We prepared the novel materials of Y-doped SnO2-CdO nanocomposite, Y-SnO2 and CdO nanoparticles by a facile chemical technique. Structural, crystallite size and lattice parameters are investigated by ...XRD spectrometer. The morphologies show highly aggregated due to tiny particles of Y3+, Sn4+ and Cd2+ were present in nanocomposite were analyzed by HR-TEM. The presence of a functional group of elements was identified by FT – IR spectrometer. The X-ray photoelectron spectroscopy (XPS) is used to analyze the ionization state of elements, composition and purity of the nanocomposite. Optical properties such as lower absorption edge, widened band gap and particle size were studied by UV – visible spectrometer and Photo luminescence (PL) was used to determine the violet emission of nanocomposite. At room temperature, ferromagnetism was obtained in the nanocomposite was studied by VSM. From Cyclic-Voltammetry (CV), the nanocomposite has behave as pseudocapacitance that occurs in the potential range between – 0.7 V to 0.5 V. Electrochemical impedance spectroscopy (EIS) was investigated for impedance, dielectric, electric modules and a.c conductivity of nanocomposite. Because of its optical, magnetic, and electrochemical characteristics, the Y-SnO2-CdO nanocomposite is therefore ideally suited for a variety of possible multifunctional applications.
•A simple chemical method was used to prepare the Y-doped SnO2–CdO for the first time.•They have a mixed rutile tetragonal - cubic structure and a quasi-spherical shape.•Enhanced photocatalytic activities and ferromagnetic behaviour were obtained.•At room temperature, the constant pseudo capacitance occurs for several scan rates.•They have large impedance, very low dielectric loss and non-Debye relaxation.
The present work, novel growth of ternary CuO-Fe3O4/g-C3N4 nanocomposites (NCs) with three different ratio (CuO-Fe3O4:g-C3N4 = 90:10; 75:25 and 50:50), binary CuO-Fe3O4 nanocomposite (NC) and its ...pristine g-C3N4, CuO and Fe3O4 was synthesized and characterized by XRD, SEM with EDX, TEM, Raman, XPS, UV-DRS and PL. The XRD pattern exhibited the diffraction peaks of g-C3N4 (hexagonal) and CuO (monoclinic) and Fe3O4 (FCC) and the CuO-Fe3O4 mixing of monoclinic and cubic phases along with CuO (−111) direction. The TEM analysis shows the dispersion of CuO-Fe3O4 on g-C3N4 sheets in the CuO-Fe3O4/g-C3N4 (50:50) NC. From the XPS spectra, the oxidation states of Cu2p, Fe2p, O1s, C1s, and N1s, as well as their orbital bonding, are analyzed. The bandgap was calculated by photon energy vs ILD and (F(R∞)hv)2 by using UV-DRS spectrum. The catalyst, CuO-Fe3O4/g-C3N4 (50:50)@NF had a low overpotential of 69 mV at the current density of 10 mA cm2, close to the value of 20 % Pt (45 mV). A chronoamperometry test demonstrated that CuO-Fe3O4/g-C3N4 (50:50)@NF works efficiently for more than 30 h at a high current density of 15 mA cm−2 indicating the strong stability of CuO-Fe3O4/g-C3N4 (50:50)@NF. The maximum photocatalytic degradation efficiency against Rhodamine-B was found to be 99.51 % and crystal violet degradation efficiency is 98.02 % by using CuO-Fe3O4/g-C3N4 (50:50).
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A 51-year-old man with alcoholic liver cirrhosis was hospitalized for treatment of rectal varices. 3D-CT revealed that the rectal varices’ inflow vessel was the superior rectal vein─branching from a ...mesenteric vein─and outflow vessels were the middle and inferior rectal vein draining into the internal iliac vein. The diameter of the inferior mesenteric vein was thinner than that of the left gastric vein. Therefore, it was speculated that the variceal blood flow rate would be low, and endoscopic injection sclerotherapy (EIS) was selected as the treatment method. EIS was performed using 5% ethanolamine oleate with iopamidol. Endoscopic varicealography during injection sclerotherapy (EVIS) clearly showed the rectal varices, superior rectal vein, and inferior mesenteric vein. After treatment, complete embolization of the rectal varices and inflow vessels was confirmed by contrast enhanced CT, and endoscopy revealed disappearance of the rectal varices. This case of rectal varices was successfully treated using EIS.
