scholarly journals Semiconducting bacterial biofilm based on graphene-MoS2 template and component dependent gating behavior

2020 ◽  
Author(s):  
Sanhita Ray ◽  
Arpita Das ◽  
Anjan Kr Dasgupta
Keyword(s):  
Current Flow ◽  
Electrochemical Impedance ◽  
Bacterial Biofilm ◽  
Bandgap Energy ◽  
Mos2 Nanosheets ◽  
Ftir Studies ◽  
Current Voltage ◽  
Bode Plots ◽  
Bulk Mos2 ◽  
First Time

AbstractIn this paper, we report for the first time, the synthesis of a semiconducting biofilm. Photosynthetic bacterial biofilm has been used to weave together MoS2 nanosheets into an adherent film grown on interdigitated electrodes. Liquid-phase exfoliation of bulk MoS2 powder was used to obtain MoS2 nanosheets. A synchronous-fluorescence scan revealed the presence of two emission maxima at 682nm and 715nm for the MoS2 suspension. Such maxima with bandgap energy 1.82 and 1.73 eV corresponded to the single and double layer of MoS2. The presence of such single and multi-layered structures was confirmed by Raman spectroscopy, FTIR studies, and electron microscopy. The current-voltage (I-V) studies of such a bio-nano hybrid revealed the emergence of the gated nature of the current flow. This Schottky diode like behavior, reported earlier for Graphene-biofilm junctions, is also observed in this case. Gating voltage depended on the composition of the biofilm. The semiconductor biofilms, when studied using electrochemical impedance spectroscopy, revealed characteristic Nyquist and Bode plots, suggesting special circuit-equivalence for each film. While Mos2 was marked with stability with respect to variations in RMS voltage and bias voltage, the graphene biofilm was unique by the absence of any Warburg element.

scholarly journals Protection of Petroleum Pipeline Carbon Steel Alloys with New Modified Core-Shell Magnetite Nanogel against Corrosion in Acidic Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Gamal A. El Mahdy ◽  
Ayman M. Atta ◽  
Amro K. F. Dyab ◽  
Hamad A. Al-Lohedan
Keyword(s):  
Carbon Steel ◽  
Sulfonic Acid ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Core Shell ◽  
Magnetite Nanoparticle ◽  
Potassium Peroxydisulfate ◽  
Redox Initiator ◽  
Initiator System ◽  
First Time

New method was used to prepare magnetite nanoparticle based on reduction of Fe(III) ions with potassium iodide to produce Fe3O4nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been developed for the first time. The polymer was crosslinked in the presence of N,N-methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as redox initiator system. The structure and morphology of the magnetic nanogel were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations. The results showed that the nanogel particles act as mixed inhibitors. EIS data revealed thatRctincreases with increasing inhibitor concentration.

scholarly journals A High Capacity, Room Temperature, Hybrid Flow Battery Consisting of Liquid Na-Cs Anode and Aqueous NaI Catholyte

Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 60 ◽  
Author(s):  
Caihong Liu ◽  
Leon Shaw
Keyword(s):  
Room Temperature ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
High Capacity ◽  
High Energy ◽  
Flow Battery ◽  
Membrane Interfaces ◽  
Number Of Cycles ◽  
Novel Concept ◽  
First Time

In this study, we have proposed a novel concept of hybrid flow batteries consisting of a molten Na-Cs anode and an aqueous NaI catholyte separated by a NaSICON membrane. A number of carbonaceous electrodes are studied using cyclic voltammetry (CV) for their potentials as the positive electrode of the aqueous NaI catholyte. The charge transfer impedance, interfacial impedance and NaSICON membrane impedance of the Na-Cs ‖ NaI hybrid flow battery are analyzed using electrochemical impedance spectroscopy. The performance of the Na-Cs ‖ NaI hybrid flow battery is evaluated through galvanostatic charge/discharge cycles. This study demonstrates, for the first time, the feasibility of the Na-Cs ‖ NaI hybrid flow battery and shows that the Na-Cs ‖ NaI hybrid flow battery has the potential to achieve the following properties simultaneously: (i) An aqueous NaI catholyte with good cycle stability, (ii) a durable and low impedance NaSICON membrane for a large number of cycles, (iii) stable interfaces at both anode/membrane and cathode/membrane interfaces, (iv) a molten Na-Cs anode capable of repeated Na plating and stripping, and (v) a flow battery with high Coulombic efficiency, high voltaic efficiency, and high energy efficiency.

