Journal articles: 'Faradic current'

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Shah, Anwar ul Haq Ali, Sadaf Zia, Gul Rahman, and Salma Bilal. "Performance Improvement of Gold Electrode towards Methanol Electrooxidation in Akaline Medium: Enhanced Current Density Achieved with Poly(aniline-co-2-hydroxyaniline) Coating at Low Overpotential." Polymers 14, no. 2 (January 13, 2022): 305. http://dx.doi.org/10.3390/polym14020305.

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Electronically conducting poly (aniline-co-2-hydroxyaniline) (PACHA), a copolymer of aniline and 2-hydroxyaniline (2HA), was electrochemically coated on gold substrate for methanol electrooxidation in alkaline media. The electrochemical behavior of PACHA coated gold electrode towards methanol electrooxidation was investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for application in an alkaline fuel cell. Methanol electrooxidation was observed at two different electrode potentials depending on the concentration of the base. At the PACHA coated gold electrode, the methanol oxidation peak was observed at lower overpotential (at 0.19 V) in a solution of high base concentration (1.8 M NaOH), which was 30 mV lower than the peak for the uncoated gold electrode. In addition, the Faradic current Imax obtained on the PACHA coated electrode (20 mA) was two times higher as compared to the Faradic current Imax of the un-modified gold electrode (10 mA). In solution of lower base concentration (0.06 M NaOH), the electrooxidation of methanol became sluggish on both electrodes, as indicated by peak shifting towards positive potential and with reduced faradaic current (at 0.74 V on PACHA coated electrode; Imax 10 mA). The electrooxidation of methanol at both lower and higher electrode potentials was analyzed mechanistically and discussed in light of the literature. EIS results were interpreted using Nyquist and Bode plots. The charge transfer resistance was decreased and pseudo-capacitive behavior changed to conductive behavior when external applied potential was increased from 0.1 V to 0.4 V.

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Baumung, Max, Florian Schönewald, Torben Erichsen, Cynthia A. Volkert, and Marcel Risch. "Influence of particle size on the apparent electrocatalytic activity of LiMn2O4 for oxygen evolution." Sustainable Energy & Fuels 3, no. 9 (2019): 2218–26. http://dx.doi.org/10.1039/c8se00551f.

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Abbas, Syed Asad, Seong-Hoon Kim, Hamza Saleem, Sung-Hee Ahn, and Kwang-Deog Jung. "Preparation of Metal Amalgam Electrodes and Their Selective Electrocatalytic CO2 Reduction for Formate Production." Catalysts 9, no. 4 (April 18, 2019): 367. http://dx.doi.org/10.3390/catal9040367.

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Electrochemical CO2 reduction to produce formate ions has studied for the sustainable carbon cycle. Mercury in the liquid state is known to be an active metallic component to selectively convert CO2 to formate ions, but it is not scalable to use as an electrode in electrochemical CO2 reduction. Therefore, scalable amalgam electrodes with different base metals are tested to produce formate by an electrochemical CO2 reduction. The amalgam electrodes are prepared by the electrodeposition of Hg on the pre-electrodeposited Pd, Au, Pt and Cu nanoparticles on the glassy carbon. The formate faradaic efficiency with the Pd, Au, Pt and Cu is lower than 25%, while the one with the respective metal amalgams is higher than 50%. Pd amalgam among the tested samples shows the highest formate faradic efficiency and current density. The formate faradaic efficiency is recorded 85% at −2.1 V vs SCE and the formate current density is −6.9 mA cm−2. It is concluded that Pd2Hg5 alloy on the Pd amalgam electrode is an active phase for formate production in the electrochemical CO2 reduction.

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Zhu, Qing Jun, Alin Cao, Ji Wen Song, and Sheng Li Chen. "Distribution of Stray Current in Buried Pipeline." Advanced Materials Research 433-440 (January 2012): 6579–82. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.6579.

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Electrochemical corrosion happens when stray currents leak out of buried pipeline. This will threaten the safety of pipeline operation and operators. The distribution of stray current was studied by simulation system. The results indicate that stray current intensities have the same distribution with potential gradient Esx which parallel to the metallic pipeline. The distribution curves of stray current show regular symmetry. The stray currents increase gradually along the buried metallic pipeline. It reaches maximum at the pipeline midpoint. The potential gradient Esy distribution curves in y-direction show a hyperbolic shape. For the exits of faradic electric field, stray current intensity is maximum in the beginning and it flows into the pipeline. It flow along the pipeline and parallel to the pipeline at middle. After that, the stray currents begin to flow back to cathode and the stray current intensity reaches maximum at the end of pipeline.

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Tatu, Laurent. "Edgar Adrian (1889–1977) and Shell Shock Electrotherapy: A Forgotten History?" European Neurology 79, no. 1-2 (2018): 106–7. http://dx.doi.org/10.1159/000486762.

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The English electrophysiologist Edgar Adrian (1889–1977) was the recipient of the Nobel Prize for physiology in 1932 for his research on the functions of neurons. During World War I, at Queen Square in London, he devised an intensive electrotherapeutic treatment for shell-shocked soldiers. The procedure, developed with Lewis Yealland (1884–1954), was similar to “torpillage,” the faradic psychotherapy used in France. Adrian and Yealland considered that the pain accompanying the use of faradic current was necessary for both therapeutic and disciplinary reasons, especially because of the suspicion of malingering. According to Adrian, this controversial electric treatment was only able to remove motor or sensitive symptoms. After the war, he finally admitted that war hysteria was a complex and difficult phenomenon.

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Kaplyanskiy, V. "C. Ludlow. The Use of Electricity in Midwifery (New-York Medical Journal, 1893: January 14). On the use of electricity in obstetrics." Journal of obstetrics and women's diseases 7, no. 5 (September 22, 2020): 428. http://dx.doi.org/10.17816/jowd75428.

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The author speaks only of faradic current, and examines its threefold action on a pregnant woman: 1) a calming effect on the general nervous system, 2) excitation of muscle contractions, 3) the ability of faradization to prevent and stop uterine bleeding. Pharadic current is very useful when chloroform, chloral-hydrate or morphine are more unacceptable, because of idiosyncrasy or weakness of the patient, as long as the maximum doses of these drugs are achieved without a proper effect, finally, when all is excreted.

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Bodamyali, T., J. M. Kanczler, B. Simon, D. R. Blake, and C. R. Stevens. "Effect of Faradic Products on Direct Current-Stimulated Calvarial Organ Culture Calcium Levels." Biochemical and Biophysical Research Communications 264, no. 3 (November 1999): 657–61. http://dx.doi.org/10.1006/bbrc.1999.1355.

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Morón, Carlos, Enrique Tremps, Alfonso Garcia, and Jose Andrés Somolinos. "Development of an Electrochemical Maltose Biosensor." Key Engineering Materials 495 (November 2011): 116–19. http://dx.doi.org/10.4028/www.scientific.net/kem.495.116.

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In this work, electrochemical maltose biosensors based on mutants of the maltose binding protein (MBP) are developed. A rutheniumIIcomplex (RuII), which is covalently attached to MBP, serves as an electrochemical reporter of MBP conformational changes. Biosensors were made through direct attachment of RuIIcomplex modified MBP to gold electrode surfaces. The responses of some individual mutants were evaluated using square wave voltammetry. A maltose-dependent change in Faradic current and capacitance was observed. It is therefore demonstrated that biosensors using generically this family of bacterial periplasmic binding proteins (bPBP) can be made lending themselves to facile biorecognition element preparation and low cost electrochemical transduction.

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Abdelatief, Emad Eldin Mohamed. "Effect of Transcutaneous Electrical Nerve Stimulation and Faradic Current Stimulation on the Recovery of Bell's Palsy." International Journal of Human Movement and Sports Sciences 8, no. 6 (December 2020): 369–79. http://dx.doi.org/10.13189/saj.2020.080608.

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جبر, Nasma Adnan, Aiyah Sabah نوري, Emad Eyad حسين, and Maha Adnan جبر. "A Review of Treatment Methods Using Electrical Stimulation." Journal of medical and pharmaceutical sciences 6, no. 6 (December 29, 2022): 1–16. http://dx.doi.org/10.26389/ajsrp.b040922.

