {[Fe(CN)6]3−/4−} as a redox probe. GCE-ERGO/polyCoTAPc was further used for ultrasensitive simultaneous detection and determination of dopamine (DA) and paracetamol (PA). The electrocatalytic peak currents for DA and PA were greatly enhanced with an oxidation potential difference of 264 mV, wide enough for simultaneous determination. Using differential pulse voltammetry (DPV), the electrocatalytic oxidation peak currents of DA and PA at GCE-ERGO/polyCoTAPc showed linear dependence with the changes in concentrations up to 100 µM for DA and up to 90 µM for PA. The limits of detection (LOD) values were 0.095 µM and 0.10 µM using a signal-to-noise (S/N) ratio of 3 for DA and PA, respectively. The GCE-ERGO/polyCoTAPc displayed excellent sensitivity of 8.39 µA µM−1 cm−2 for DA and 1.32 µA µM−1 cm−2 for PA. The fabricated ultrasensitive electrochemical sensor was successfully used for the determination of DA and PA in synthetic urine samples with excellent percentage recoveries.
PubDate: 2023-05-01
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- CuCo-MOF/MoS2 as a High-Performance Electrocatalyst for Oxygen Evolution
Reaction-
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Abstract: Metal–organic frame materials (MOFs) create ordered spatial structures through organic bridges and metal ion centers. This microstructure can effectively disperse the active centers. In this work, CuCo-MOF was firstly prepared by hydrothermal method and then physically mixed with MoS2. The prepared materials were applied to study the catalytic performance for oxygen evolution reaction (OER). The results show that the overpotential and Tafel slope of CuCo-MOF/MoS2 are 336 mV and 75 mV dec−1. The addition of MoS2 can effectively reduce the stacking of MOFs and increase the effective contact area with the reactants and promote charge/mass transport as well as enhance the catalytic activity. In addition, MoS2 has strong viscosity, and when it is mixed with MOF, the stability of the composite can be improved. The good OER performance of CuCo-MOF/MoS2 provides a reference for the exploration of a novel OER catalyst.
PubDate: 2023-05-01
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- Determination of o-Aminophenol by Novel Co(II) Phthalocyanine with
Appliance of Composite MWCNTs-
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Abstract: A novel peripherally tetra naphthol substituted Co(II) phthalocyanine (NCoPc) was synthesized by the reaction of naphthol linked phthalonitrile, and cobalt chloride, in the presence of catalytic amount of DMF, DBU, and K2CO3. The NCoPc and its composite with MWCNTs were characterized by FTIR, NMR, UV–Vis, XRD, TGA, and mass spectroscopic techniques. The NCoPc and NCoPc-MWCNTs-coated glassy carbon electrodes (GCEs) were used to electrochemically detect and quantify ortho amino phenol (oAP) oAP in aqueous solutions. Cyclic voltammetric data established a linear response between the oAP oxidation current (ipa) and its molar concentration (10–190 μM). The limit of detection (LoD) of the two modified electrodes was comparable (1.5 μM and 25 nM, respectively). The NCoPc and NCoPc-MWCNTs-GCEs (in the concentration range of 10–160 μM) were both low and comparable. The LoD values for oAP at the NCoPc-GCE and NCoPc-MWCNTs by DPV were 1.2 µM and 42 nM and CA were 10 nM and 6.5 nM, respectively. They are exhibited good electrocatalytic activity towards the oxidation of oAP, and this was aided by the improved conductivity of the composite modifiers. Graphical
PubDate: 2023-05-01
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- Gamma Radiolysis-Synthesized Carbon Nanotube–Supported Palladium as
Electrocatalyst for Oxygen Reduction Reaction-
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Abstract: Electrocatalysts are used to promote efficient energy conversion in fuel cell, especially for the sluggish oxygen reduction reaction (ORR) at the cathode that inhibits the performance of the device. In this work, we demonstrate the use of a facile gamma radiolysis technique to synthesize carbon nanotube-supported palladium (Pd) metal particles as electrocatalysts for the ORR application. The Pd precursor concentration used in the preparation process was found to contribute greater effects on the Pd content and Pd crystallite size of the synthesized product compared to the gamma irradiation dose. The results showed that gamma radiolysis could successfully reduce Pd ions from its precursor solution as evidenced from field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) characterization. The optimal ORR electrocatalyst was prepared using 0.01-M Pd precursor and a gamma radiation dose of 50 kGy. It displays a high half-wave potential (E1/2) of 0.84 V (vs. RHE) and superior electron transfer number (n) of 3.96, as well as a low peroxide yield of 1.8%. This impressive ORR electrocatalytic performance was also attributed to the synergistic effect of Pd metal particles with CNT. The findings showed that Pd/CNT is a promising electrocatalyst for ORR application and that gamma radiolysis provides a facile and eco-friendly approach in synthesizing electrocatalysts.