scholarly journals Electrochemical Impedance of Hydrogenated Phases of ZnO and CuO Nanoparticles for Electrode Applications

2020 ◽  
pp. 1-6
Author(s):  
L. I. Menegbo ◽  
J. L. Konne ◽  
N. Boisa
Keyword(s):  
Electrochemical Impedance ◽  
Sol Gel ◽  
Low Frequency ◽  
High Gain ◽  
High Frequency Region ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Xrd Patterns ◽  
Straight Lines ◽  
First Time

The Electrochemical Impedance Spectroscopy (EIS) measurements of Sol-gel synthesized ZnO, CuO and their respective hydrogenated phases (ZnO:H and CuO:H) for  a proton-type battery model has been reported for the first time. The XRD patterns confirmed that CuO and ZnO were phase pure with minor impurities. However, that of CuO:H showed mixed phases of CuO and Cu2O with the later  appearing prominent. The estimated particle sizes of ZnO, ZnO:H, CuO and CuO:H obtained using Scherrers’ equation were 17.83, 17.75, 21.63 and 15.42 nm respectively, showing remarkable particle size reductions upon hydrogenation as oxygen vacancies were substituted with smaller hydrogen ions. Nyquist plots from the EIS experimental data recorded over a frequency range of 100 kHz – 5 mHz showed expected flat semicircles at the high frequency region and straight lines at the low frequency regions while resistance estimations from the intercepts of the Bode plots were 12.10, 7.80, 16.00 and 10.80 Ω for ZnO, ZnO:H, CuO and CuO:H respectively. It also indicated high gain margins suggesting impressive electrochemical properties for battery applications.

scholarly journals Исследование механизмов токопрохождения в гетероструктуре CdS/por-Si/p-Si

2018 ◽  
Vol 52 (7) ◽  
pp. 751
Author(s):  
В.В. Трегулов ◽  
В.Г. Литвинов ◽  
А.В. Ермачихин
Keyword(s):  
Current Flow ◽  
Energy Band Diagram ◽  
Band Diagram ◽  
Current Voltage Characteristic ◽  
Semiconductor Heterostructure ◽  
Current Voltage ◽  
Recombination Processes ◽  
Flow Mechanisms ◽  
Carrier Tunneling ◽  
Space Charge Limited Currents

AbstractThe temperature dependence of the forward and reverse portions of the current–voltage characteristic and the photovoltage spectrum of a CdS/ por -Si/ p -Si semiconductor heterostructure are studied. It is found that the current-flow mechanisms are controlled by generation–recombination processes in the spacecharge region of the por -Si/ p -Si heterojunction, carrier tunneling in the por -Si film, and the model of space-charge-limited currents. A simplified version of the energy-band diagram of the heterostructure under study is proposed.

scholarly journals Antimicrobial Synergy of Silver-Platinum Nanohybrids With Antibiotics

2021 ◽  
Vol 11 ◽  
Author(s):  
Bansi Ranpariya ◽  
Gayatri Salunke ◽  
Srikanta Karmakar ◽  
Kaushik Babiya ◽  
Santosh Sutar ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacterial Infections ◽  
Bacterial Biofilm ◽  
Antimicrobial Drugs ◽  
Mortality And Morbidity ◽  
Green Route ◽  
Antimicrobial Synergy ◽  
First Time ◽  
Tuber Extract ◽  
Powerful Strategy

