scholarly journals Anodic Polarization Behavior of X80 Steel in Na2SO4 Solution under High Potential and Current Density Conditions

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 394 ◽  
Author(s):  
Runzhi Qin ◽  
Yanxia Du ◽  
Zhenchang Xu ◽  
Minxu Lu
Keyword(s):  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Anodic Polarization ◽  
High Potential ◽  
X Ray ◽  
High Voltage Direct Current ◽  
Corrosion Rates ◽  
Polarization Behavior ◽  
Galvanostatic Polarization ◽  
X80 Steel

X80 steel has great risk of corrosion in high voltage direct current (HVDC) interference cases. In this study, the anodic polarization behavior of X80 steel under high potential and current density in Na2SO4 solution was investigated. The I × R drop was eliminated using current interrupt technique during the potentiodynamic measurement. Therefore, the real polarization curve was obtained. The corrosion behavior was investigated by galvanostatic polarization, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results show a new form of passivation route. The steel dissolved actively below −0.388 VSCE, then became partly passivated from −0.388 to 1.448 VSCE, and fully passivated above 1.448 VSCE. The passive film was formed containing Fe2O3 and FeOOH, and resistant to SO42− ions. It not only blocked the direct dissolution of steel, but also facilitated oxygen evolution. The corrosion rates of steel samples decreased after the passivation.

scholarly journals Influence of Cl− ions on anodic polarization behaviour of API X80 steel in high potential/current density conditions in Na2SO4 solution

RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 7698-7704
Author(s):  
Runzhi Qin ◽  
Yanxia Du ◽  
Zhenchang Xu ◽  
Minxu Lu
Keyword(s):  
Current Density ◽  
Anodic Polarization ◽  
High Potential ◽  
High Concentration ◽  
Low Concentration ◽  
Polarization Behaviour ◽  
X80 Steel

X80 steel gets passivated in high potential/current density conditions in Na2SO4 solution. Low concentration of Cl− ions weakens the passivation. High concentration of Cl− ions totally prevents the passivation.

Simplified Synthesis of 3D Flexible Reduced Graphene Oxide-Wrapped NiCo2O4 Nanowires for High-Performance Supercapacitor

2018 ◽  
Vol 10 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Chao Pan ◽  
Hongyu Sun ◽  
Jingyi Gao ◽  
Yucai Hu ◽  
Jing Wang
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Current Density ◽  
Three Dimensional ◽  
Simple Method ◽  
X Ray ◽  
Reduced Graphene

We introduced a simple method to construct novel three-dimensional (3D) flexible hierarchical nanocomposites by combining (1D) NiCo2O4 nanowires with 2D reduced graphene oxide (rGO) sheets. The hierarchical nanocomposite structure of rGO-wrapped NiCo2O4 (rGO-NiCo2O4) was confirmed by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The results indicated that NiCo2O4 nanowires were successfully wrapped in rGO and the morphology of the rGO-NiCo2O4 showed a three-dimensional porous structure with NiCo2O4 being homogeneously distributed in the rGO. Given their apparent advantages, these two different nanostructures were evaluated as electrodes for high-performance supercapacitors. These electrodes exhibited a high capacitance of 1824.8 F·g–1 at a current density of 0.5 A·g–1, and an excellent cycling performance extending to 5000 cycles at a high current density of 4 A·g–1. Our results clearly demonstrate that rGO sheets on NiCo2O4 nanowires can substantially improve the capacitive performance of materials and ultimately increase the cycling stability of supercapacitors. The hierarchical binary nanocomposites show excellent electrochemical properties for energy storage applications, evidencing their potential application as supercapacitors.