PubDate: 2023-05-01
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- Investigation of Charge–Discharging Behavior of Metal Oxide–Based
Anode Electrocatalysts for Alkaline Water Electrolysis to Suppress
Degradation due to Reverse Current-
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Abstract: In the bipolar-type alkaline water electrolysis powered by renewable energy, electrocatalysts are degraded by repeated potential change associated with the generation of reverse current. If an electrode has large discharge capacity, the opposite electrode on the same bipolar plate is degraded by the reverse current. In this study, discharge capacity of various transition metal-based electrocatalysts was investigated to clarify the determining factors of electrocatalysts on the reverse current and durability. The discharge capacities from 1.5 to 0.5 V vs. RHE (Qdc,0.5) of electrocatalysts are proportional to the surface area in most cases. The proportionality coefficient, corresponding to the specific capacity, is 1.0 C·m–2 for Co3O4 and 2.3 C·m–2 for manganese-based electrocatalysts. The substitution of Co3+ in Co3O4 with Ni3+ increased Qdc,0.5. The upper limit of theoretical specific capacity for Co3O4 is estimated to be 1.699 C·m–2, meaning the former and latter cases correspond to 2- and 1-electron reactions, respectively, per a cation at the surface. The discharge capacities of the elctrocatalysts increased because of the dissolution and recrystallization of nickel and/or cobalt into metal hydroxides. The increase in the capacities of Co3O4 and NiCo2O4 during ten charge–discharge cycles was below 2–9% and 0.5–38%, respectively. Therefore, if a cathode electrocatalyst with relatively low redox durability is used on the one side of a bipolar plate, it is necessary to control optimum discharge capacity of the anode by changing surface area and constituent metal cations to minimize the generation of reverse current. Graphical
PubDate: 2023-05-01
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- Development of Unsupported Ru and Ni Based Oxides with Enhanced
Performance for the Oxygen Evolution Reaction in Acidic Media-
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Abstract: The high cost of catalyst materials suitable for the oxygen evolution reaction (OER) in polymer electrolyte membrane water electrolyzers (PEMWE) is still a major hurdle that needs overcoming before commercial PEMWE can have a meaningful impact as a technology in the hydrogen economy. Metal oxides based on precious metals are currently still the most reliable and most used materials as catalysts in PEMWE; however, alternative or modified materials are desirable to help reduce the cost associated with the catalyst component. In this study, we report on binary metal oxide catalysts based on Ru and Ni. Ni-based electrodes are typically used in alkaline water electrolyzers due to their high performance, robustness and low cost; however, Ni and NiO electrodes do not show promising performance in acidic environments due to corrosion. By combining NiO with acid stable RuO2, we have demonstrated that the performance of the RuO2 catalyst can be improved and due to the lower cost of Ni, the cost of the catalyst can ultimately be reduced. The Ni addition was limited to 10 mol% to achieve improved OER performance followed by noticeable performance degradation as the Ni composition was increased. The metal oxide catalysts were synthesized via a modified Adams fusion method that produced nano-sized catalysts with superior performance compared to a state-of-art commercial RuO2 catalyst. Physical characterizations were performed via high-resolution transmission electron microscopy, X-ray diffraction, energy dispersive X-ray, and Brunauer Emmett Teller analyses. OER performances were evaluated via cyclic voltammetry, linear sweep voltammetry, chronopotentiometry, and chronoamperometry analyses. Graphical
PubDate: 2023-05-01
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- Optimization of Ni-Mo-Coated Stainless Steel as a High-Performance Cathode
in Alkaline Water Electrolysis-
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Abstract: Considering the widespread use of alkaline water electrolysis (AWE) in the chemical industry and the growing need to design and manufacture low-cost and efficient electrodes, the optimization of a Ni-Mo-coated stainless steel substrate is investigated in the present work to use this substrate as a cathode of an alkaline water electrolyzer. The crystallographic structure, surface morphology, and composition of the optimized coating are characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and surface elemental mapping. The electrocatalytic activity for the hydrogen evolution reaction (HER) is evaluated by making electrochemical measurements. In addition, the optimization of the electrodeposition bath is investigated to promote the HER activity. The results show that nickel-molybdenum (1:2) alloy exhibits a higher HER activity, and a current density of 180 mA cm−2 is achieved at −1.7 V vs. Ag/AgCl using this coating. Also, the polarization curves of the electrolysis cell demonstrate that using the optimized cathode, the cell operates at 1.9 V at a current density of 1.5 A.cm−2 and the operating temperature of 60 °C, which is suitable for use in large-scale industrial AWE units. Graphical
PubDate: 2023-05-01
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- Sea Urchin–Like CoS2@WS2/NF Bifunctional Catalyst for Efficient
Overall Water Splitting-
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Abstract: Metal sulfides have been shown to exhibit better electrical conductivity, mechanical and thermal stability, and higher electrochemical activity than their corresponding metal oxide counterparts. The one-dimensional nanoclusters and three-dimensional microspheres were assembled together by a well-designed synthetic strategy to finally form a sea urchin-like CoS2@WS2/NF composite electrode material. The stable chemical properties and firm physical structure remain stable before and after the catalytic reaction, and the unique structure, sea urchin-like morphology, is conducive to mass transfer and gas release during the reaction. In this nanocomposite, one-dimensional nanoclusters provide efficient electron transfer, while three-dimensional nanospheres provide strong and reliable mechanical support. When CoS2@WS2/NF was used as a bifunctional electrocatalyst at a current density of 10 mA cm−2 in 1.0 M KOH aqueous solution, it exhibited overpotentials as low as 127 mV and 415 mV to drive hydrogen evolution reaction (HER) and HER, respectively. Oxygen evolution reaction (OER) is responsive while having high durability. When evaluated as a two-electrode system, it delivers a small value of 1.66 V up to 10 mA cm−2, further demonstrating the superiority of the bifunctional water release function.
