Cathodic Peak Research Articles

Optimization of graphene dose for improved electrochemical performance of silicon–graphene negative electrodes in lithium batteries

Different percentages of nanoparticles graphene (G) were mixed with nano-micron sized silicon (Si) particles as follows: 10, 20, 30 and 40 wt% graphene to silicon ratios. The crystal structure of pure Si powder pattern has cubic phase SEM, TEM/SAED and XPS equipments were implemented to study the surface properties of the prepared G@Si composites. Cyclic voltammetry (CV) measurement for the G@Si cell revealed two broad cathodic peaks, related to the deposition of Li2O thin layer on Si particles and the lithiation process of Si to form lithium silicide. Meanwhile, the oxidation of LixSi into Si and Li ionis confirmed by the anodic strong peak at 0.56 V. Electrochemical impedance spectroscopy (EIS) measurements revealed high interfacial resistance ~ 1825 Ω for pure Si anode in comparison with that of G@Si composite anode. It is concluded that graphene acts as a conductive shielding pathway to inhibit the large volume change and minimize the capacity fading during successive galvanostatic cycling of G@Si composite anode materials versus Li/Li+. Accordingly, the specific discharge capacity of 30%G@Si cell delivered about 1240 and 900 mAhg−1 for 1st and 100th charge–discharge cycles, respectively.

Cyclic Voltammetry of Screen-Printed Carbon Electrode Coated with Ag-ZnO Nanoparticles in Chitosan Matrix.

In this paper, the authors describe the fabrication of nanocomposite chitosan-based systems of zinc oxide (ZnO), silver (Ag) and Ag-ZnO. Recently, the development of coated screen-printed electrodes using metal and metal oxide nanoparticles (NPs) for the specific detection and monitoring of different cancer tumors has been obtaining important results. Ag, ZnO NPs and Ag-ZnO prepared by the hydrolysis of zinc acetate blended with a chitosan (CS) matrix were used for the surface modification of screen-printed carbon electrodes (SPCEs) in order to analyze the electrochemical behavior of the typical redox system of a 10 mM potassium ferrocyanide-0.1 M buffer solution (BS). The solutions of CS, ZnO/CS, Ag/CS and Ag-ZnO/CS were prepared in order to modify the carbon electrode surface, and were measured at different scan rates from 0.02 V/s to 0.7 V/s by cyclic voltammetry. The cyclic voltammetry (CV) was performed on a house-built potentiostat (HBP). The cyclic voltammetry of the measured electrodes showed the influence of varying the scan rate. The variation of the scan rate has an influence on the intensity of the anodic and cathodic peak. Both values of currents (anodic and cathodic currents) have higher values for 0.1 V/s (Ia = 22 μA and Ic = -25 μA) compared to the values for 0.06 V/s (Ia = 10 μA and Ic = -14 μA). The CS, ZnO/CS, Ag/CS and Ag-ZnO/CS solutions were characterized using a field emission scanning electron microscopy (FE-SEM) with EDX elemental analysis. The modified coated surfaces of screen-printed electrodes were analyzed using optical microscopy (OM). The present coated carbon electrodes showed a different waveform compared to the voltage applied to the working electrode, depending on the scan rate and chemical composition of the modified electrodes.

Electrochemical activity of tungsten oxide doped carbon (WO3/C) catalyst for hydroquinone/benzoquinone redox flow battery

The research in organic flow batteries is emerging as the cost of the vanadium electrolyte limits the grid-scale application. Tungsten trioxide doped carbon (WO3/C) electrocatalyst is developed to examine its potential in hydroquinone - benzoquinone redox flow battery (HQ/BQ RFB). The catalyst is characterized by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR) and confirms the formation of active WO3/C electrocatalyst. The electrochemical activity of the synthesized WO3/C electrocatalyst is inspected by cyclic voltammetry (CV). It shows comparatively high anodic and cathodic peak currents, low charge transfer resistance, and relatively high electrokinetic reversibility. The charge–discharge test on single cell HQ/BQ RFB is conducted using pristine carbon paper (CP), and WO3/C coated carbon paper (WO3/C-CP). The columbic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of the RFB using WO3/C-CP are around 90%, 75%, and 70%, respectively, which are significantly higher than the CP. The improvement in results demonstrates that the WO3/C electrocatalyst is better at providing active sites and improving the electrochemical reactions kinetics, thus suits the application of HQ/BQ RFB.