Electrochemical performances of pyrolytic-cellulose for lithium and sodium ion batteries anode

2020 ◽  
Vol 10 (10) ◽  
pp. 1685-1691
Author(s):  
Lingfang Li ◽  
Dan Chen ◽  
Sichao Su ◽  
Bin Zeng
Keyword(s):  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
High Current Density ◽  
Energy Storage Materials ◽  
Electrochemical Performances ◽  
Hard Carbon ◽  
X Ray ◽  
Sodium Storage ◽  
Charge Discharge

At present, due to the depletion of fossil fuels and increasingly serious environmental problems, more and more attention has been paid to the development and application of functional nanostructured materials as renewable energy storage materials. Herein, lithium and sodium storage properties of hard carbons (HC) prepared by pyrolyzing cellulose were investigated. The orderliness and bonding mode of hard carbon were analyzed by X-Ray Diffraction and X-ray Photoelectron Spectroscopy. Electrochemical properties were characterized by Cyclic Voltammetry, electrochemical Impedance Spectroscopy and charge–discharge test. Results showed that the cellulose-derived hard carbon had good lithium and sodium storage performance. The charge–discharge capacity was about 400 mAh/g and 240 mAh/g, respectively, at a current density of 0.2 A/g, and capacity was also stable under high current density of 2 A/g.

Anodic Polarization Behavior Of Nickel-Chromium Alloys In Sulfuric Acid Solutions

CORROSION ◽  
1965 ◽  
Vol 21 (9) ◽  
pp. 277-287 ◽  
Author(s):  
J. R. MYERS ◽  
F. H. BECK ◽  
M.G. FONTANA
Keyword(s):  
Sulfuric Acid ◽  
Critical Current Density ◽  
Critical Current ◽  
Acid Concentration ◽  
Current Density ◽  
Anodic Polarization ◽  
Chromium Content ◽  
Acid Solutions ◽  
Polarization Behavior ◽  
Sulfuric Acid Solutions

Abstract Anodic polarization behavior of annealed high-purity Ni, Cr and selected Ni-Cr alloys in hydrogen-saturated, 1, 5, 10 and 20N sulfuric acid solutions was investigated at 25 ± 1 C (77 F) using a potentiostatic technique. All specimens except pure Ni in 20N acid had an active-to-passive transition. Decreasing acid concentration increased passive potential range of pure Ni while acid concentration did not appreciably affect the passive region of pure Cr or the Ni-Cr alloys. Increasing acid concentration and decreasing chromium content increased the secondary passivation tendency in the transpassive region. No oxygen evolved in the transpassive region except for pure Ni and the higher nickel alloys. Tafel slopes for anodic dissolution, early transpassive region and oxygen evolution were determined. Corrosion potentials for pure Ni and Ni-Cr alloys containing up to 90 w/o Cr behaved as a reversible hydrogen electrode over the pH range 1.63 to −0.44. This linear relationship did not exist for the higher acid concentrations. Slope dependence for pure Cr and the 99Cr-1Ni alloy was −0.110. A minimum in critical current density versus percent Cr curves was established at 90 to 95 w/o Cr. Passivation potentials were determined. Passive current density decreased with increasing chromium content over the composition range 0 to 33 w/o Cr. It was established that increased specimen purity decreases the magnitude of critical current density and shifts corrosion and passivation potentials in the noble potential direction.

scholarly journals Construction of Ni-Mo-P heterostructures with efficient hydrogen evolution performance under acidic condition

2021 ◽  
Author(s):  
Tian-Yun Chen ◽  
Ya-Qi Zhang ◽  
Ying-Yan Fu ◽  
Min Qian ◽  
Hao-Jiang Dai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Clean Energy ◽  
Hydrogen Energy ◽  
Durability Test ◽  
X Ray ◽  
Onset Potential

Abstract Hydrogen energy is regarded as one of the most important clean energy in the 21st century, and improving the catalytic efficiency of hydrogen evolution reaction (HER) is the basis for realizing the large-scale hydrogen production. Transition metal phosphides (TMPs) were proved to be efficient electrocatalysts for HER. In this work, we first synthesized the nickel-molybdenum bimetallic precursors, followed by high-temperature calcination in air. Finally, NiMoP/MoP nanorods (Ni-Mo-P NRs) was obtained by chemical vapor deposition (CVD) of phosphating. The target catalyst of Ni-Mo-P NRs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). For Ni-Mo-P NRs, the electrochemical test in 0.5 M H2SO4 solution for HER showed that the optimal feeding ratio was Ni: Mo = 1:1. And the Ni1-Mo1-P NRs presented an onset potential of 63.2 mV, and an overpotential of 117.9 mV was required to drive the current density of 10 mA↔cm− 2. Meanwhile, The Tafel slope, exchange current density (j0), electrochemical double-layer capacitance (Cdl) were 58.6 mV↔dec− 1, 0.10 mA↔cm− 2, 12.6 mF↔cm− 2, respectively. Moreover, there was no obvious activity diminish of Ni1-Mo1-P NRs after a long-term stability and durability test.