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This article deals with a theoretical study of methods of electrical stimulation therapy which is one of the physical therapy used to treat pain and increase the strength of the weak muscle where the treatment is done by connecting electrodes to the patient which in turn deliver electrical impulses through nerve paths at specific intervals. Also, the relationship between methods of electrical stimulation and types of electric current has been shown in this review, Stimulation methods were divided according to the type of current used where continuous current is used in the case of galvanic with high frequency and low current. Methods (Trabert, Leduc, Faradic, H-wave, Micro-current) use the pulse current with a frequency not exceeding 1000 Hz, while methods like Transcutaneous Electrical Nerve Stimulation (TENS), Four-pole interfering, Two-pole interfering, Isoplaner interfering, Neuromuscular, dipole interfering, diadynamic use alternating current with a frequency between (3600 Hz - 10000 Hz) and the value of the current is between (50 mA - 140 mA). The most important effect or use of electrical stimulation is to reduce pain (Analgesic effect), as well as, 2-pole and 4-pole interference effect on myorelaxation and spasmolytic. Finally, there are many studies that show that there are no long-term side effects of electrical stimulation, only some temporary effects resulting from the misuse of electrodes for the stimulation device or resulting from the use of high currents.

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Sui, Xiao Hong, Fei Tan, and Qiu Shi Ren. "Electrical Characteristics of a Stimulating Microelectrode-Electrolyte Interface." Key Engineering Materials 483 (June 2011): 690–93. http://dx.doi.org/10.4028/www.scientific.net/kem.483.690.

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The electrochemical stability of the implantable microelectrode array is one of the most important considerations for effective neural stimulation. Electrical characteristics of a polyimide-based platinum microelectrode-electrolyte interface were presented in this paper, which could help determine some stimulus parameters in neural restoration applications. The novel 16-channel Φ-200 μm polyimide-based platinum thin-film flexible microelectrode array was micro-fabricated and an appropriate circuit model of the electrode-electrolyte interface was adopted with three different components of series capacitance Cs, series resistance Rs and Faradic resistance Rf. By using sinusoidal testing signals, the respective changing relationships between the former two components and modulus of impedance Z vs. applied current density were tested in vitro at 37.8°C. The tested results showed that the magnitude of Cs and Rs maintained respective constant values at the low stimulating current density, while with current density gradually increasing, Cs increased and Rs decreased sharply. The tested electrochemical impedance in vitro decreased with the increasing frequency.

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Srirussamee, Kasama, Ruikang Xue, Sahba Mobini, Nigel J. Cassidy, and Sarah H. Cartmell. "Changes in the extracellular microenvironment and osteogenic responses of mesenchymal stem/stromal cells induced by in vitro direct electrical stimulation." Journal of Tissue Engineering 12 (January 2021): 204173142097414. http://dx.doi.org/10.1177/2041731420974147.

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Electrical stimulation (ES) has potential to be an effective tool for bone injury treatment in clinics. However, the therapeutic mechanism associated with ES is still being discussed. This study aims to investigate the initial mechanism of action by characterising the physical and chemical changes in the extracellular environment during ES and correlate them with the responses of mesenchymal stem/stromal cells (MSCs). Computational modelling was used to estimate the electrical potentials relative to the cathode and the current density across the cell monolayer. We showed expression of phosphorylated ERK1/2, c-FOS, c-JUN, and SPP1 mRNAs, as well as the increased metabolic activities of MSCs at different time points. Moreover, the average of 2.5 μM of H2O2 and 34 μg/L of dissolved Pt were measured from the electrically stimulated media (ES media), which also corresponded with the increases in SPP1 mRNA expression and cell metabolic activities. The addition of sodium pyruvate to the ES media as an antioxidant did not alter the SPP1 mRNA expression, but eliminated an increase in cell metabolic activities induced by ES media treatment. These findings suggest that H2O2 was influencing cell metabolic activity, whereas SPP1 mRNA expression was regulated by other faradic by-products. This study reveals how different electrical stimulation regime alters cellular regenerative responses and the roles of faradic by-products, that might be used as a physical tool to guide and control cell behaviour.

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Geddes, L. A., and R. Roeder. "Measurement of the Direct-Current (Faradic) Resistance of the Electrode-Electrolyte Interface for Commonly Used Electrode Materials." Annals of Biomedical Engineering 29, no. 2 (February 2001): 181–86. http://dx.doi.org/10.1114/1.1349699.

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Shamsah, Sami M. Ibn. "Electrochemical Performance of Cupric Oxide Loaded Carbon Nanotubes as Electrode Material for CO2 Reduction." Journal of New Materials for Electrochemical Systems 24, no. 1 (March 31, 2021): 9–13. http://dx.doi.org/10.14447/jnmes.v24i1.a02.

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This study is conducted to explore the effective and stable electrode materials for electrochemical reduction of CO2. The different compositions (3 - 8%) CuO-supported CNT samples were prepared by a traditional sol-gel method, and the prepared materials were characterized by TGA, SEM, TEM, FTIR and XRD. The characterization results confirmed the uniform impregnation of CuO on the defects of the CNT's, which improved the utilization of meso and microporous distribution in the prepared electrocatalyst. The high surface area and stability of CuO- CNTs allowed dual conduction of electron and intermediate species with high current density at minimum energy supplied. Linear sweep voltammetry and Chronoamperometry were used to measure the electrode's current density and stability, respectively, and 8 % CuO- CNT was found most stable and progressive composition to reduce the CO2 efficiently. Further, the liquid products were analyzed using the gas chromatography, and 20 % faradic efficiency of methane was measured.

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Usman, Muhammad, Muhammad Humayun, Mustapha D. Garba, Latif Ullah, Zonish Zeb, Aasif Helal, Munzir H. Suliman, et al. "Electrochemical Reduction of CO2: A Review of Cobalt Based Catalysts for Carbon Dioxide Conversion to Fuels." Nanomaterials 11, no. 8 (August 9, 2021): 2029. http://dx.doi.org/10.3390/nano11082029.

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Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach to curbing harmful emissions contributing to global warming. However, several challenges hinder the commercialization of this technology, including high overpotentials, electrode instability, and low Faradic efficiencies of desirable products. Several materials have been developed to overcome these challenges. This mini-review discusses the recent performance of various cobalt (Co) electrocatalysts, including Co-single atom, Co-multi metals, Co-complexes, Co-based metal–organic frameworks (MOFs), Co-based covalent organic frameworks (COFs), Co-nitrides, and Co-oxides. These materials are reviewed with respect to their stability of facilitating CO2 conversion to valuable products, and a summary of the current literature is highlighted, along with future perspectives for the development of efficient CO2RR.

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Karimi-Maleh, Hassan, Fatemeh Karimi, Morteza Rezapour, Majede Bijad, Mohammad Farsi, Aliasghar Beheshti, and Seyed-Ahmad Shahidi. "Carbon Paste Modified Electrode as Powerful Sensor Approach Determination of Food Contaminants, Drug Ingredients, and Environmental Pollutants: A Review." Current Analytical Chemistry 15, no. 4 (July 3, 2019): 410–22. http://dx.doi.org/10.2174/1573411014666181026100037.

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Background: Application of electrochemical sensors for analysis of food, biological and water polluting compounds helps to speed up their analysis in the real samples. Electrochemical sensors with low cost, fast response and portable ability are a better choice compared to traditional methods for analysis of electro-active compounds such as HPLC. Therefore, in recent years, many analytical scientists have suggested this type of analytical method for analysis of food, biological compounds and water pollutants. Objective: Due to low cost, easy modification and low non-faradic current, the carbon paste electrode is a suitable choice as a working electrode in the electrochemical and especially voltammetric analysis. On the other hand, modification of carbon paste electrode can improve the quality of the sensor for the analysis of electroactive compounds at nanomolar level.

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Potturi, Gowrishankar, A. N. Sundaresan, J. Mahendran, P. D. Karthikeyan, and V. Krishna Reddy. "Effect of Dexamethasone Iontophoresis Combined with Strong Surged Faradic Current on Piriformis Syndrome -A Simple Randomized Control Clinical Trail." Indian Journal of Physiotherapy and Occupational Therapy - An International Journal 8, no. 4 (2014): 265. http://dx.doi.org/10.5958/0973-5674.2014.00049.5.

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Oliver-Tolentino, Miguel A., Elmer Jiménez-Álvarez, María De Jesús Martínez-Ortiz, Efrén García-Báez, M. Olivia Franco-Hernández, and Ariel Guzmán-Vargas. "Effective Electro-Fenton Degradation of Reactive Black 5 Dye using Modified Electrode with Cu-Zeolites." Journal of New Materials for Electrochemical Systems 17, no. 2 (April 15, 2014): 071–75. http://dx.doi.org/10.14447/jnmes.v17i2.426.

