scholarly journals Preparation and electrochemical properties of a novel porous Ti/Sn–Sb-RuOx/β-PbO2/MnO2 anode for zinc electrowinning

RSC Advances ◽  
2021 ◽  
Vol 11 (31) ◽  
pp. 19136-19146
Author(s):  
Buming Chen ◽  
Jianhua Liu ◽  
Shichuan Wang ◽  
Hui Huang ◽  
Yapeng He ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Zinc Electrowinning ◽  
Oxidation Peak ◽  
Peak Current ◽  
Porous Ti ◽  
Negative Current ◽  
Large Peak ◽  
Current Value ◽  
Plating Solution

PbO2 electrodes exhibit symmetry on the CV curve in MnSO4 bath (oxidation peak occurs at 1.00–1.40 V) and asymmetry in Mn(NO3)2 plating solution (negative current value at 1.00–1.18 V). The current rapidly rises to a large peak current at 1.25 V.

scholarly journals Surface Modification Effect and Electrochemical Performance of LiOH-High Surface Activated Carbon as a Cathode Material in EDLC

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2187
Author(s):  
Zambaga Otgonbayar ◽  
Sunhye Yang ◽  
Ick-Jun Kim ◽  
Won-Chun Oh
Keyword(s):  
Activated Carbon ◽  
Cathode Material ◽  
Electrochemical Properties ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Oxidizing Agent ◽  
Peak Current ◽  
X Ray ◽  
Current Value

This study aimed to improve the performance of the activated carbon-based cathode by increasing the Li content and to analyze the effect of the combination of carbon and oxidizing agent. The crystal structure and chemical structure phase of Li-high surface area activated carbon material (Li-HSAC) was analyzed by X-ray diffraction (XRD) and Raman spectroscopy, the surface state and quantitative element by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and the surface properties with pore-size distribution by Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH) and t-plot methods. The specific surface area of the Li-YP80F is 1063.2 m2/g, micropore volume value is 0.511 cm3/g and mesopore volume is 0.143 cm3/g, and these all values are higher than other LiOH-treated carbon. The surface functional group was analyzed by a Boehm titration, and the higher number of acidic groups compared to the target facilitated the improved electrolyte permeability, reduced the interface resistance and increased the electrochemical properties of the cathode. The oxidizing agent of LiOH treated high surface area of activated carbon was used for the cathode material for EDLC (electric double layer capacitor) to determine its electrochemical properties and the as-prepared electrode retained excellent performance after 10 cycles and 100 cycles. The anodic and cathodic peak current value and peak segregation of Li-YP80F were better than those of the other two samples, due to the micropore-size and physical properties of the sample. The oxidation peak current value appeared at 0.0055 mA/cm2 current density and the reduction peak value at –0.0014 mA/cm2, when the Li-YP80F sample used to the Cu-foil surface. The redox peaks appeared at 0.0025 mA/cm2 and –0.0009 mA/cm2, in the case of using a Nickel foil, after 10 cycling test. The electrochemical stability of cathode materials was tested by 100 recycling tests. After 100 recycling tests, peak current drop decreased the peak profile became stable. The LiOH-treated high surface area of activated carbon had synergistically upgraded electrochemical activity and superior cycling stability that were demonstrated in EDLC.

scholarly journals Electrochemical antioxidant screening and evaluation based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE)

2020 ◽  
Vol 18 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Ping Tang ◽  
Xiaosheng Tang ◽  
Shiyong Mei ◽  
Yixi Xie ◽  
Liangliang Liu ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Capacity ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Carbon Electrode ◽  
Oxidation Peak ◽  
Modified Glassy Carbon Electrode ◽  
Peak Current ◽  
Oxidation Peak Current ◽  
Antioxidant Capacities

AbstractIn this study, an electrochemical biosensor based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE) was developed and employed for antioxidant screening and antioxidant capacity evaluation. The oxidation peak current of guanine was improved and nearly tripled after modifications of chitosan and MoS2 nanosheet. The immobilized guanine could be damaged by hydroxyl radicals generated in Fenton solution. However, in the presence of antioxidants, the guanine was protected and the oxidation peak current of guanine increased. This process mimics the mechanism of antioxidant protection in human body. The factors affecting preparation of sensor and detection of antioxidant capacity were optimized. At the optimum conditions, the guanine/CS/MoS2/GCE showed wide linear range, low detection limit, satisfactory reproducibility and stability for detection. Ascorbic acid was used as a model antioxidant to evaluate the antioxidant capacity. A good linearity was observed with a correlation coefficient of 0.9959 in the concentrations between 0.5 and 4.0 mg L-1. The antioxidant capacities of three flavonoids were also tested and the rank of antioxidant capacities was ascorbic acid (51.84%), quercetin (45.82%), fisetin (34.39%) and catechin (16.99%). Due to the rapid measurement and low cost, this sensor could provide an available sensing platform for antioxidant screening and evaluation.