Unconventional Electrochemical Behaviors of Cu Underpotential Deposition in a Chloride-Based Deep Eutectic Solvent: High Underpotential Shift and Low Coverage.

The (5 × 5) Moiré pattern resulting from coadsorption of Cu atoms and chloride ions on the Au(111) electrode is one of the most classical structures for underpotential deposition (UPD) in electrochemical surface science. Although two models have been proposed to describe the pattern, the details of the structure remain ambiguous and controversial, leading to a question that remains to be answered. In this work, we investigate the UPD behaviors of Cu on the Au(111) electrode in a chloride-based deep eutectic solvent ethaline by in situ scanning tunneling microscopy (STM). Benefiting from the properties of the ultraconcentrated electrolyte, we directly image not only Cu but also Cl adlayers by finely tuning tunneling conditions. The structure is unambiguously determined for both Cu and Cl adlayers, where an incommensurate Cu layer is adsorbed on the Au(111) surface with a Cu coverage of 0.64, while the Cl coverage is 0.32 (only half of the expected value); i.e., the atomic arrangement of the observed (5 × 5) Moiré pattern in ethaline matches neither of the models proposed in the literature. Meanwhile, STM results confirm the origin of the cathodic peak in the cyclic voltammogram, which indicates that the underpotential shift of Cu UPD in ethaline indeed increases by ca. 0.40 V compared to its counterpart in a sulfuric acid solution, resulting in a significant deviation from the linear relation between the underpotential shift and the difference in work functions proposed in the literature. The unconventional electrochemical behaviors of Cu UPD reveal the specialty of both the bulk and the interface in the chloride-based deep eutectic solvent.

Electrochemical Behavior of Nanocrystalline NiMoO<sub>4</sub> Hydrate Modified by Ultrasound

To improve the specific capacitance, power and energy of electrical energy storage devices, in particular hybrid capacitors, various methods of cathode material modification are used. One of the methods of modifying nanostructured materials without applying high temperatures, pressures and long reaction times is ultrasonic treatment. Although the interaction of ultrasound with the structure and surface of electrode materials is well enough studied, there are few works that investigate the optimal duration of ultrasonic treatment and its relationship with the capacitive characteristics of these materials. Therefore, we investigated the efficiency of ultrasonic dispersion of nanocrystalline nickel molybdate hydrate for 15, 60 and 90 minutes. The appearance of two cathodic peaks on cyclic voltammetry patterns was analyzed and the charge / discharge mechanism of the electrode based on nanocrystalline NiMoO4 hydrate was presented. Based on the results of potentiodynamic and galvanostatic studies the specific capacitances of the initial NiMoO4 and the material modified by ultrasound for 15, 60 and 90 minutes were calculated. The proton diffusion coefficients of nickel molybdate hydrate were determined on the basis of the Randles–Sevcik equation. NiMoO4 subjected to ultrasonic dispersion for 60 min as a cathode material in a hybrid electrochemical system was tested.

Development of an electrochemical medetomidine nanosensor based on N and P-doped carbon nano-onions, MoS2, and poly (melamine) nanocomposite

Medetomidine is one of the anesthesia drugs that is primarily used by veterinary. This drug has analgesic effects too. In this work, a screen-printed carbon electrode (SPCE) was modified by a composite of N and P-doped carbon nano-onions (N,P-CNO), MoS2, and poly (melamine) (PME) (SPCE/N,P-CNO/MoS2/PME). First, synthesized nanomaterials and fabricated electrodes were evaluated and analyzed by FT-IR, FE-SEM, and XRD techniques. Then, the voltammetric response of medetomidine was evaluated using SPCE/N,P-CNO/MoS2/PME. A cathodic peak appeared in a buffered solution with pH = 7.0 containing medetomidine. The synergetic effect of N,P-CNO and MoS2, providing wide active surface area, and PME as an electron conduction booster enhanced the modified electrode response toward medetomidine. The limit of detection of 10 nM was achieved for medetomidine in the concentrations range of 0.04 to 700 μM. The SPCE/N,P-CNO/MoS2/PME was able to determine the medetomidine concentration in mouse blood samples accurately with 90–98.2 % recovery.