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The electrocatalytic production of hydroxyl radical (HO•) on the surface of zeolite modified electrode (ME) employing Cu-Zeolites (ZSM5 and β) with different theoretical ionic exchange (15 and 100%) was investigated (ME/Cu-Zeolites). The i-E characteristic of ME/Cu-ZSM-5 presented the faradic process associated to redox couple Cu2+/Cu+. On the other hand, voltammetric studies showed that in presence of H2O2, the cathodic peak current of ME/Cu-Zeolites increases followed by a decrease in the corresponding anodic current. This suggested that hydroxyl radical was produced by a cooperative effect of the acidic properties of zeolite and copper that acts as a redox mediator on the electrode surface via an electrocatalytic mechanism. Experiments of degradation using azo dye Reactive Black 5 as probe molecule exhibited that the concentration of azo dye decreased in the time, this confirms the formation of hydroxyl radical on the surface of modified electrode; kinetics parameters demonstrated that the ME/Cu- β with 15% of ionic exchange presented the highest catalytic activity.

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Nogalska, Adrianna, Andreu Bonet Navarro, and Ricard Garcia-Valls. "MEA Preparation for Direct Formate/Formic Acid Fuel Cell—Comparison of Palladium Black and Palladium Supported on Activated Carbon Performance on Power Generation in Passive Fuel Cell." Membranes 10, no. 11 (November 19, 2020): 355. http://dx.doi.org/10.3390/membranes10110355.

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Membrane electrode assemblies (MEAs) with palladium catalysts were successfully prepared by using a home-made manual pressing system with Nafion glue application that contributed to a decrease of additional energy consumption. The catalyst coated membranes were prepared with supported palladium on activated carbon (PdC) and unsupported palladium black (PdB) for comparison. The performance of passive, air breathing, functioning under ambient conditions and with low concentration (1 M) formate/formic acid fuel cell was evaluated. Based on polarization curves, the best result was obtained with carbon supported catalyst and HCOOK fuel, achieving 21.01 mW/mgPd. Still, constant current discharge with PdC showed an energy generation efficiency of 14% with HCOOH over 3% with HCOOK caused by lower potassium ion conductivity and its permeability through the proton exchange membrane. The faradic efficiency of conversion in the cell is equal to the overall energy efficiency and makes the cell self-sufficient.

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Wang, Haiyan, Yuzhuo Chen, Ruxue Fan, Jiadong Chen, Zhe Wang, Shanjun Mao, and Yong Wang. "Selective Electrochemical Reduction of Nitrogen to Ammonia by Adjusting the Three-Phase Interface." Research 2019 (November 30, 2019): 1–12. http://dx.doi.org/10.34133/2019/1401209.

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The electrochemical nitrogen reduction reaction (NRR) provides a sustainable and alternative avenue to the Haber-Bosch process for ammonia (NH3) synthesis. Despite the great efforts made on catalysts and electrolytes, unfortunately, current NRR suffers from low selectivity due to the overwhelming competition with the hydrogen evolution reaction (HER). Here, we present an adjusted three-phase interface to enhance nitrogen (N2) coverage on a catalyst surface and achieve a record-high Faradic efficiency (FE) up to 97% in aqueous solution. The almost entirely suppressed HER process combined with the enhanced NRR activity, benefiting from the efficient three-interface contact line, is responsible for the excellent selectivity toward NH3, as evidenced by the theoretical and experimental results. Our strategy also demonstrates the applicability to other catalysts that feature strong H adsorption ability, to boost the FE for NH3 synthesis above 90% and to improve the NRR activity by engineering the catalysts.

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Moore, L. C., C. Clausen, E. F. Bowden, and A. Birzgalis. "In vivo measurement of tubular fluid ferrocyanide with carbon-fiber microelectrodes." American Journal of Physiology-Renal Physiology 252, no. 6 (June 1, 1987): F1158—F1166. http://dx.doi.org/10.1152/ajprenal.1987.252.6.f1158.

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Techniques to construct carbon-fiber microelectrodes and to measure ferrocyanide ion concentration in single nephrons are described. The measurement involves polarizing an inert carbon-fiber microelectrode 500 mV positive with respect to a Ag-AgCl reference, while measuring the faradic current produced by the oxidation of ferrocyanide. A carbon fiber (5-7 micron diam) is heat sealed into a glass micropipette that is then sharpened, silanized, and electrochemically pretreated to minimize electrode degradation by protein. Circuit diagrams for an inexpensive voltage clamp-current monitor and a data sampling device are presented. The electrodes show a linear response to changes in ferrocyanide concentration in large and very small (20 nl) volumes in vitro. The electrodes were used in an electrochemical microassay to determine tubular fluid-to-plasma ferrocyanide concentration ratios and nephron filtration rates with proximal micropuncture samples. The results show excellent agreement with paired determinations using [3H]inulin. In vivo proximal tubule perfusion experiments show a rapid linear response to changes in tubular fluid ferrocyanide concentration. These electrodes permit rapid quantitative measurements of ferrocyanide concentration and water transport in the proximal tubule and may be useful in other biological systems.

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Espinosa, José R., Marisol Galván, Arturo S. Quiñones, Jorge L. Ayala, Verónica Ávila, and Sergio M. Durón. "Electrochemical Resistive DNA Biosensor for the Detection of HPV Type 16." Molecules 26, no. 11 (June 5, 2021): 3436. http://dx.doi.org/10.3390/molecules26113436.

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In this work, a low-cost and rapid electrochemical resistive DNA biosensor based on the current relaxation method is described. A DNA probe, complementary to the specific human papillomavirus type 16 (HPV-16) sequence, was immobilized onto a screen-printed gold electrode. DNA hybridization was detected by applying a potential step of 30 mV to the system, composed of an external capacitor and the modified electrode DNA/gold, for 750 µs and then relaxed back to the OCP, at which point the voltage and current discharging curves are registered for 25 ms. From the discharging curves, the potential and current relaxation were evaluated, and by using Ohm’s law, the charge transfer resistance through the DNA-modified electrode was calculated. The presence of a complementary sequence was detected by the change in resistance when the ssDNA is transformed in dsDNA due to the hybridization event. The target DNA concentration was detected in the range of 5 to 20 nM. The results showed a good fit to the regression equation ΔRtotal(Ω)=2.99 × [DNA]+81.55, and a detection limit of 2.39 nM was obtained. As the sensing approach uses a direct current, the electronic architecture of the biosensor is simple and allows for the separation of faradic and nonfaradaic contributions. The simple electrochemical resistive biosensor reported here is a good candidate for the point-of-care diagnosis of HPV at a low cost and in a short detection time.

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Ma, Hedi, Warren Brown, Shuang Chen, Sarah A. Ake, and Gangli Wang. "Kinetics of the Near Infrared Electrochemiluminescence from Metal Nanoclusters on Surface and in Solution." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 126528. http://dx.doi.org/10.1149/1945-7111/ac4457.

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The electronics structures of some metal nanoclusters enable strong photoluminescence in the near infrared spectrum range. Activation of the luminescence via electrode reactions, rather than light source, i.e., electrochemiluminescence (ECL), has received growing interests due to the various potential benefits, but has been mostly limited to steady-state behaviors such as overall emission intensity and materials optimizations. Here, the ECL kinetics in representative experiments where nanoclusters as luminophores are either immobilized on the surface or free diffusing in solution were investigated based on classic theory. An analytical equation derived under a sequential mass transport limit regime quantitates the experimental ECL kinetics features in a wide range of conditions. Deconvolution of non-faradic charging current from redox current provides the threshold in time ranges for the analysis of ECL kinetics. The ECL kinetics profiles suggest that bimolecular or pseudo first order reactions limit the ECL generation immediately following the establishment of the applied potentials, while later ECL generation is governed by diffusion or mass transport displaying a Cottrell type decay over inverse square root time. Physical meanings of key parameters as defined in classic theorem are discussed in representative experimental systems for appropriate quantitation and evaluation of ECLs properties from different materials systems.

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Li, Sanxiu, Yufei Kang, Chenyang Mo, Yage Peng, Haijun Ma, and Juan Peng. "Nitrogen-Doped Bismuth Nanosheet as an Efficient Electrocatalyst to CO2 Reduction for Production of Formate." International Journal of Molecular Sciences 23, no. 22 (November 21, 2022): 14485. http://dx.doi.org/10.3390/ijms232214485.