scholarly journals Electrochemical Response of Clay/Polyelectrolyte Composite Barrier Coatings

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1173
Author(s):  
Sumin Kim ◽  
Clare Chisu Byeon ◽  
Sung Yeol Kim
Keyword(s):  
Mass Transport ◽  
Indigo Carmine ◽  
Copper Substrate ◽  
Layer By Layer ◽  
Potential Cycling ◽  
Peak Current ◽  
Redox Peak ◽  
Coated Electrode ◽  
Redox Peak Current ◽  
Current Value

Composite materials made of polymer and clay are effective at blocking mass transport. In this study, the blocking efficacy of layer-by-layer (LbL) coatings of exfoliated montmorillonite (MMT) and polyethylenimine (PEI) was studied using cyclic voltammetry and a redox couple, indigo carmine (IC). The pH of the MMT solution was varied from 4 to 10 to prepare LbL coatings of different surface roughness on metal substrates. It was found that the coated electrode had a lower redox peak current value than without the coating, demonstrating the reduction of the mass transport of IC to the metal surface. The peak values decreased with decreasing the coating’s roughness and increasing the number of layers, indicating that the blocking capability can be controlled by changing the deposition conditions. Smooth LbL coatings deposited with MMT at pH 4 showed the highest blocking efficacy up to 97.5%. The IC adsorbed at the interface between the coating and the metal substrate was found to cause the peak current measured for the coated electrode. It was also confirmed that the same coating on the copper substrate reduced the corrosion of the copper during the electrochemical potential cycling.

scholarly journals Signatures of large peak current lightning strokes during an unusually intense sprite-producing thunderstorm in southern England

2021 ◽  
Vol 249 ◽  
pp. 105357
Author(s):  
Andrea Pizzuti ◽  
Jonathan M. Wilkinson ◽  
Serge Soula ◽  
Janusz Mlynarczyk ◽  
Ivana Kolmašová ◽  
...  
Keyword(s):  
Peak Current ◽  
Southern England ◽  
Large Peak

Research on the Machining Performance of SiC/Al Composites Utilizing the BEAM Process

2015 ◽  
Author(s):  
Jipeng Chen ◽  
Lin Gu ◽  
Hui Xu ◽  
Wansheng Zhao
Keyword(s):  
Material Removal ◽  
Removal Rate ◽  
Machining Efficiency ◽  
Machining Performance ◽  
Peak Current ◽  
Tool Wear Ratio ◽  
Large Peak ◽  
Performance Results ◽  
The Relationship ◽  
Blasting Erosion Arc Machining

The Blasting Erosion Arc Machining (BEAM) process was applied to improve the machining efficiency of SiC/Al composites. A set of experiments were conducted on 20 vol% SiC/Al composites to find out the relationship between the parameters and machining performance. Results revealed that when the peak current was 500 A, the material removal rate (MRR) could be greater than 8,200 mm3/min and the tool wear ratio (TWR) was about 2%. Besides, the influence of polarity on the surface properties was also studied by using scanning electron microscope (SEM) and metalloscope. It disclosed that machining with a large peak current and a negative BEAM is suitable for bulk mass material removal, while the surface quality could be improved by applying the positive BEAM. Finally, a machined sample demonstrated the fesibility of BEAM for the machining of SiC/Al materials.

Effects of polyaniline on electrochemical properties of composite inert anodes used in zinc electrowinning

2012 ◽  
Vol 22 (7) ◽  
pp. 1693-1700 ◽  
Author(s):  
Peng ZHAN ◽  
Rui-dong XU ◽  
Li-ping HUANG ◽  
Bu-ming CHEN ◽  
Jian-feng ZHOU
Keyword(s):  
Electrochemical Properties ◽  
Zinc Electrowinning ◽  
Inert Anodes

Seasonal, Regional, and Storm-Scale Variability of Cloud-to-Ground Lightning Characteristics in Florida

2011 ◽  
Vol 139 (6) ◽  
pp. 1826-1843 ◽  
Author(s):  
Scott D. Rudlosky ◽  
Henry E. Fuelberg
Keyword(s):  
Structural Damage ◽  
Warm Season ◽  
Atmospheric Conditions ◽  
Cool Season ◽  
Peak Current ◽  
Close Proximity ◽  
Cloud To Ground Lightning ◽  
Large Peak ◽  
Reversed Polarity