BN/Cu/CNT nanoparticles as an efficient tri-functional electrocatalyst for ORR and OER

Preparing economic, stable, and highly efficient non-precious-metal materials for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great significance to the development of storage technologies and energy conversion. In this manuscript, we report a novel Cu based nano-catalyst as an electrode material fabricated by complexation-reduction method. Benefit from the stable of h-NB and the good electrical conductivity of CNT, the tri-functional electrocatalyst BN/Cu/CNT displays enhanced activity towards ORR and with the high current density of 0.95 mA/cm2, which is comparable to that of commercial Pt/C catalyst (cathodic peak current: 1.05 mA/cm2). The BN/Cu/CNT also demonstrates high catalyst activity for the OER. From the rotating disk electrode and rotating ring-disk electrode tests, the number of electrons exchanged during the ORR is revealed to be 3.92, suggesting a 4e− pathway of O2 reduction to H2O. The as prepared catalyst also has good stability and superior methanol tolerance to the commercial Pt/C catalyst in alkaline medium. Thus, it is anticipated that the BN/Cu/CNT catalyst is surely helpful for providing a new space to develop Pt-free catalyst.

Impedimetric nanoimmunosensor platform for aflatoxin B1 detection in peanuts.

This article developed a novel electrochemical immunosensor for the specific detection of aflatoxin B1 (AFB1). Amino-functionalized iron oxide nanoparticles (Fe3 O4 -NH2 ) were synthesized. Fe3 O4 -NH2 were chemically bound on self-assembly monolayers (SAMs) of mercaptobenzoic acid (MBA). Finally, polyclonal antibodies (pAb) were immobilized on Fe3 O4 -NH2 -MBA. The sensor system was evaluated through atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A reduction in the anodic and cathodic peak currents was observed after the assembly of the sensor platform. The charge transfer resistance (Rct ) was increased due to the electrically insulating bioconjugates. Then, the specific interaction between the sensor platform and AFB1 blocks the electron transfer of the [Fe(CN)6 ]3-/4- redox pair. The nanoimmunosensor showed a linear response range estimated from 0.5 to 30 μg/mL with a limit of detection (LOD) of 9.47 μg/mL and a limit of quantification (LOQ) of 28.72 μg/mL for AFB1 identification in a purified sample. In addition, a LOD of 3.79 μg/mL, a LOQ of 11.48 μg/mL, and a regression coefficient of 0.9891 were estimated for biodetection tests on peanut samples. The proposed immunosensor represents a simple alternative, successfully applied in detecting AFB1 in peanuts, and therefore, represents a valuable tool for ensuring food safety.

Binding-Induced Folding of DNA Oligonucleotides Targeted to the Nucleocapsid Gene Enables Electrochemical Sensing of SARS-CoV-2.

In the wake of the COVID-19 pandemic, millions of confirmed cases and deaths have been reported around the world. COVID-19 spread can be slowed and eventually stopped by a rapid test to diagnose positive cases of the disease on the spot. It is still important to test for COVID-19 quickly regardless of the availability of the vaccine. Using the binding-induced folding principle, we developed an electrochemical test for detecting SARS-CoV-2 with no RNA extraction or nucleic acid amplification. The test showed high sensitivity with a limit of detection of 2.5 copies/μL. An electrode mounted with a capture probe and a portable potentiostat are used to conduct the test. To target the N-gene of SARS-CoV-2, a highly specific oligo-capturing probe was used. Based on the binding-induced "folding" principle, the sensor detects binding between the oligo and RNA. When the target is absent, the capture probe tends to form a hairpin as a secondary structure, retaining the redox reporter close to the surface. This can be seen as a large anodic and cathodic peak current. When the target RNA is present, the hairpin structure will open to hybridize with its complementary sequence, causing the redox reporter to pull away from the electrode. Consequently, the anodic/cathodic peak currents are reduced, indicating the presence of the SARS-CoV-2 genetic material. Validation of the test performance was performed using 122 COVID-19 clinical samples (55 positives and 67 negatives) and benchmarked to the gold standard reverse transcription-polymerase chain reaction (RT-PCR) test. As a result of our test, the accuracy, sensitivity, and specificity have been measured at 98.4%, 98.2%, and 98.5%, respectively.