Electrochemical impedance spectroscopy (EIS) is a widely used experimental technique for characterising materials and electrode reactions by observing their frequency-dependent impedance. Classical ...EIS measurements require the electrochemical process to behave as a linear time-invariant system. However, electrochemical processes do not naturally satisfy this assumption: the relation between voltage and current is inherently nonlinear and evolves over time. Examples include the corrosion of metal substrates and the cycling of Li-ion batteries. As such, classical EIS only offers models linearised at specific operating points. During the last decade, solutions were developed for estimating nonlinear and time-varying impedances, contributing to more general models. In this paper, we review the concept of impedance beyond linearity and stationarity, and detail different methods to estimate this from measured current and voltage data, with emphasis on frequency domain approaches using multisine excitation. In addition to a mathematical discussion, we measure and provide examples demonstrating impedance estimation for a Li-ion battery, beyond linearity and stationarity, both while resting and while charging.
•Trace amounts of Ce significantly refine the alloy grain size;•The addition of trace amounts of Ce improves the corrosion resistance of the alloy;•The strong surface activity of Ce inhibits the ...adsorption of Cl− on the metal surface；
The impact of trace Ce doping on the pitting behavior of Fe40Ni20Co20Cr20 high-entropy alloy in a 3.5 wt% NaCl solution was examined. The results indicate that the addition of trace Ce elements leads to a notable reduction in grain size and improved corrosion resistance of the alloy, the critical pitting potential of the alloy increased to 428 mv, and the corrosion resistance of the passivation film was significantly enhanced. This improvement can be mainly attributed to the strong surface activity of Ce, which promotes the formation of Cr2O3 in the passivation film, resulting in a more stable and protective film layer. The ΔE (difference between corrosion potential and zero charge potential) of the high-entropy alloys (HEAs) was negative, indicating a decrease in the adsorption capacity of the electrochemical interface for Cl−. This reduction helps to mitigate pitting corrosion on the surface of the passivation film caused by Cl− erosion.
The influence of an applied mechanical pressure on the electrochemical performance and the aging of 1.4 Ah graphite/NMC622 stacked Lithium-ion battery cells (LiBs) is investigated comprehensively on ...the electrode and the full cell level. Pressure dependent ionic pore resistance measurements reveal an increase of the ionic pore resistance in both, the anode and the cathode of 6% and 2.9%, respectively at a pressure of 0.84 MPa. Compressibility measurements expose an interesting nonlinearity of the compressibility and the number of layers in an electrode stack, which must be considered for the cell application. The applied pressure improves the electrical contact in the cell. However, by the increase of both, the ionic pore resistance and the charge transfer resistance, the reversible capacity loss is strongly dependent on the applied C-rate during the cycling. For C-rates above 0.8C the polarization losses of the compressed cells are around 7.3% in comparison to 2.1% for the uncompressed cells. Contrariwise, for C-rates below 0.8C the compression of the cells is beneficial and leads to a capacity increase of 2.0% compared to the uncompressed cells. The subsequent post-mortem analysis demonstrates the negative influence of the absence of a homogeneous pressure distribution within the uncompressed cells.
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•Mechanical pressure improves the electrical contact in Li-ion batteries.•Reduced ionic pore resistance gets dominant in compressed cells at high C-rates.•Compressibility is strongly dependent on the number of layers.•Uncompressed Li-ion batteries tend to Li deposition.