MnOx/Ni(OH)2 Nanocomposite Materials for High-Performance Electrochemical Capacitor Application

2012 ◽  
Vol 20 ◽  
pp. 53-60 ◽  
Author(s):  
Zan Wang ◽  
Xin Wang ◽  
Yun Xiao Zhao ◽  
Cui Mei Zhao ◽  
Wei Tao Zheng
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Specific Capacitance ◽  
Discharge Process ◽  
Porous Network ◽  
X Ray ◽  
Capacitance Performance ◽  
Charge Discharge

Nanostructured MnOx/Ni (OH)2 composites have been electrodeposited on Ni foam for synthesis of a binder-free electrode for electrochemical capacitors with high specific capacitance and stable electrochemical properties. The microstructure, morphology and chemical composition were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical capacitance of the electrode active materials. The results indicated that MnOx acted as a template for growth of Ni (OH)2 with an inter-connected 3D porous network nanostructure. A maximum capacitance value of 2334 F/g at current density of 5 A/g in 1 M KOH electrolyte was achieved, much higher than that of pure Ni (OH)2 and MnOx (992 and 179 F/g, respectively). Moreover, in the charge/discharge process at even larger current density of 20 A/g, the electrode could maintain 82.8 % of the initial specific capacitance after 500 cycles, higher than that of pure Ni (OH)2 (only 46.6% remains). The enhanced capacitance performance was attributed to the synergic effect between the respective single oxides.

Surface Passivation of p-GaTe Layered Crystals for Improved p-GaTe/n-InSe Heterojunction Solar Cells

2010 ◽  
Vol 1268 ◽  
Author(s):  
Krishna C. Mandal ◽  
Sandip Das ◽  
Ramesh Krishna ◽  
Peter G. Muzykov ◽  
Shuguo Ma ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Solar Cell ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Short Circuit ◽  
Solar Cell Performance ◽  
X Ray ◽  
Heterojunction Solar Cells

AbstractGaTe and GaTe:In single crystals were grown from high purity Ga (7N) and zone refined Te (>7N) precursor materials. InSe thin films were deposited by thermal evaporation onto the sulfur passivated GaTe:In substrates at various substrate temperatures from 450K-550K to fabricate p-GaTe:In/n-InSe heterojunction solar cells. Scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and X-ray photoelectron spectroscopy (XPS) were used to characterize GaTe:In crystals and InSe thin film surfaces. The current-voltage characteristics of p-GaTe:In/n-InSe solar cells were measured under dark and under illumination of 75mW/cm2. Dark J-V measurements showed that the reverse saturation current density (J0) decreased from 3.8 x 10-6 A/cm2 to 1.5 x 10-9 A/cm2 and the ideality factor was reduced from 2.04 to 1.15 as a result of surface passivation. Under illumination of 75 mW/cm2, the open-circuit voltage (Voc) increased from 0.54V to 0.68V and short-circuit current density (Jsc) increased from 7.19 mA/cm2 to 8.65 mA/cm2 for solar cells with surface passivated GaTe:In substrates, leading to an increased solar cell efficiency of 5.03%. EPMA measurements revealed that the InSe thin films deposited at 550 K on GaTe:In substrates were near stoichiometric with enhanced grain size contributing also to better solar cell performance.

Study of corrosion behavior of virgin and recycled Pb anodes used in zinc electrowinning industry

2020 ◽  
Vol 67 (6) ◽  
pp. 529-536
Author(s):  
Shima Nakisa ◽  
Naghi Parvini Ahmadi ◽  
Javad Moghaddam ◽  
Habib Ashassi-Sorkhabi
Keyword(s):  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Electrochemical Impedance ◽  
Zinc Electrowinning ◽  
Composition Analysis ◽  
Corrosion Properties ◽  
Content Type ◽  
X Ray ◽  
Galvanostatic Polarization