3D printed electrodes design and voltammetric response

The limiting aspects in the voltammetric response of 3D printed electrodes is thoroughly investigated with numerical simulations and new 3D printed electrode designs. Severe diffusion limitations, resulting from a recessed electrode geometry, is found in a commonly used 3D printed electrode and electrochemical cell design, impeding the investigation of electron transfer kinetics at these electrodes by classical methods, such as Nicholson's, widely used on this and similarly mass transport-limited designs. A new 3D printed electrode design, an inlaid disk (non-recessed) geometry, is used to investigate the voltammetric response of printed electrodes in bulk solution, i.e., without mass transport limitations. At this condition, it is clear that the voltammetric response is limited by contact resistance, arising from the printed material low electrical conductivity. Gold modified electrodes, deliberately designed with different contact resistances, highlight the resistive behavior, with quasi-reversible voltammetric profiles. This contrasts with the common assumption of a voltammetric response limited by finite electron kinetics. Electron transfer rate constants (k0) and transfer coefficients (α) for electrodes with and without surface modifications are calculated from experimental data using a modified Butler-Volmer equation, incorporating ohmic losses. The reported k0 and α values are independent of electrode geometry or printing parameters, unlike the observable rate constant usually reported for 3D printed electrodes. By accounting for contact resistance and finite electron transfer kinetics, cathodic and anodic peak potentials and currents of voltammograms recorded with 3D printed electrodes are predicted before printing, allowing electrode designs to be optimized in the virtual space.

Electro-kinetic investigations and voltammetric detection of anti-ulcer drug cinitapride at low-cost pencil graphite electrode

Herein, we proposed a cost-effective, eco-friendly, fast and sensitive square wave cathodic stripping voltammetry (SWCSV) and differential pulse cathodic stripping voltammetry (DPCSV) methods for the quantification of anti-ulcer drug cinitapride in pharmaceuticals. Cinitapride electrochemically reduced at pencil graphite electrode and gave an irreversible well-defined cathodic peak in cyclic, square wave, and differential pulse voltammograms. The effect of pH of buffer, scan rates, and drug concentration on peak current and peak potential were studied. The reduction of cinitapride at pencil graphite electrode was diffusion controlled and occurred via participation of two electrons and two protons (2e−/2H+). The various electro-kinetic parameters such as diffusion coefficient(Do), surface coverage (T o)and electron transfer coefficient (α) were calculated, additionally, the mechanism of reduction of cinitapride at pencil graphite electrode was also proposed. The peak currents vary linearly in the concentration range 2.48 μmolL−1 to 17.39 μmolL−1 for all the voltammetric techniques. The obtained value of LOD for SWCSV and DPCSV techniques were2.48 μmolL−1 and 3.19 μmolL−1, respectively, which proved higher sensitivity of the proposed methods.

Noble-Metal-Free Zinc Oxide Nanoparticle Electrodes for Electrochemical Detection of Benzene-Derived Compounds: 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and diphenylamine

Zinc oxide nanoparticle electrode catalysts were used to electrochemically examine benzene-derived compounds by controlling geometric factors (particle size and oxide-layer thickness) to measure the detection sensitivity difference. Spin-coating was performed to control the nanoparticle layer thickness. First, a representative benzene-derived compounds (2,4,6-trinitrotoluene) was detected using cyclic voltammetry. Three main cathodic reduction peaks were confirmed in the range of −0.5 to −0.9 V (vs Ag/AgCl in 3 M KCl). 50 nm diameter and ∼2 μm thickness of zinc oxide nanoparticles appeared the best detection performance, due to the surface uniformity, high surface area, and electric conductivity. Two additional benzene-derived compounds (2,4-dinitrotoluene and diphenylamine) were utilized to measure the detectability of the zinc oxide nanoparticle layers. Consequently, 2,4-dinitrotoluene and diphenylamine were detected using cyclic voltammetry. The mass transfer of these three benzene-derived compounds affected the diffusion- and surface-controlled processes. Finally, the limits of detection, quantitation, and sensitivity of the benzene-derived compounds were recorded using differential pulse voltammetry. The results indicated that adjusting the geometric factor is a competitive method for enhancing the detection sensitivity. Moreover, this work can be extended to detect diverse benzene-derived compounds such as diazonitrophenol, nitrocellulose, picric acid, and tetryl.