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Electrochemical CO2 reduction (CO2RR) to produce high value-added chemicals or fuels is a promising technology to address the greenhouse effect and energy challenges. Formate is a desirable product of CO2RR with great economic value. Here, nitrogen-doped bismuth nanosheets (N-BiNSs) were prepared by a facile one-step method. The N-BiNSs were used as efficient electrocatalysts for CO2RR with selective formate production. The N-BiNSs exhibited a high formate Faradic efficiency (FEformate) of 95.25% at −0.95 V (vs. RHE) with a stable current density of 33.63 mA cm−2 in 0.5 M KHCO3. Moreover, the N-BiNSs for CO2RR yielded a large current density (300 mA cm−2) for formate production in a flow-cell measurement, achieving the commercial requirement. The FEformate of 90% can maintain stability for 14 h of electrolysis. Nitrogen doping could induce charge transfer from the N atom to the Bi atom, thus modulating the electronic structure of N-Bi nanosheets. DFT results demonstrated the N-BiNSs reduced the adsorption energy of the *OCHO intermediate and promoted the mass transfer of charges, thereby improving the CO2RR with high FEformate. This study provides a valuable strategy to enhance the catalytic performance of bismuth-based catalysts for CO2RR by using a nitrogen-doping strategy.

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Suliman, Munzir H., Zain H. Yamani, and Muhammad Usman. "Electrochemical Reduction of CO2 to C1 and C2 Liquid Products on Copper-Decorated Nitrogen-Doped Carbon Nanosheets." Nanomaterials 13, no. 1 (December 22, 2022): 47. http://dx.doi.org/10.3390/nano13010047.

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Due to the significant rise in atmospheric carbon dioxide (CO2) concentration and its detrimental environmental effects, the electrochemical CO2 conversion to valuable liquid products has received great interest. In this work, the copper-melamine complex was used to synthesize copper-based electrocatalysts comprising copper nanoparticles decorating thin layers of nitrogen-doped carbon nanosheets (Cu/NC). The as-prepared electrocatalysts were characterized by XRD, SEM, EDX, and TEM and investigated in the electrochemical CO2 reduction reaction (ECO2RR) to useful liquid products. The electrochemical CO2 reduction reaction was carried out in two compartments of an electrochemical H-Cell, using 0.5 M potassium bicarbonate (KHCO3) as an electrolyte; nuclear magnetic resonance (1H NMR) was used to analyze and quantify the liquid products. The electrode prepared at 700 °C (Cu/NC-700) exhibited the best dispersion for the copper nanoparticles on the carbon nanosheets (compared to Cu/NC-600 & Cu/NC-800), highest current density, highest electrochemical surface area, highest electrical conductivity, and excellent stability and faradic efficiency (FE) towards overall liquid products of 56.9% for formate and acetate at the potential of −0.8V vs. Reversible Hydrogen Electrode (RHE).

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Yu, Yan, Na Zhong, Jinhui Fang, Shasha Tang, Xincheng Ye, Zhiqiao He, and Shuang Song. "Comparative Study between Pristine Ag and Ag Foam for Electrochemical Synthesis of Syngas with Carbon Dioxide and Water." Catalysts 9, no. 1 (January 8, 2019): 57. http://dx.doi.org/10.3390/catal9010057.

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The electrosynthesis of syngas (H2 + CO) from CO2 and H2O can reduce greenhouse gas emissions and address the energy crisis. In the present work, silver (Ag) foam was employed as a catalytic electrode for the electrochemical reduction of CO2 in aqueous solution to design different syngas ratios (H2:CO). In addition to H2 and CO, a small amount of formic acid was found in the liquid phase. By contrast, the planar polycrystalline Ag yields CO, formic acid, methane and methanol as the carbon-containing products. During the potential-controlled electrolysis, the Ag foam displayed a relatively higher activity and selectivity in the electroreduction of aqueous CO2 to CO compared with its smooth surface counterpart, as evidenced by the lower onset potential, higher partial current density and Faradic efficiency at the same bias voltage. Moreover, the electrode remained stable after three successive cycles. Based on the characterization using X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, potential step determination and density functional theory calculations, superior performance was credited to the three-dimensional structure of Ag foam constructed with coral-like Ag particles, in which the numerous edge sites are beneficial for the stabilization of the surface adsorbed COOH species and the exposed {111} facets favor the desorption of adsorbed CO species.

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Yoshimi, Yasuo, Daichi Oino, Hirofumi Ohira, Hitoshi Muguruma, Ewa Moczko, and Sergey Piletsky. "Size of Heparin-Imprinted Nanoparticles Reflects the Matched Interactions with the Target Molecule." Sensors 19, no. 10 (May 27, 2019): 2415. http://dx.doi.org/10.3390/s19102415.

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It has been shown that the faradic current at an electrode grafted with molecularly imprinted polymer (MIP) is sensitive to the specific target molecule used as the template. This phenomenon is applicable to sensors with very high selectivity, but the sensing mechanism is still a black box. We investigated the size sensitivity of nanoparticles of molecularly imprinted polymers (MIP-NPs) to a specific interaction for determination of the mechanism of the gate effect and its feasibility for new applications. Nanoparticles of poly(methacryloxy ethyl trimethylammonium chloride-co-acrylamide-co-methylenebisacrylamide) imprinted with heparin immobilized on glass beads were synthesized. The diameter of the MIP-NPs of heparin was increased by the presence of the heparin template but was insensitive to chondroitin sulfate C (CSC), the analogue of heparin. The high selectivity of the MIP-NPs was consistent with the selectivity of electrodes grafted with a heparin-imprinted polymer in our previous studies. The quartz crystal microbalance probes immobilizing heparin or CSC were sensitive to MIP-NPs, which indicates that the binding ability of MIP-NP does not discriminate between the template and other glycosaminoglycans. These results indicate that the size of the MIP-NP is sensitive to the matched binding with the template through the imprinted cavity.

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Espinosa, Galván, Quiñones, Ayala, and Durón. "DNA Biosensor Based on Double-Layer Discharge for the Detection of HPV Type 16." Sensors 19, no. 18 (September 13, 2019): 3956. http://dx.doi.org/10.3390/s19183956.

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DNA electrochemical biosensors represent a feasible alternative for the diagnosis of different pathologies. In this work, the development of an electrochemical method for Human Papillomavirus-16 (HPV-16) sensing is reported based on potential relaxation measurements related to the discharge of a complex double layer of a DNA-modified gold electrode. The method used allows us to propose an equivalent circuit (EC) for a DNA/Au electrode, which was corroborated by electrochemical impedance spectroscopy (EIS) measurement. This model differs from the Randles circuit that is commonly used in double-layer simulations. The change in the potential relaxation and associated charge transfer resistance were used for sensing the DNA hybridization by using the redox pair Fe(CN)64-/Fe(CN)63+ as an electrochemical indicator. In order to determinate only the potential relaxation of the composed double layer, the faradic and double-layer current contributions were separated using a rectifier diode arrangement. A detection limit of 0.38 nM was obtained for the target HPV-16 DNA sequences. The biosensor showed a qualitative discrimination between a single-base mismatched sequence and the fully complementary HPV-16 DNA target. The results indicate that the discharge of the double-layer detection method can be used to develop an HPV DNA biosensor.

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Singh, Abhay Narayan, Rakesh Mondal, Chandana Rath, and Preetam Singh. "Electrochemical Performance of Delafossite, AgFeO₂: A Pseudo-Capacitive Electrode in Neutral Aqueous Na₂SO₄ Electrolyte." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 120512. http://dx.doi.org/10.1149/1945-7111/ac3c23.

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Layered delafossite AgFeO2 with open channel structure is envisaged as a pseudo capacitor electrode using Fe2+/Fe3+ redox couple. A simple co-precipitation method was employed for the phase formation of delafossite AgFeO2 resulting in a mixture of 2H and 3R-phase. Phase tuning of 2H phase was done by controlling the calcination conditions and characterizing by powder XRD, FT-IR, and Raman methods. 2H AgFeO2 was used to synthesize as a majority phase because it have the larger inter layer spacing than 3R phase shown. HRTEM study confirms the formation 2H phase in majority. All of the synthesized samples exhibit predominantly faradic battery-type redox behavior along with surface charge storage. Flower like microarchitectures of AgFeO2 show outstanding electrochemical performance with high specific capacity of 110.4 F g−1 at 1 A g−1 current density, that retained up to 89% after 2000th times charge/discharge in 1 M Na2SO4 electrolyte. In an asymmetric device mode, AFO-400//AC full cell exhibits superior electrochemical performance by delivering high energy density (33.5 Wh kg−1) and high power density (454.3 W kg−1) with excellent cycling stability (86% retention after 2000th cycles). The results clearly demonstrate that the synthesized delafossite AgFeO2 containing mixture of 2H and 3R-phases have remarkable potential to be used as a negative electrode material for supercapacitor and other energy storage technologies.