Purpose The composition and corrosion behaviors of recycled and virgin Pb anode were investigated in industrial zinc electrowinning solution with different methods. The purpose of this study is the illustration of good anticorrosion activity of virgin Pb anodes compared to recycled one in industrial operation, while the compositions of both of them are the same which obtained from quantmetry method. Design/methodology/approach Its corrosion properties and electrocatalytic activity toward oxygen evolution reaction were appraised using potentiodynamic polarization, electrochemical impedance spectroscopy, galvanostatic polarization and ionic equilibrium methods. In addition, composition of anodes investigated with X-ray photoelectron spectroscopy (XPS) method. The surface composition of samples was studied via X-ray diffractogram (XRD). Findings The results indicate that the anodes display different anodic behaviors during the galvanostatic polarization. Virgin Pb anode shows a “potential reduction” about 320 mV lower than recycled Pb anode after 6 h of polarization; also, the stable potential after 72 h for virgin Pb anode is 100 mV lower than recycled Pb anode. Also, The XPS results show a trace amount of Cl in recycled anodes which cause the more corrosion activity. XRD results indicate that virgin Pb anodes have been covered by more oxides than recycled anodes after 72 h of electrowinning. Originality/value The treatment of corrosion behavior by virginity has not been detected by any researchers yet. Therefore, it is imperative to study the corrosion behavior and exact composition analysis of virgin and recycled Pb anodes to comprehension of them. This paper fulfills this need.

Hydrothermal synthesis of PANI nanowires for high-performance supercapacitor

2019 ◽  
Vol 32 (3) ◽  
pp. 258-267 ◽  
Author(s):  
Jia Chu ◽  
Xue Li ◽  
Qiaoqin Li ◽  
Jing Ma ◽  
Bohua Wu ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Scanning Electron Micrographs ◽  
X Ray ◽  
Different Temperatures ◽  
Polyaniline Nanowires ◽  
Charge Discharge

Polyaniline nanowires (PANI NWs) were synthesized under different temperatures through a facile hydrothermal method and used as electrodes for high-performance pseudocapacitor. The resulting samples were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron micrographs, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Electrochemical properties of these PANI electrodes are studied by cyclic voltammetry, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy in 0.5M H2SO4 aqueous solution. The highest specific capacitance is obtained on the PANI NWs synthesized under 80°C (PANI-80) with 540.0 F g−1 at current density of 0.5 A g−1 accompanied with 82% specific capacitance retention after 1000 charge discharge cycles at 5 A g−1 current density.

scholarly journals Enhancement of Solar Cell Performance of Electrodeposited Ti/n-Cu2O/p-Cu2O/Au Homojunction Solar Cells by Interface and Surface Modification

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 609 ◽  
Author(s):  
Charith Jayathilaka ◽  
Loku Singgappulige Rosantha Kumara ◽  
Koji Ohara ◽  
Chulho Song ◽  
Shinji Kohara ◽  
...  
Keyword(s):  
Solar Cell ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
High Energy ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
Solar Cell Performance ◽  
X Ray

Cuprous oxide (Cu2O) homojunction thin films on Ti substrates were fabricated by an electrochemical deposition in which a p-Cu2O layer was deposited on an n-Cu2O layer by carefully controlled bath conditions. It was found that the open-circuit voltage of the homojunction solar cell was significantly influenced by the pH of the lactate bath. The variation of the pH was used to achieve the best possible crystal orientation for homojunctions. The crystallinity and morphology of the products were characterized by X-ray diffraction (XRD), high-energy x-ray diffraction (HEXRD), and scanning electron microscopy (SEM). The current density voltage (J-V) analysis showed that the sulfur treatment and annealing enhanced the photocurrent by ten-fold compared to the untreated and unannealed homojunction solar cell. X-ray photoelectron spectroscopy (XPS) studies confirmed that the sulfur treatment eliminated the surface CuO and formed a thin layer of CuS, which was very useful to make the front Ohmic contact. Transient measurements confirmed that the p-type Cu2O layer, which was subjected to sulfur treatment, significantly reduced the recombination, thus enhancing the efficiency of the solar cell. The best sulfur treated annealed Ti/n-Cu2O/p-Cu2O/Au solar cell produced an energy conversion efficiency of 2.64% with an open-circuit voltage of 490 mV and a short circuit current density of 12.8 mA cm−2 under AM 1.5 illumination.

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