Comparison study of WO3 thin film and nanorods for smart window applications

The WO3 thin films were deposited at oxygen partial pressure of 8x10-4 mbar. A template-free straightforward hydrothermal method is employed to produce vertical alignment hierarchical WO3 nano-architectures on clear conducting substrates (3x2.5 cm2 in size and slides resistance 4 O). After being deposited at ambient temperature, the samples were air annealed at 400 °C for 4 h. The optical, electrochromic, surface and structural morphology behavior of the deposited material after annealing were studied using XRD, Raman, FTIR, SEM, electrochemical analyzer and UV–Visible spectrometer characterization methods. After annealing at 400 °C for 4 h in air, every characteristic peak are matched to a monoclinic (crystalline) WO3 phase. The Nano flower array achieved a considerable coloration efficiency (24.09 cm2/s) and low cathodic peak current (−2.03 mA) compare to the Tungsten trioxide thin film produced by the DC magnetron sputtering method. The vertically oriented geometry and the porosity space between the Nano flower, which improve H+ diffusion and provide a considerable contact area for charge-transfer processes, are primarily responsible for the improved electrochromic properties.

Multi response optimization of waste activated sludge oxidation and azo dye reduction in microbial fuel cell

ABSTRACT Microbial fuel cell technology draws attention with its ability to directly recover electrical energy from various organic materials. In this study, the operating conditions affecting the oxidation–reduction and electricity generation efficiency of MFC were optimized using the Taguchi Experimental Design model. Optimization was carried out for maximum power density, coulombic efficiency, azo dye removal, and COD removal. With the determined optimum conditions (cathode pH of 3.0, cathode oxygen status of anaerobic, anode substrate of pre-treated, external resistance of 100 Ω, cathode electrode type of plain carbon, cathode electrode surface of 22 cm2, cathode conductivity of 20 µs/cm), 177.03 mW/m2 power density, 7.50% coulombic efficiency, 91.26% azo dye removal efficiency and 21.61% COD removal efficiency were obtained. By Pareto analysis, it was determined that the power density, coulombic efficiency and COD removal efficiency were most affected by the substrate type at the anode, and the azo dye removal was most affected by the catholyte pH. The maximum power density and internal resistance of the MFC operated under optimum conditions were determined as 145.11 mW/m2 and 243.30 Ω, respectively by the polarization curve. Cyclic voltammetry was also performed for the electrochemical characterization of MFC operated under optimum conditions. An anodic peak at −183.2 mV and a cathodic peak at −181.2 mV was visible in the CV curve.

Impact of 1,8-Diiodooctane (DIO) Additive on the Active Layer Properties of Cu2ZnSnS4 Kesterite Thin Films Prepared by Electrochemical Deposition for Photovoltaic Applications

Kesterite Cu2ZnSnS4 (CZTS) thin films using various 1,8-diiodooctane (DIO) polymer additive concentrations were fabricated by the electrochemical deposition method. The optical, electrical, morphological, and structural properties of the CZTS thin films synthesized using different concentrations of 5 mg/mL, 10 mg/mL, 15 mg/mL, and 20 mg/mL were investigated using different techniques. Cyclic voltammetry exhibited three cathodic peaks at -0.15 V, -0.54 V, and -0.73 V, corresponding to the reduction of Cu2+, Sn2+, Sn2+, and Zn2+ metal ions, respectively. The analysis of the X-ray diffraction (XRD) pattern indicated the formation of the pure kesterite crystal structure, and the Raman spectra showed pure CZTS with the A1 mode of vibration. Field emission scanning electron microscopy (FE-SEM) indicated that the films are well grown, with compact, crack-free, and uniform deposition and a grain size of approximately 4 µm. For sample DIO-20 mg/mL, the elemental composition of the CZTS thin film was modified to Cu:Zn:Sn: and S = 24.2:13.3:12.3:50.2, which indicates a zinc-rich and copper-poor composition. The X-ray photoelectron spectroscopy (XPS) results confirmed the existence of Cu, Sn, Zn, and S elements and revealed the element oxidation states. The electrochemical deposition synthesis increased the absorption of the CZTS film to more than 104 cm-1 with a band gap between 1.62 eV and 1.51 eV. Finally, the photovoltaic properties of glass/CZTS/CdS/n-ZnO/aluminum-doped zinc oxide (AZO)/Ag solar cells were investigated. The best-performing photovoltaic device, with a DIO concentration of 20 mg/mL, had a short-circuit current density of 16.44 mA/cm2, an open-circuit voltage of 0.465 V, and a fill factor of 64.3%, providing a conversion efficiency of 4.82%.