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Passalacqua, Rosalba, Salvatore Abate, Federica De Luca, Siglinda Perathoner, and Gabriele Centi. "Graphitic Layered Structures Enhancing TiNT Catalyst Photo-Electrochemical Behaviour." Coatings 13, no. 2 (February 4, 2023): 358. http://dx.doi.org/10.3390/coatings13020358.

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The increasing knowledge in nanoscience and materials technology promoted the development of advanced materials with enhanced and unusual properties suitable for sustainable applications ranging from energy to environmental purposes. Here are presented some results from our current investigations on composite semiconducting materials. The investigated composites have been prepared from different nitrogen precursors and thin films of TiO2 nanotubes. The synergy between hetero-structures based on graphitic-C3N4 and thin films of titania nanotubes obtained by anodisation was studied. The composites have been characterised with several complementary techniques to evidence the relation between photo-behaviour and the composition of the samples. This study allows new insights into the nature of the specific enhanced properties due to this synergy among the two compounds. The g-C3N4/TiNT heterojunctions showed enhanced photo-electrochemical properties observed from the photocurrent measurements. The as-prepared composites have been investigated as cathode materials in the electrocatalytic reduction of oxalic acid (OX), evidencing the capability of tuning the reaction toward glycolic acid with respect to the pristine TiNT array. The observed Faradic efficiency (FE) for the composites follows the trend: TiNT-U6 > TiNT-M6 > TiNT-MU18. TiNT-U6 shows the best performances (FEGC = 63.7%; FEGO = 15.5%; OX conversion = 61. 4%) after 2 h of reaction. The improved photo-electrochemical properties make these materials suitable for H2 production, solar-light-driven water splitting, and CO2 reduction applications.

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Bekhterev, V. M. "On the location of the motor centers of the cerebral cortex in a person according to the results of irritation by their faradic current during cerebral operations." Neurology Bulletin VII, no. 3 (November 25, 2020): 1–5. http://dx.doi.org/10.17816/nb50094.

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The question of the location of the motor centers of the cerebral cortex in a human until late time can be clarified only on the basis of the observation with the destruction of certain parts of the motor areas and those cases in which the pathological nest served as a source of irritation and led to local seizures. Valuable as these observations are, they did not often make it possible to find out with such strict accuracy the position and boundaries of the motor centers of the cortex in humans, as they make it possible to perform experiments on animals. Only in a later time, along with the development of brain surgery, during the production of Horsley's operations in cases of epilepsy, did it become possible to study the motor centers of the human cerebral cortex with the help of an electric current, that is, in the same way as we do it animals.

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Zouaoui, Fares, Saliha Bourouina-Bacha, Mustapha Bourouina, Nadia Zine, Abdelhamid Errachid, and Nicole Jaffrezic-Renault. "Mathematical Modelling of Glyphosate Molecularly Imprinted Polymer-Based Microsensor with Multiple Phenomena." Molecules 27, no. 2 (January 13, 2022): 493. http://dx.doi.org/10.3390/molecules27020493.

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The massive and careless use of glyphosate (GLY) in agricultural production raises many questions regarding environmental pollution and health risks, it is then important to develop simple methods to detect it. Electrochemical impedance spectroscopy (EIS) is an effective analytical tool for characterizing properties at the electrode/electrolyte interface. It is useful as an analytical procedure, but it can also help in the interpretation of the involved fundamental electrochemical and electronic processes. In this study, the impedance data obtained experimentally for a microsensor based on molecularly imprinted chitosan graft on 4-aminophenylacetic acid for the detection of glyphosate was analyzed using an exact mathematical model based on physical theories. The procedure for modeling experimental responses is well explained. The analysis of the observed impedance response leads to estimations of the microscopic parameters linked to the faradic and capacitive current. The interaction of glyphosate molecules with the imprinted sites of the CS-MIPs film is observed in the high frequency range. The relative variation of the charge transfer resistance is proportional to the log of the concentration of glyphosate. The capacitance decreases as the concentration of glyphosate increases, which is explained by the discharging of the charged imprinted sites when the glyphosate molecule interacts with the imprinted sites through electrostatic interactions. The phenomenon of adsorption of the ions in the CMA film is observed in the low frequency range, this phenomenon being balanced by the electrostatic interaction of glyphosate with the imprinted sites in the CS-MIPs film.

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Yang, Xianghua, Shiqing Wu, Qian Zhang, Songbai Qiu, Yuan Wang, Junjun Tan, Liang Ma, Tiejun Wang, and Yongde Xia. "Surface Structure Engineering of PdAg Alloys with Boosted CO2 Electrochemical Reduction Performance." Nanomaterials 12, no. 21 (November 1, 2022): 3860. http://dx.doi.org/10.3390/nano12213860.

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Converting carbon dioxide into high-value-added formic acid as a basic raw material for the chemical industry via an electrochemical process under ambient conditions not only alleviates greenhouse gas effects but also contributes to effective carbon cycles. Unfortunately, the most commonly used Pd-based catalysts can be easily poisoned by the in situ formed minor byproduct CO during the carbon dioxide reduction reaction (CRR) process. Herein, we report a facile method to synthesize highly uniformed PdAg alloys with tunable morphologies and electrocatalytic performance via a simple liquid synthesis approach. By tuning the molar ratio of the Ag+ and Pd2+ precursors, the morphologies, composition, and electrocatalytic activities of the obtained materials were well-regulated, which was characterized by TEM, XPS, XRD, as well as electrocatalytic measurements. The CRR results showed that the as-obtained Pd3Ag exhibited the highest performance among the five samples, with a faradic efficient (FE) of 96% for formic acid at −0.2 V (vs. reference hydrogen electrode (RHE)) and superior stability without current density decrease. The enhanced ability to adsorb and activate CO2 molecules, higher resistance to CO, and a faster electronic transfer speed resulting from the alloyed PdAg nanostructure worked together to make great contributions to the improvement of the CRR performance. These findings may provide a new feasible route toward the rational design and synthesis of alloy catalysts with high stability and selectivity for clean energy storage and conversion in the future.

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Kono, Daiki, Yuya Harada, Dai Xinjie, and Tsukasa Yoshida. "Electropolymerization of Neutral Red." ECS Meeting Abstracts MA2022-02, no. 64 (October 9, 2022): 2361. http://dx.doi.org/10.1149/ma2022-02642361mtgabs.

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Hydrogen bonding conductive polymers have attracted attention as metal-free electrocatalysts for energy conversion (1)(2). Neutral red (NR), a pH indicator in the family of phenazine dyes, can be polymerized into poly-NR (PNR) just like aniline (ANI) does into poly-ANI (PANI). Due to the presence of hydrogen bonding N atom, PNR has been found to act as a good catalyst for hydrogen evolution reaaction (HER) (3). Although electropolymerization to achieve these polymer films is believed to take off by oxidation of the monomers into their respective radicals, potential sweep and cycling in a wide potential range are almost always employed, in other words, the films are obtained in the course of cyclic voltammetry (CV) in the monomer solutions. A clear benefit of such a method is to facilitate monitoring of the film growth, as the electrodeposited polymers often show a redox behavior. However, it is not easy to elucidate electrochemical stoichiometry and its Faradic efficiency by charge integration from the CVs during the film growth. If the electrochemical oxidation of the monomers is the only important process, potentiostatic electrolysis and chronoamperometric (CA) monitoring should work as well and be beneficial to the understanding of the reaction mechanism. However, to our knowledge, no such studies have been reported so far. In this study, several different protocols of electrolysis have been tested and compared for electropolymerization of NR, i.e., potential sweep/cycling (CV), potentiostatic electrolysis (CA), potential stepping pulsed electrolysis (PP), with variation of conditions and also by their combinations. While reddish black thin films of PNR were nicely obtained by the standard CV method up to +1.2 V vs. Ag/AgCl to oxidize NR and down to -0.2 V to observe reduction of NR as well as electrodeposited PNR in acidic aqueous solutions of NR + H2SO4, the CA method to apply a constant potential of +1.05 V, sufficiently positive to promote oxidation of NR resulted in in a significant slowdown of PNR growth. The CA method, however, did result in a formation of PNR. Comparison of anodic charge for monomer oxidation both in the CV and CA methods with the optical density (O.D.) of the resulting PNR proved proportionality of O.D. to charge with the same O.D./charge ratios, thus the same Faradic efficiencies. In fact, CA showed a drastic decrease of current down to a rather small steady-state value. This was not caused by depletion of NR at the vicinity of the electrode, but by slowdown of charge transfer kinetics, as the introduction of forced convection by employing a rotating disk electrode (RDE) did not result in any enhancement of current. On the other hand, the anodic peak current only slightly decreased over multiple potential cycling in the CV method. The peak current was approximately linearly proportional to the square root of the scan rate, so that fast charge transfer to hit the diffusion limit of NR was achieved in the CV method. The cause of the difference of charge transfer kinetics was further studied. Anodic growth of PNR naturally results in doping of anions, in this case sulfate, to stabilize polarons to achieve conductivity of PNR. Careful observation of CVs found presence of a couple of small peaks which correspond to doping / dedoping at around +0.5 V. Electrodeposition of PNR by the CV method with variation of negative end potential revealed the importance of dedoping of sulfate to refresh the surface of PNR to be favorable to the oxidation of NR, not the reduction /re-oxidation of the existing PNR. Thus, the PP method to switch the potential between that for the oxidation of NR monomer and the one for dedoping of sulfate from PNR (not the reduction of PNR) achieved the fastest growth of PNR. The above-documented understanding of the electropolymerization of NR will be explained in a quantitative manner along with the experimental data. It is also interesting to mention the difference of the absorption spectra of the PNR films between those obtained by CV and CA methods, indicating their differences in the electronic structure to let us anticipate their differences in the HER electrocatalysis. Reference: Coskun H. al.，Adv. Mater. 32, 25, e1902177 (2020). Coskun H. et. al.， Sustainable Syst. 5, 25, 2000176 (2021). Yuya H al.，The ECS spring meeting abstract 1A17 (2021).