The inhibition action of Aloe Vera leaf extract as environmentally friendly inhibitor for the corrosion protection of stainless steel in 1M H2SO4 solution was studied by electrochemical techniques as ...well as scanning electron microscope. The results of linear polarization and electrochemical impedance spectroscopy proved the effectiveness of Aloe Vera extract as concentration increased. Corrosion inhibition of Aloe extract was also studied by electrochemical noise (EN). Employing EN, different aspects like transient analysis, noise resistant and characteristic charge were characterized. Moreover, a literature review of Aloe Vera characterization using high-performance liquid chromatography and GC-MS was carried out.
This paper outlines a simple label-free sensor system for the sensitive, real time measurement of an important protein biomarker of sepsis, using a novel microelectrode integrated onto a needle ...shaped substrate. Sepsis is a life threatening condition with a high mortality rate, which is characterised by dysregulation of the immune response following infection, leading to organ failure and cardiovascular collapse if untreated. Currently, sepsis testing is typically carried out by taking blood samples which are sent to a central laboratory for processing. Analysis times can be between 12 and 72 h making it notoriously difficult to diagnose and treat patients in a timely manner. The pathobiology of sepsis is becoming increasingly well understood and clinically relevant biomarkers are emerging, which could be used in conjunction with a biosensor to support real time diagnosis of sepsis. In this context, microelectrodes have the analytical advantages of reduced iR drop, enhanced signal to noise ratio, simplified quantification and the ability to measure in hydrodynamic situations, such as the bloodstream. In this study, arrays of eight (r = 25 µm) microelectrodes were fabricated onto needle shaped silicon substrates and electrochemically characterised in order to confirm successful sensor production and to verify whether the observed behaviour agreed with established theory. After this, the electrodes were functionalised with an antibody for interleukin-6 (IL-6) which is a protein involved in the immune response to infection and whose levels in the blood increase during progression of sepsis. The results show that IL-6 is detectable at physiologically relevant levels (pg/mL) with incubation times as short as 2.5 min. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) measurements were taken and DPV was concluded to be the more suitable form of measurement. In contrast to the accepted view for macro electrodes that the impedance increases upon antigen bind, we report herein a decrease in the micro electrode impedance upon binding. The small size of the fabricated devices and their needle shape make them ideal for either point of care testing or insertion into blood vessels for continuous sepsis monitoring.
•An array of 8 × 50 µm gold electrodes were fabricated onto a needle shaped substrate.•The device was electrochemically characterised to confirm successful fabrication and demonstrate microelectrode behaviour.•Interleukin 6 (IL-6) antibody was immobilised onto the electrode surface.•EIS & DPV measurements were demonstrated as effective methods for detection of antibody- antigen binding.•A dose response curve was established showing IL-6 could be measured at normal and elevated levels using DPV.
Impedance spectra of a high energy lithium-ion battery (graphite vs. NMC) are investigated in detail, using the distribution of relaxation times (DRT) and complementary methods. Two predominant ...processes are found, one at lower frequencies and one at moderate frequencies. By investigating impedance spectra of corresponding half-cells (graphite vs. Li and NMC vs. Li), it is found that the process at lower frequencies can clearly be assigned to the NMC's charge transfer. Further, it is assumed that the process at moderate frequencies is correlated to the graphite's solid electrolyte interphase (SEI). However, the relevant frequency-range of the anode half-cell is seemingly overshadowed by the lithium counter-electrode and thus cannot be investigated properly. To investigate this issue, symmetrical lithium cells are build and their impedance spectra are investigated as well. Indeed, the lithium's main-process occurs at the presumed frequencies. Eventually, a combination of several measurements and analyses show that the process at moderate frequencies is correlated to the graphite's SEI. Among these are i) an investigation of a calendric aged commercial cell and its corresponding half-cells and ii) a differential regression analysis (DRA), which is established in this work and proved to be a powerful analysis-tool.
•Separation of impedance processes of a commercial lithium-ion battery (NMC vs. graphite).•Impedance spectra of graphite half-cells and NMC half-cells over a wide SOC-range.•Impedance spectra of a symmetrical lithium cell after several charge/discharge processes.
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