Gellan Gum-Montmorillonite Nanocomposites for Electrochromic Devices

The present paper shows the results of nanocomposite polymer electrolytes (SPEs) of montmorillonite (MMT; Na+SYN-1) and gellan gum obtained by the solution casting method. The membrane samples were characterized by ATR-FTIR, time-domain nuclear magnetic resonance (TD-NMR), and scanning electron microscopy (SEM). Then, two samples were chosen and applied in small electrochromic devices (ECDs). The ATR-FTIR revealed shifts in bands of acetate and glycosidic bonds at 1032 and 1611 cm−1, respectively, indicating an interaction between the gellan gum and Na+SYN-1. The spin–lattice relaxation time of the proton nuclei (T1) suggests the poor dispersion of MMT in the matrix, especially above 20 wt.%. However, SEM pictures pointed to a more homogeneous surface of the nanocomposite containing 40 wt.% Na+SYN-1 when compared to the sample without clay. NPEs with 10 and 40 wt.% Na+SYN-1 were applied in ECDs, and the voltammograms showed a decrease in anodic and cathodic peaks after 2519 chronocoulometric cycles for the sample with 10 wt.% Na+SYN-1 and after 420 cycles for the sample with 40 wt.% Na+SYN-1. There was also a decrease in the charge density in both ECDs and an oscillating difference in transmittance between the colored/discolored states during the chronocoulometric cycles of the ECD with GG-MMT10. Further studies may reveal more property improvements in gellan gum nanocomposites.

2H-MoS 2 Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

2H-MoS ₂ Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

Titanium-Based Static Mixer Electrodes to Improve the Current Density of Slurry Electrodes.

Complex geometries for electrodes are a great challenge in electrochemical applications. Slurry electrodes have been one example, which use complex flow distributors to improve the charge transfer between the current collector and the slurry particles. Here we use titanium-based flow distributors produced by indirect 3D-printing to improve further the electron transfer from highly conductive flow distributors to the slurry particles for a vanadium redox flow application. The titanium static mixers are directly coated with graphite to increase the activity for vanadium redox reactions. Increasing layers of graphite have shown an optimum for the positive and negative electrolytes. The application of heat treatment on the electrodes improves the anodic and cathodic current peaks drastically. Testing the highly conductive static mixers in a self-made redox flow cell results in 110 mA cm-2 discharge polarization.

Electrochemical Evaluation of Different Graphite Felt Electrode Treatments in Full Vanadium Redox Flow Batteries

The use of flow batteries for energy storage has attracted considerable attention with the increased use of renewable resources. It is well known that the performance of a flow battery depends, among other factors, on the properties of the electrodes, which are generally composed of graphite felt (GF). In this work, thermal, chemical and plasma treatments have been employed to modify the surface of the graphite felt to improve the electrochemical activity of the redox flow cell. The influence of the variables of each of these processes on the generation of surface functional groups and on changes in the obtained surface area have been examined. In this work, the kinetics of redox reactions relevant to the VO2+/VO2+ reaction have been studied with these treated electrodes and the relationship between the nature of the surface and electrochemical activity of the GF is discussed. As a result, an enhanced electrochemical performance (reduction over 200 mV of the separation between anodic and cathodic peaks and 110 mV of the onset potential) in comparison to the untreated GF is obtained for those GF treatments with low oxygenated groups concentration.

Silver nanoparticle doped graphene-based impedimetric biosensor towards sensitive detection of procalcitonin

In the early detection of sepsis, procalcitonin (PCT) appears to be a highly sensitive biomarker for severe inflammation and infection. A significant interaction between the electrode material to be used in the design of the biosensor and the material to be attached to the surface is of great importance. Here, we demonstrated a silver nanoparticle (AgNp) doped graphene-based sensitive PCT biosensor with low-cost, environmentally friendly materials. Cyclic voltammetry curves showing the reusability of the electrodes obtained were obtained and showed antibody-protein adhesion on the AgNp/SLG@ITO surface. The anodic and cathodic peak currents values after 20 cycles show that these values are suitable even after 20 measurements. Electrochemical impedance spectroscopy (EIS) studies confirmed the effects of PCT on binding events due to increasing concentration at a constant PCT-antibody concentration. The limit of detection (LOD) value of the fabricated PCT/Ab/AgNp/SLG@ITO impedimetric biosensor was determined as 0.55 ngmL−1. The low LOD value can be attributed to the uniform and large surface area of single-layer graphene (SLG) and noble AgNp. The LOD value based on the EIS studies has revealed that the PCT/Ab/AgNp/SLG@ITO impedimetric biosensor can be employed in real samples.