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Fernando, Niranjala, Hugo Veldhuizen, Atsushi Nagai, Sybrand van der Zwaag, and Amor Abdelkader. "Layer-by-Layer Electrode Fabrication for Improved Performance of Porous Polyimide-Based Supercapacitors." Materials 15, no. 1 (December 21, 2021): 4. http://dx.doi.org/10.3390/ma15010004.

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Nanoporous polymers are becoming increasingly interesting materials for electrochemical applications, as their large surface areas with redox-active sites allow efficient adsorption and diffusion of ions. However, their limited electrical conductivity remains a major obstacle in practical applications. The conventional approach that alleviates this problem is the hybridisation of the polymer with carbon-based additives, but this directly prevents the utilisation of the maximum capacity of the polymers. Here, we report a layer-by-layer fabrication technique where we separated the active (porous polymer, top) layer and the conductive (carbon, bottom) layer and used these “layered” electrodes in a supercapacitor (SC). Through this approach, direct contact with the electrolyte and polymer material is greatly enhanced. With extensive electrochemical characterisation techniques, we show that the layered electrodes allowed a significant contribution of fast faradic surface reactions to the overall capacitance. The electrochemical performance of the layered-electrode SC outperformed other reported porous polymer-based devices with a specific gravimetric capacitance of 388 F·g−1 and an outstanding energy density of 65 Wh·kg−1 at a current density of 0.4 A·g−1. The device also showed outstanding cyclability with 90% of capacitance retention after 5000 cycles at 1.6 A·g−1, comparable to the reported porous polymer-based SCs. Thus, the introduction of a layered electrode structure would pave the way for more effective utilisation of porous organic polymers in future energy storage/harvesting and sensing devices by exploiting their nanoporous architecture and limiting the negative effects of the carbon/binder matrix.

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Xiong, Huatian, Haiyuan Zou, Weifeng Rong, Yongsong Wang, Hao Dai, Yongfei Ji, and Lele Duan. "A single-step strategy for general construction of metal sub-nanoclusters on graphdiyne." 2D Materials 9, no. 1 (November 1, 2021): 014002. http://dx.doi.org/10.1088/2053-1583/ac2f5f.

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Abstract Metal sub-nanoclusters (SNCs) inherit the metrics of unsaturated active sites and ultrahigh metal utilization from single-atom catalysts (SACs), and they can drive the reactions involving multiple adsorbates by their enriched metal cofactors that beyond SACs. However, the current synthetic strategy offers limited versatility to prepare SNCs due to their subnanometric feature and high active surface. Herein, we demonstrate a universal and facile one-pot reaction to construct wide assortments of metal SNCs with the size of 2 to 3 nm on graphdiyne (GDY), denoted as M-SNCs/GDY (M = Co, Ni, Cu, Ag, Pd, Rh, Au, Ir, and Pt). Systematic investigations reveal that the correlated metal SNCs formation undergone the nucleation and growth process, during which the metal single-atoms were first anchored and then served as nuclei to grow SNCs confined on GDY. The electrochemical CO2 reduction reaction (eCO2RR) catalyzed by Cu-SNC/GDY and a Cu single-atom catalyst on GDY (Cu-SAC/GDY) was investigated to demonstrate the advantages of SNCs over SACs in manipulating the multicomponent reaction. Cu-SNC/GDY exhibited promoted Faradic efficiency (FE) of carbon products and suppressed competing hydrogen evolution reaction compared to the Cu-SAC/GDY. Benefiting from the function of multiple active centers, a C2+ FE of 31.6% was achieved over the Cu-SNC/GDY at −0.7 V versus reversible hydrogen electrode, which is 11-fold higher than that of Cu-SAC/GDY. In situ infrared spectroelectrochemistry confirmed that Cu-SNC/GDY could adsorb more eCO2RR intermediates over Cu-SAC/GDY. This study delivers a single-step strategy for preparing metal SNCs on GDY and expands the scope of SNCs.

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Maged, Ahmed M., Marwa E. Hassanin, Wafaa M. Kamal, Amr H. Abbassy, Mahmoud Alalfy, Ahmed N. Askalani, Ahmed El-Lithy, et al. "Effect of Low-Level Laser Therapy versus Electroacupuncture on Postnatal Scanty Milk Secretion: A Randomized Controlled Trial." American Journal of Perinatology 37, no. 12 (July 21, 2019): 1243–49. http://dx.doi.org/10.1055/s-0039-1693428.

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Abstract Objective Postnatal scanty milk secretion is a common complaint. Some physical and medical interventions were advocated to help milk production. These interventions should be effective and safe for the mother and the infant. This study aimed to compare the effects of low-level laser therapy and electroacupuncture on postnatal scanty milk secretion. Study Design A randomized controlled study conducted on 60 healthy primiparous mothers with insufficient lactation. They were randomly divided into three equal groups: group A (control), group B (those who received low-power He–Ne laser beam on both breasts), and group C (those who received faradic current stimulation at Spleen 6, Liver 3, and Small Intestine 1 acupuncture points on both sides). All participants received 10 mg Domperidone three times a day and were given advice about lactation, nutrition, and fluid intake. Evaluation was done before and after the treatment program. Results The mean serum prolactin, infant weight, and visual analog scale (VAS) score were significantly increased in the three groups posttreatment when compared with their corresponding levels pretreatment. Posttreatment serum prolactin was significantly elevated in group C more than the other two groups (p = 0.001 and 0.012, respectively). Also, it was significantly elevated in group B more than in group A (p = 0.001). The mean value of infant weight was significantly elevated in group C when compared with its corresponding values in both groups A (p = 0.001) and B (p = 0.029). The VAS score was significantly increased in both groups B and C when compared with group A (p = 0.001). Conclusion Electroacupuncture is more effective than low-level laser therapy in increasing postnatal scanty milk secretion. Clinical Trial Registration NCT03806062.

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Mazumder, A. Z. M. Mainul Islam, Asanka Gurukandure, Amanda Siyanka Nellimale Kurian, Subramaniam Somasundaram, and Christopher John Easley. "Understanding Changes of Both Faradaic and Nonfaradaic Currents with Temperature in DNA Monolayer-Based Sensors on Gold Electrodes." ECS Meeting Abstracts MA2022-02, no. 61 (October 9, 2022): 2272. http://dx.doi.org/10.1149/ma2022-02612272mtgabs.