PubDate: 2023-05-01
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- Electrochemical Detection of Nevirapine Using Banana Peel Extract
Functionalised Nickel Selenide Quantum Dots-
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Abstract: Nickel selenide quantum dots (NiSe2QDs) were synthesised using the aqueous colloidal method with banana peel extract (BPE) utilised as a capping agent. A gold electrode modified with the BPE-capped NiSe2QDs was used for the determination of nevirapine. Characterisation of the BPE-NiSe2QDs was conducted using high-resolution scanning electron microscopy (HRSEM), high-resolution transmission microscopy (HRTEM) and small-angle X-ray scattering (SAXS) which all revealed the spherical morphology of the QDs and their small sizes (˂ 10 nm). Optical properties of the BPE-NiSe2QDs studied by ultraviolet–visible spectroscopy (UV–Vis) revealed an absorbance band at 329 nm corresponding to an energy bandgap value of 2.99 eV. The electrochemical experiments were performed using differential pulse voltammetry. The Au/BPE-NiSe2QDs/Nafion-based electrochemical sensor showed a distinctive anodic response towards nevirapine at 0.76 V. The results obtained showed that the oxidation peak current increased linearly as the nevirapine concentrations increased in the range 0–1.21 pM (0–0.322 ng/L) with a low limit of detection (LOD) of 0.024 pM (0.0064 ng/L) and sensitivity of 5.52 µA/pM. These exceptional properties are comparable to or even better than already reported sensors for complex matrices. The electrochemical sensor demonstrated high repeatability and stability. The proposed sensor was successfully used for nevirapine detection in spiked wastewater samples with satisfactory results.
PubDate: 2023-05-01
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- Fabrication of a Novel Photoelectrochemical Aptasensor Using Gold
Nanoparticle-Sensitized TiO2 Film for Quantitative Determination of
Diazinon in Solutions-
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Abstract: This paper reports the development of a simple and new photoelectrochemical (PEC) aptamer-based sensor for ultrasensitive determination of the concentration of diazinon (DZN) using the surface plasmon resonance effect (SPR) of gold nanoparticles (AuNPs) deposited on a titanium dioxide (TiO2) film. A thin layer of flourin tin-oxide (FTO) was covered on the surface of glass plates during the spray pyrolysis process, and the resulting FTO plates were modified layer by layer with TiO2 film and AuNPs as the photoactive nanomaterials. The AuNPs were utilized to increase the absorption rate of visible light through the formation of hot electrons. The prepared AuNPs/TiO2 nanocomposite revealed a higher photoelectro catalytic activity compared to the pure TiO2. In order to improve the selectivity of the proposed PEC sensor, the thiolated aptamer was conjugated to the AuNPs/TiO2 nanocomposite through S–Au bonds. Upon exposition of the fabricated PEC apatasensor to DZN molecules, the formation of the aptamer-DZN complex restricted the electron transfer at the surface of the PEC sensor; therefore, the photocurrent signal decreased. The simultaneous usage of the PEC technique and aptamer led to the improvement of the analytical performance of the proposed sensor in terms of sensitivity, selectivity, reproducibility, and stability for the quantitative determination of diazinon with a wide linear range of 0.2 to 1000 nM and a low detection limit of 0.04 nM. In addition, the prepared PEC aptasensor was used for the determination of diazinon in water and biological samples, and satisfactory results were obtained which confirms the practical application of the proposed PEC aptasensor.