Abstract Seasonal, regional, and storm-scale variations of cloud-to-ground (CG) lightning characteristics in Florida are presented. Strong positive CG (+CG) and negative CG (−CG) flashes (i.e., having large peak current) are emphasized since they often are associated with strong storms, structural damage, and wildfire ignitions. Although strong −CG flashes are most common during the warm season (May–September) over the peninsula, the greatest proportion of strong +CG flashes occurs during the cool season (October–April) over the panhandle. The warm season exhibits the smallest +CG percentage but contains the greatest +CG flash densities, due in part to more ambiguous +CG reports (15–20 kA). The more frequent occurrence of ambiguous +CG reports helps explain the unusually small average +CG peak current during the warm season, whereas strong +CG reports (>20 kA) appear to be responsible for the greater average warm season +CG multiplicity. The −CG flash density, multiplicity, and peak current appear to be directly related, exhibiting their greatest values during the warm season when deep storms are most common. A case study examines the atmospheric conditions and storm-scale processes associated with two distinct groups of storms on 13–14 May 2007. Although these groups of storms form in close proximity, several factors combine to produce predominately strong +CG and −CG flashes in the northern (south Georgia) and southern (north Florida) regions, respectively. Results suggest that heat and smoke very near preexisting wildfires are key ingredients in producing reversed-polarity (+CG dominated) storms that often ignite subsequent wildfires.

In situ detection of intermediates from the interaction of dissolved sulfide and manganese oxides with a platinum electrode in aqueous systems

2017 ◽  
Vol 14 (3) ◽  
pp. 178 ◽  
Author(s):  
Yao Luo ◽  
Yougang Shen ◽  
Lihu Liu ◽  
Jun Hong ◽  
Guohong Qiu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Manganese Oxides ◽  
Platinum Electrode ◽  
Aqueous Systems ◽  
Oxidation Peak ◽  
Peak Current ◽  
Oxidation Peak Current ◽  
Dissolved Sulfide ◽  
In Situ Detection

Environmental contextDissolved sulfide results in soil acidification and subsequent contaminant leaching via oxidation processes, usually involving manganese oxides. In this work, redox processes were monitored in situ by cyclic voltammetry and HS– concentrations were semi-quantitatively determined. The method provides qualitative and semi-quantitative assessment for dissolved sulfide and its oxidation intermediates in aqueous systems. AbstractDissolved sulfide can be oxidised by manganese oxides in supergene environments, while the intermediates including S0, S2O32– and SO32– are easily oxidised by oxygen in air, resulting in some experimental errors in conventional analyses. In this work, the electrochemical behaviours of HS–, S2O32– and SO32– on a platinum electrode were studied by cyclic voltammetry and constant potential electrolysis, and in situ detection of the intermediates was conducted in aqueous systems of HS– and manganese oxides. The results showed that HS– was first oxidised to S0, and then transformed to SO42–. The peak current for the oxidation of HS– to S0 had a positive linear correlation with the used starting HS– concentration. S2O32– and SO32– were directly electrochemically oxidised to SO42–. The oxidation current peak potentials at 0, 0.45 and 0.7V were respectively observed for HS–, S2O32– and SO32– at pH 12.0. Cyclic voltammetry was conducted to monitor the redox processes of HS– and manganese oxides. The oxidation peak current of HS– to S0 decreased, and that of S2O32– to SO42– was observed to increase as the reaction proceeded. The rate of the decrease of the oxidation peak current of HS– indicated that the oxidation activity followed the order of birnessite>todorokite>manganite.

Sensitive detection of bisphenol A based on a ratiometric electrochemical aptasensor

2016 ◽  
Vol 94 (5) ◽  
pp. 509-514 ◽  
Author(s):  
Yunqing Liu ◽  
Xia Zhang ◽  
Junshuai Yang ◽  
Erhu Xiong ◽  
Xiaohua Zhang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Bisphenol A ◽  
Selective Detection ◽  
Electrochemical Aptasensor ◽  
Oxidation Peak ◽  
Current Ratio ◽  
Peak Current ◽  
Practical Applications ◽  
Double Stranded Dna ◽  
Highly Sensitive

A new ratiometric electrochemical aptasensor has been developed for highly sensitive and selective detection of bisphenol A (BPA). The double-stranded DNA (dsDNA), consisting of the BPA aptamer (DNA1) and methylene blue (MB)-labeled complementary DNA (cDNA), was immobilized on a gold nanoparticle (AuNP) modified glassy carbon (GC) electrode. In the presence of BPA, the specific BPA–aptamer interaction drove the release of the MB-labeled cDNA from the electrode surface. As a result, the oxidation peak current of MB (IMB) decreased and that of BPA (IBPA) increased. The peak current ratio (IBPA/IMB) of BPA and MB was linear with the concentration of BPA in the range from 1 to 100 pmol/L with a detection limit of 0.6 pmol/L. The detection limit is much lower than that obtained by most of the reported electrochemical methods. On the other hand, the developed aptasensor possesses good selectivity, reproducibility, and stability, and the related sensing structure is very simple, showing promising practical applications in BPA assays.

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