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Electrochemical sensors are well studied for detecting DNA, RNA, small molecules, inorganic ions, etc. Using the latest DNA-based sensors, a change in the location of a redox reporter attached to an electrode-bound nucleic acid gives rise to faradaic current changes, which can be monitored by square wave voltammetry (SWV) and used for sensing of various analytes. However, the nonfaradaic current generated along with the faradaic current has often been viewed as a limiting factor in sensor performance and either subtracted or ignored. Nonfaradaic current can be suppressed somewhat by surface blocking and reduced electrode surface area, and our group recently introduced a differential potentiostat (DiffStat) that provided efficient, in-hardware subtraction. On the other hand, removal of nonfaradaic current may lead to loss of important information embedded within. Moreover, a change in temperature can affect both faradaic and nonfaradaic currents by altering the movement of DNA strands and other ions present in the solution. Usually, faradaic current is proportional to the temperature. However, temperature-dependent changes in nonfaradaic current have not been well studied in DNA monolayer-based sensors. In this study, the changes in both faradaic and nonfaradaic currents were monitored in an electrochemical DNA hybridization assay. A thiolated DNA (thio-DNA) monolayer was assembled onto gold electrodes, and current was measured at different square wave frequencies (1 to 1000 Hz). The DNA analyte and the methylene blue tagged DNA (MB-DNA) were hybridized with the thio-DNA separately to compare the signals. Using an in-house built Peltier controller, the effects of temperature were monitored during operation of an analyte-induced proximity assay with SWV readout. In-house written MATLAB code was developed to automatically analyze each set of raw SWV data. Within this code, a polynomial baseline was calculated in the vicinity of the redox potential of MB-DNA (around -200 mV) to allow faradaic and nonfaradaic currents to be separated, post assay. Two-dimensional heatmaps were generated to study the variation of these currents with both temperature and square wave frequency. The faradaic current increased up to a certain temperature and then decreased due to dissociation (or melting) of the DNA from the surface. The nonfaradaic current, on the other hand, increased with temperature in a viscosity-dependent manner and also increased with the square wave frequencies as expected from a capacitive, single exponential time decay. Current changes exhibited by the DNA sensors upon analyte binding and temperature fluctuation suggested that both faradaic and nonfaradaic signals could be used for multidimensional analysis of sensor responses in the future. Figure 1

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Knuettel, Sebastian, and Denise Gabuzda. "Probing the B-fields of AGN jets on kiloparsec scales - NGC 6251." Proceedings of the International Astronomical Union 14, S342 (May 2018): 244–45. http://dx.doi.org/10.1017/s1743921318005161.

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AbstractBy constructing images of the Faraday rotation measure (RM) of large scale astrophysical jets, the line-of-sight magnetic field component and electron density in the region of Farady rotation can be investigated. A significant gradient in the RM transverse to the jet direction may indicate a corresponding gradient in the line-of-sight magnetic field, implying a toroidal or helical magnetic field, which would, in turn, imply the presence of an associated electrical current in the jet. The detection of such large scale gradients can reliably demonstrate that helical or toroidal fields can persist to large distances from the central AGN. We present a kiloparsec-scale Faraday rotation map of NGC 6251 that shows statistically significant transverse RM gradients across its kiloparsec scale jet structure that imply an outward current.

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Kireev, S. Yu, Yu P. Perelygin, S. N. Kireeva, and M. J. Jaskula. "Methods to Determine the Current Efficiency in AC Electrolysis." Arabian Journal for Science and Engineering 46, no. 1 (July 27, 2020): 343–52. http://dx.doi.org/10.1007/s13369-020-04786-y.

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AbstractThe paper presents several methods (analytical, electromechanical and electronic) for determining the cathodic current efficiency of the metal deposition processes carried out by AC or pulse current. Based on the results of own experimental researches (for indium, cadmium, nickel, tin and zinc), the appropriate equations are given and the distribution of both faradaic and non-faradaic parts of charge (charging of the electrode double layer) is calculated.

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Zhang, Cheng, Zehui Liu, Jintao Qiu, Han Bai, Fei Kong, and Tao Shao. "Measurement of runaway electron beam current in nanosecond-pulse discharges by a Faraday cup." Laser and Particle Beams 36, no. 3 (September 2018): 369–75. http://dx.doi.org/10.1017/s026303461800040x.

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AbstractMeasurement of runaway electron beam (REB) is essential to investigate behavior of runaway electrons produced in nanosecond-pulse gas discharge. A Faraday cup is designed to measure the REB current in nanosecond-pulse discharge when the applied dV/dt is 75 kV/ns. The Faraday cup considers the impendence match with the oscilloscope and the design of the receiving part. The experimental results show that the measured REB current has a rise time of 348 ps and a full width at half maximum of 510 ps. The comparison of the measurement results by the Faraday cup and a REB collector confirm that the Faraday cup is able to measure REB current in nanosecond-pulse discharge. Furthermore, consecutive waveforms of the REB currents show stable results by using the designed Faraday cup. In addition, effects of the interelectrode gap, gas pressure, and cathode material on the REB current are investigated by the designed Faraday cup, and the measurement results provide characteristics of REB current under different conditions. The REB current decreases when the gap spacing or gas pressure increases. REB current increases with the cathode diameter. It indicates that the high-energy electrons are generated not only at the edge of the cathode but also on the side surface of the cathode.

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Sun, Chia-Liang, Cheng-Hsuan Lin, Chia-Heng Kuo, Chia-Wei Huang, Duc Dung Nguyen, Tsu-Chin Chou, Cheng-Ying Chen, and Yu-Jen Lu. "Visible-Light-Assisted Photoelectrochemical Biosensing of Uric Acid Using Metal-Free Graphene Oxide Nanoribbons." Nanomaterials 11, no. 10 (October 13, 2021): 2693. http://dx.doi.org/10.3390/nano11102693.

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In this study, we demonstrate the visible-light-assisted photoelectrochemical (PEC) biosensing of uric acid (UA) by using graphene oxide nanoribbons (GONRs) as PEC electrode materials. Specifically, GONRs with controlled properties were synthesized by the microwave-assisted exfoliation of multi-walled carbon nanotubes. For the detection of UA, GONRs were adopted to modify either a screen-printed carbon electrode (SPCE) or a glassy carbon electrode (GCE). Cyclic voltammetry analyses indicated that all Faradaic currents of UA oxidation on GONRs with different unzipping/exfoliating levels on SPCE increased by more than 20.0% under AM 1.5 irradiation. Among these, the GONRs synthesized under a microwave power of 200 W, namely GONR(200 W), exhibited the highest increase in Faradaic current. Notably, the GONR(200 W)/GCE electrodes revealed a remarkable elevation (~40.0%) of the Faradaic current when irradiated by light-emitting diode (LED) light sources under an intensity of illumination of 80 mW/cm2. Therefore, it is believed that our GONRs hold great potential for developing a novel platform for PEC biosensing.

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Stucky, Chase, and Michael A. Johnson. "Improved Serotonin Measurement with Fast-Scan Cyclic Voltammetry: Mitigating Fouling by SSRIs." Journal of The Electrochemical Society 169, no. 4 (April 1, 2022): 045501. http://dx.doi.org/10.1149/1945-7111/ac5ec3.

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Selective serotonin reuptake inhibitors (SSRIs) have been used for decades to treat disorders linked to serotonin dysregulation in the brain. Moreover, SSRIs are often used in studies aimed at measuring serotonin with fast-scan cyclic voltammetry (FSCV) in living tissues. Here, we show that three different SSRIs—fluoxetine, escitalopram, and sertraline—significantly diminish the faradaic oxidation current of serotonin when employing the commonly used Jackson waveform. Coating carbon-fiber microelectrodes (CFMs) with Nafion resulted in further degradation of peak current, increased response times, and decreased background charging currents compared to bare CFMs. To decrease fouling, we employed a recently published extended serotonin waveform, which scans to a maximum positive potential of +1.3 V, rather than +1.0 V used in the Jackson waveform. Use of this waveform with bare CFMs alleviated the decrease in faradaic current, indicating decreased electrode fouling. Collectively, our results suggest that fouling considerations are important when designing FSCV experiments that employ SSRIs and that they can be overcome by using the appropriate waveform.

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Wosiak, Gabriel, Dyovani Coelho, Evaldo B. Carneiro-Neto, Ernesto C. Pereira, and Mauro C. Lopes. "Numerical Resolving of Net Faradaic Current in Fast-Scan Cyclic Voltammetry Considering Induced Charging Currents." Analytical Chemistry 92, no. 23 (November 11, 2020): 15412–19. http://dx.doi.org/10.1021/acs.analchem.0c03026.

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Graves, David Alexandro, Lucas Bitencourt Theodoroviez, Rafael Claro Firmino, Richelmy Magi Sanches, Neidenei Ferreira, Dalva Alves de Lima Almeida, and Emerson Sarmento Gonçalves. "Evaluation of the Effects of Substrate Heat Treatment and Monomer/Acid Ratio Synthesis Parameters on the Performance of PANI/CFF Electrodes." ECS Meeting Abstracts MA2022-02, no. 1 (October 9, 2022): 20. http://dx.doi.org/10.1149/ma2022-02120mtgabs.