PubDate: 2023-05-01
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- Facile Synthesis of Silver-Doped Copper Selenide Composite for Enhanced
Electrochemical Detection of Ecological Toxic Nitrobenzene-
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Abstract: Nitrobenzene(NB) is frequently utilized in the production of numerous products and aromatic compounds. Highly toxic nitrobenzene (NB) and its derivatives mix with water resources and cause various serious effects on human health and the environmental ecosystem. It is vital to accurately detect highly dangerous aromatic nitro compounds in the water medium for the sake of safeguarding both human health and environmental safety. Hence, the detection of NB and its derivatives is one focus of electrochemical sensor development. In this work, a sensitive NB sensor has been developed using Ag-CuSe composite. The prepared Ag-CuSe composite modified with a glassy carbon electrode (GCE) has been used for the detection of NB and real sample analysis. In addition, the morphology, crystallinity, and functionality of the Ag-CuSe composite have been determined by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and elemental mapping. The electrocatalytic reduction mechanism and kinetic parameters of the NB at the GCE/Ag-CuSe electrode have been evaluated by cyclic voltammetry, differential pulse voltammetry, and amperometry in 0.05 M phosphate buffer solution (pH 7.0). The GCE/Ag-CuSe-modified electrode exhibited excellent electrochemical activity toward the detection of NB with a low limit of detection (S/N = 3) of 0.01 µM, good sensitivity of 3.64 µA µM−1 cm−2, and a linear response range of 0.1 to 400 µM. Moreover, the Ag-CuSe-modified electrode has excellent selectivity, repeatability, reproducibility, and anti-interference ability, as well as good stability. The prepared GCE/Ag-CuSe electrode has been successfully applied to the removal of pollutants from various real water samples with good recovery results. The proposed GCE/Ag-CuSe electrode has been used for the trace-level detection of nitrobenzene in environmental samples.
PubDate: 2023-05-01
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- Electrochemical Deposited Amorphous Bimetallic Nickle-Iron (Oxy)hydroxides
Electrocatalysts for Highly Efficient Oxygen Evolution Reaction-
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Abstract: The low-cost and high-performance electrocatalysts, especially metal (oxy)hydroxides, for the oxygen evolution reaction (OER) have attracted considerable attention due to their promising OER activity. Amorphous electrocatalysts are often superior to their crystalline counterparts due to their more actives and structural flexibility. However, using traditional preparation techniques still presents a significant barrier. Herein, the amorphous NiFe (oxy)hydroxides on nickel foam (NF) with large surface area and small charge transfer resistance were fabricated by electrodeposition technique. The as-fabricated NiFe (oxy)hydroxides (Ni:Fe = 1:3) exhibited remarkable electrocatalytic activity and stability for OER with a low overpotential of 245 mV at a current density of 100 mA cm–2, a small Tafel slope of 76.9 mV dec−1, which was superior to that of noble metal electrocatalysts (RuO2) and most NiFe-based electrocatalysts. This work provides a facile and effective way to synthesis metal (oxy)hydroxide catalysts towards high-efficiency water splitting.
PubDate: 2023-05-01
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- Electrocatalytic Performance of Nickel Hydroxide-Decorated Microporous
Nanozeolite Beta-Modified Carbon Paste Electrode for Formaldehyde
Oxidation-
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Abstract: In this paper, aluminosilicate nanozeolite beta has been prepared and described using X-ray diffraction (XRD), nitrogen sorption isotherm, Fourier transform infrared (FT-IR), transmission electron micrograph (TEM), and field emission scanning electronic microscopy (FESEM) techniques; TEM image demonstrated semispherical particles with dimensions under 50 nm. The BET surface area, total pore volume, and pore diameter of it were attained to be 321 m2 g−1, 0.053 cm3 g−1, and 1.22 nm, respectively. The modified carbon paste electrode by aluminosilicate nanozeolite beta and nickel hydroxide (Ni(OH)2-Beta/CPE) was applied for formaldehyde (HCHO) electrocatalytic oxidation. The obtained results specify that Ni(OH)2-Beta/CPE demonstrates worthy electrocatalytic activity for oxidation of HCHO due to mesoporous construction and the great surface area of nanozeolite. The electron-transfer coefficient, catalytic rate constant, and diffusion coefficient are found to be 0.69, 2.08 × 106 cm3 mol−1 s−1, and 4.4 × 10−7 cm2 s−1, respectively. The Ni(OH)2-Beta/CPE exhibited low background current, simplicity of surface renewal, good reproducibility, and stability and also displayed high stability up to 300 cycles and 3000 s without an important loss in the current density. This modified electrode has better poisoning tolerance capability than bare CPE for HCHO electrocatalytic oxidation and is a higher device for the long term accomplishment.
PubDate: 2023-05-01
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