Various bacterial pathogens are responsible for nosocomial infections resulting in critical pathophysiological conditions, mortality, and morbidity. Most of the bacterial infections are associated with biofilm formation, which is resistant to the available antimicrobial drugs. As a result, novel bactericidal agents need to be fabricated, which can effectively combat the biofilm-associated bacterial infections. Herein, for the first time we report the antimicrobial and antibiofilm properties of silver-platinum nanohybrids (AgPtNHs), silver nanoparticles (AgNPs), and platinum nanoparticles (PtNPs) against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The AgPtNHs were synthesized by a green route using Dioscorea bulbifera tuber extract at 100°C for 5 h. The AgPtNHs ranged in size from 20 to 80 nm, with an average of ∼59 nm. AgNPs, PtNPs, and AgPtNHs showed a zeta potential of −14.46, −1.09, and −11.39 mV, respectively. High antimicrobial activity was observed against P. aeruginosa and S. aureus and AgPtNHs exhibited potent antimicrobial synergy in combination with antibiotics such as streptomycin, rifampicin, chloramphenicol, novobiocin, and ampicillin up to variable degrees. Interestingly, AgPtNHs could inhibit bacterial biofilm formation significantly. Hence, co-administration of AgPtNHs and antibiotics may serve as a powerful strategy to treat bacterial infections.

scholarly journals Evaluation of the Corrosion Resistance of WC-Co Coating on AZ91 Applied by Electro Spark Deposition

2020 ◽  
Vol 20 (1) ◽  
pp. 30-40
Author(s):  
Arvin Taghizadeh Tabrizi ◽  
Maryam Pouzesh ◽  
Farhad Farhang Laleh ◽  
Hossein Aghajani
Keyword(s):  
Corrosion Rate ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Bulk Sample ◽  
Az91 Alloy ◽  
Corrosion Performance ◽  
Surface Microhardness ◽  
Optimum Parameters ◽  
Temperature Polarization ◽  
First Time

Abstract In order to enhance the surface properties of a magnesium-based substrate, WC-Co coating was applied on AZ91 alloy by electro spark deposition (ESD), successfully for the first time. The optimum parameters of the ESD process were achieved, based on the corrosion behavior and calculated corrosion rate of the coated samples when 5kHz and 25 A were chosen. For evaluation of the corrosion performance of the achieved WC-Co layers, polarization, and electrochemical impedance spectroscopy tests were carried out in the 3.5 wt % Na3PO4 solution at room temperature. Polarization results show that the corrosion rate (mpy) is in the optimum condition almost half of a bulk sample of uncoated AZ91. Field emission scanning electron microscopy (FE-SEM) was used to examine the surface morphology of applied coatings. These results show that at a lower current, the amount of deposited WC-Co was reduced. The maximum surface microhardness obtained was 193 HV0.2.

scholarly journals Corrosion Performance of AISI-309 Exposed to Molten Salts V2O5-Na2SO4at 700°C Applying EIS andRpElectrochemical Techniques

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
E. F. Diaz ◽  
C. Cuevas-Arteaga ◽  
N. Flores-García ◽  
S. Mejía Sintillo ◽  
O. Sotelo-Mazón
Keyword(s):  
Molten Salts ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Metallic Surface ◽  
Corrosion Performance ◽  
Potentiodynamic Polarization Curve ◽  
Linear Polarization Resistance ◽  
Second Stage ◽  
Tafel Slopes ◽  
Bode Plots

The corrosion performance of AISI-309 exposed 5 days to molten salts 50 mol% V2O5-50 mol% Na2SO4at 700°C is reported in this paper. Such evaluation was made using three electrochemical techniques: potentiodynamic polarization curve (PC), electrochemical impedance spectroscopy (EIS), and linear polarization resistance (Rp). FromPC, the Tafel slopes,Icorr, andEcorrwere obtained. From Nyquist and Bode plots, it was possible to determine two different stages; the first one showed just one loop, which indicated the initial formation of Cr2O3layer over the metallic surface; after that, the dissolution of Cr2O3formed a porous layer, which became part of the corrosion products; at the same time a NiO layer combined with sulfur was forming, which was suggested as the second stage, represented by two capacitive loops. EIS plots were in agreement with the physical characterization made from SEM and EDS analyses. Fitting of EIS experimental data allowed us to propose two electrical circuits, being in concordance with the corrosion stages. Parameters obtained from the simulation of EIS data are also reported. From the results, it was stated that AISI-309 suffered intergranular corrosion due to the presence of sulfur, which diffused to the metallic surface through a porous Cr2O3layer.