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The association of capacitive charging of the double-layer and a faradic redox reaction is desirable on carbon fiber felt (CFF) when oxygen functional groups or other materials such as conducting polymers are present on its surface enhancing its capacitive properties. In this work, a systematic study of the composites formed by carbon fiber felt felt produced at two different heat treatment temperatures (HTT) of 1000 and 2000 ºC and polyaniline (PANI) was performed upon two approaches: influence of heat treatment temperatures of substrate CFF and monomer/acid ratio. CFF samples were produced from polyacrylonitrile (PAN) precursor at HTT of 1000 and 2000 ºC, with step temperature of 330 ºC h-1 under nitrogen atmosphere. The maximum level temperature was kept for 30 min and then, cooled down to room temperature. The CFF samples were cut in 1 cm2 with thickness about 2 mm. Afterwards, the PANI was electrodeposited on CFF under galvanostatic mode with current density of 5 mA cm-2, using 1:1 and 2:1 H2SO4/aniline mol L-1 aqueous solution at deposition time of the 1350 seconds, for both proportions acid/monomer. The obtained PANI/CFF binary composite was washed in acid solution and vacuum dried. The morphological and structural analyses were investigated by Field emission gun-scanning (FEG-SEM), Surface Area Analysis (BET – Brunauer, Emmett and Teller), Thermogravimetric analysis (TG) and Fourier-Transform Infrared Spectroscopy (FT-IR). Electrochemical responses were analyzed by galvanostatic charge/discharge, electrochemical impedance spectroscopy, and cyclic voltammetry. The electrochemical analyses are recorded in a three electrodes system using Ag/AgCl electrode as reference electrode and a platinum sheet as counter-electrode in deaired solution with N2 using a potentiostat PGSTAT 302 with FRA module (Metrohm – AUTOLAB). The charge/discharge (CD) tests are obtained by applying constant current I of ±1.0, 0.75 and 0.5 mA (Ecut-off from -0.1 to 0.78 V vs. Ag/AgCl). Cyclic voltammograms (CV) are recorded in previously defined potential at sweep rate range from 10, 25, 50, 75 and 100 mV s−1. The electrochemical impedance spectroscopy (EIS) measurements are performed at open circuit potential (OCP) with ± 10 mV of the potential amplitude in the frequency range from10-3 to 105 Hz in 1.0 mol L-1 H2SO4. As can be seen, the FFC 2000 2:1 sample with 1350 seconds of synthesis presents higher specific capacitance as well as higher coulombic efficiency compared to FFC 2000 1:1 sample also with 1350 seconds of synthesis, with values at around 80 F/g and 90% respectively. On the other hand, the CFF 1000 1:1 sample with 1350 seconds of synthesis present higher values (33 F/g and 100%) than the sample CFF 1000 2:1 with 1350 seconds of synthesis (26 F/g and 100%). In addition, the increase in the intensity of the Faradaic peaks that were provided by the greater presence of the monomer synthesized on the surface of the substrate. The analogous way the excess of monomer may favor the formation of polymer on polymer which will intensify, also the redox peaks and will also favor the formation of reticles providing that form para- (cross) bonds in addition to ortho- (linear) bonds. Therefore, it is suggested that in comparison to the FFC 2000 samples we have a greater favor of para- in the polymeric chains, for the FFC 1000 samples it is suggested that it has formed a greater number of ortho-type bonds, as can be seen in the FT-IR data. By FEG-SEM it is possible to verify that in CFF 2000 2:1 1350 seconds there is a smaller formation of the polymer film with agglomerates by the entire structure of the felt comparing with the microscopy of the sample CFF 2000 1:1 1350 seconds. Also, a smaller surface area and/or a smaller amount of pores available as noted in the N2 adsorption isotherm but it is similarly observed that polymer chains in overlapping layers, which also suggests the formation of para- providing lower values of specific capacitance and coulombic efficiency. Note that the N2 adsorption isotherm suggests that the CFF 2000 1:1 sample has greater surface area and/or greater amount of pores available on its surface compared to fiber under the same conditions, which contribute to the greater accumulation of charge and coloumbic efficiency on storage devices.

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Chopart, J. P., O. Aaboubi, E. Merienne, A. Olivier, and J. Amblard. "MHD-control on limiting Faradaic currents." Energy Conversion and Management 43, no. 3 (February 2002): 365–71. http://dx.doi.org/10.1016/s0196-8904(01)00110-8.

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Takahashi, Yoshitaka, Tetsuya Shimoyama, and Toshihiko Yoshino. "Accurate Faraday effect current sensor." Optics & Laser Technology 25, no. 3 (June 1993): 201. http://dx.doi.org/10.1016/0030-3992(93)90069-r.

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48

Ciepiela, Filip, and Małgorzata Jakubowska. "Faradaic and Capacitive Current Estimation by DPV-ATLD." Journal of The Electrochemical Society 164, no. 12 (2017): H760—H769. http://dx.doi.org/10.1149/2.0881712jes.

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Hariyanto, H., Widodo W. Purwanto, and Roekmijati W. Soemantojo. "CO₂ current efficiency in direct ethanol fuel cell." Jurnal Teknik Kimia Indonesia 6, no. 1 (October 2, 2018): 581. http://dx.doi.org/10.5614/jtki.2007.6.1.6.

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In this present work, a systematically study on 20% PtCeO2/C catalyst for ethanol electro-oxidation in direct ethanol fuel cell were carried out. For cathode catalyst, a commercial catalyst of 40% Pt/C from ETEK was applied. Catalysts were printed on to carbon paper of TGPH 060 and sandwiched into membrane electrode assembly (MEA) and then arranged infitel cell with the geometric area 1.2 cm2. As an electrolyte, we used Nafion 117 from Du Pont. On-line Differential Electrochemical Mass Spectrometry (DEMS) measurement infuel cell setup was carried out in order to determine the activity and selectivity which was indicated by result of Faradaic current and CO2 current efficiency of ethanol electro-oxidation respectively. PtCeO2/C was significantly improving the selectivity of CO formation n comparison to the commercial catalyst of 20% Pt/C from A/fa Aesar- Johnson Mattews. Increasing of" selectivity was shown by the increase of CO2 current efficiency of ethanol oxidation of about 20 percent in comparison to references catalyst of 20% Pt/C (AlfaAesar-JM).Keywords: Ceria, Membrane Electrode Assembly (MEA), DEMS, Ethanol Electro-OxidationAbstrakPada peneletian ini dilakukan kajian sistematis terhadap katalis 20% PtCeO2/C yang akan digunakan pada elektro-oksidasi etanol pada sel bahan bakar etanol langsung. Untuk katalis katoda, digunakan katalis komersial 40% Pt/C dari ETEK. Katalis tersebut diaplikasikan pada kertas karbon TGPH 060 dan diselipkan pada rangkaian membran electroda (MEA) dan kemudian disusun pada sel bahan bakar yang memiliki luas geometris 1.2 cm2. Sebagai elektrolit, digunakan Nafion 117 produksi Du Pont. Pengukuran On-line oleh Spektrometri Massa Elektrokimia Diferensial atau Differential Electrochemical Mass Spectrometry (DEMS) pada pemasangan sel bahan bakar telah dilakukan untuk menentukan aktivitas dan selektivitasnya yang dapat ditunjukkan masing-masing oleh hasil arus Faradik dan efisiensi arus CO2 dari elektro-oksidasi etanol. Dari hasil percobaan diperoleh bahwa PtCeO2/C dapat secara signifikan meningkatkan selektivitas untuk membentuk CO2 dibandingkan terhadap katalis komersial 20% Pt/C dari A/fa Aesar-Johnson Mattews. Kenaikan selektivitas ditunjukkan oleh kenaikan efisiensi arus CO2pada oksidasi ethanol sebesar 20 persen dibandingkan terhadap katalis rujukan 20% Pt/C (AlfaAesar-JM).Kata Kunci: Ceria, Membrane Electrode Assembly (MEA), DEMS, Elektro-Oksidasi Etanol

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Bush, S. P., and D. A. Jackson. "Dual-channel Faraday-effect current sensor capable of simultaneous measurement of two independent currents." Optics Letters 16, no. 12 (June 15, 1991): 955. http://dx.doi.org/10.1364/ol.16.000955.

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Journal articles on the topic 'Faradic current'

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