Anomalous change of carrier transport property of ferroelectric Hf0.5Zr0.5O2 thin films in the first poling treatment

2022 ◽  
Author(s):  
Yukinori Morita ◽  
Hiroyuki OTA ◽  
Shinji MIGITA
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Transport Property ◽  
Carrier Transport ◽  
Current Flow ◽  
Discontinuity Point ◽  
Voltage Sweep ◽  
Current Voltage ◽  
Carrier Transport Property ◽  
Carrier Transport Properties

Abstract Carrier transport properties of ferroelectric Hf0.5Zr0.5O2 (HZO) thin films have been investigated on metal-ferroelectric-metal (MFM) capacitor in the first current flow of ferroelectric poling treatment. In current–voltage (I–V) measurement of MFM capacitor, a kink or discontinuity point of derivative in I–V characteristic appears, and after the cyclic voltage sweep this kink disappears. This phenomenon is different from the ferroelectric instabilities after several thousand or million voltage cycle applies reported as the wake-up and fatigue. From the analysis using Poole-Frenkel plot of I–V characteristics, it is suggested that irreversible trap generation by electric field apply occurs in poling treatment.

scholarly journals Verification of Redox Flow Batteries’ Functionality by Electrochemical Impedance Spectroscopy Tests

Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 58 ◽  
Author(s):  
Daniel Manschke ◽  
Thorsten Seipp ◽  
Sascha Berthold ◽  
K. Friedrich
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Comparison Method ◽  
Redox Flow Batteries ◽  
Current Voltage ◽  
Flow Batteries ◽  
Quantitative Statement ◽  
Characteristic Values ◽  
Eis Measurements

The state-of-the-art functionality test of classic redox-flow-stacks measures the current–voltage characteristic with the technical electrolyte. This research paper aims to simplify the validation of redox flow batteries’ functionality by conducting electrochemical impedance spectroscopy (EIS) on redox flow stacks. Since the electrolyte used in the batteries is usually toxic and aggressive, it would be a significant simplification to verify the functionality with an alternative, non-toxic fluid. EIS measurements on batteries with larger sized electrodes, multiple cells, and different fluids were performed. It was demonstrated that all impedances are repeatable, thereby validating this procedure as a qualification method for full-size and complex batteries with an alternative fluid. EIS measurements were able to detect deliberately manipulated cells. This research uses three different analysis methods for the acquired data to identify errors. The respective approaches are, firstly, (1) a comparison of the Nyquist plots; secondly, (2) a comparison of the Bode plots; and thirdly, (3) a comparison of the calculated characteristic values of the equivalent circuits. The analysis found that all methods are suitable to detect errors in the batteries. Nevertheless, the bode-plot comparison method proves to be especially advantageous, because it enables a quantitative statement.

One-Pot Electrodeposition of NiS Nanoparticles as an Efficient Electrode for Nonenzymatic H2O2 and Glucose Sensors

NANO ◽  
2019 ◽  
Vol 14 (01) ◽  
pp. 1950010
Author(s):  
Zhiheng Huang ◽  
Chunchuan Gu ◽  
Jiajun Wen ◽  
Langlang Zhu ◽  
Mingzhen Zhang ◽  
...  
Keyword(s):  
Metal Ion ◽  
Electrochemical Impedance ◽  
Glucose Sensors ◽  
Cyclic Voltammograms ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
One Pot ◽  
X Ray ◽  
First Time ◽  
Nis Nanoparticles

In this paper, a new and one-pot electrodeposition method was expanded for the preparation of NiS nanoparticles-based electrochemical biosensor using metal-ion complexes as a precursor. Thioacetamide was used to control the production rate of NiS nanoparticles for the first time. The proposed electrochemical sensor was characterized by energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FESEM), cyclic voltammograms (CV), and electrochemical impedance spectra (EIS). Experiment parameters were optimized. Under the optimized condition, the prepared NiS-based biosensor exhibited excellent electrocatalytic oxidation of H2O2 and glucose due to their small size. It provided fast and sensitive strategy for detecting H2O2 and glucose in the range of 1–5000 and 1–1000[Formula: see text][Formula: see text]M. The detection limit of 0.257 and 0.3[Formula: see text][Formula: see text]M was obtained for H2O2 and glucose. The mechanisms were also analyzed. The proposed biosensor exhibited excellent anti-interference and repeatability. Furthermore, it was applied in the actual sample analysis, such as human blood serum.

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