• Analytical Science and Technology
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• 제5권1호
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• pp.7-15
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• 1992

Germainium(IV) was determined in perchloate supporting electrolyte solution containing phenylfluorone by hanging mercury drop electrode(HMDE) of Linear Sweep Voltammetry(LSV) and in hydrochloric acid solution by UV-VIS Spectrophotometry. The complex germanium(IV) with phenylfluorone was shown linear calibration curve in the range of $2.5{\sim}80{\mu}g/L$ by LSV and in the range of $10{\sim}300{\mu}g/L$ by UV-VIS Spectrophotometry.

• Korean Chemical Engineering Research
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• 제56권2호
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• pp.151-155
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• 2018

Degree of membrane degradation in Proton Exchange Membrane Fuel Cells (PEMFC) is mainly evaluated by the hydrogen crossover current density. The hydrogen crossover current density is measured by linear sweep voltammetry (LSV), which differs from the DOE protocol and the NEDO protocol. In this study, two protocols were compared during PEMFC operation and accelerated stress test. In the LSV method by the DOE method, the scan rate change affects the hydrogen crossover current density, but the NEDO method does not affect the hydrogen crossover current density. In the course of 15,000 cycles of polymer membrane wet/dry cycle, the DOE method was sensitive to membrane degradation, but the NEDO method was less sensitive to membrane degradation than the DOE method.

• Korean Chemical Engineering Research
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• 제57권4호
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• pp.507-511
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• 2019

Hydrogen permeability is widely used to evaluate the polymer membrane durability of polymer electrolyte fuel cells (PEMFC). Linear sweep voltammetry (LSV) is mainly used to measure hydrogen permeability easily. There are many differences in LSV measurement method among researchers, and it is often difficult to compare the results. Therefore, in this study, we tried to confirm the accuracy by comparing the hydrogen permeability of LSV method and gas chromatograph which is difficult to measure but accurate value. The LSV method used the DOE and NEDO methods. When the hydrogen permeability was measured by varying the temperature and the relative humidity, the DOE LSV method showed an accuracy of less than 5% in the error range compared with the GC method. In the NEDO LSV method, the error was reduced when the hydrogen permeation current density was determined at the current value of 0.3 V as the DOE method.

• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.379-383
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• 2020

The novel voltammetry using a semi-circular potential wave for quasi-reversible charge transfer system on electrode is theoretically investigated. Compared with conventional voltammetry based on linear sweep such as linear sweep voltammetry (LSV), semi-circular potential sweep voltammetry (SCV) may decrease the charging current outside the center of potential range and increase the faradaic current at the midpoint due to variable scan rate. In this paper, we investigate the system based on macroelectrode where simple 1 dimensional (1 D) diffusion system is valid with various charge transfer rate constant (k₀). In order to observe the amplification at midpoint, voltammetric response with different midpoint ranging from -200 mV to 200 mV are studied. SCVs shows both the shift of peak potential and the amplification of peak current for quasi-reversible electrode reaction while only higher peak current is observed for reversible reaction. Moreover, the higher current at midpoint enable the amplification of current at low overpotential region which may assist the determination of onset potential as a figure-of-merit in electrocatalyst.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.123-123
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• 2008

본 논문에서는 Cu의 ECMP 적용을 위해 $HNO_3$ 전해액의 active, passive, transient, trans-passive 영역을 I-V 특성 곡선을 통해 알아보았고, LSV (Linear sweep voltammetry)와 CV (Cyclic voltammetry)법을 통하여 전기화학적 특성을 비교 분석하였다.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2290-2295
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• 2018

An acceleration stress test (AST) was performed to evaluate the durability of a polymer membrane in a polymer electrolyte membrane fuel cell (PEMFC) for 500 hours. Previous studies have shown that hydrogen crossover measured by linear sweep voltammetry (LSV) increases when the polymer membrane deteriorates in the AST process. On the other hand, hydrogen crossover of the membrane often decreases in the early stages of the AST test. To investigate the cause of this phenomenon, we analyzed the MEA operated for 50 hours using the AST method (OCV, RH 30% and $90^{\circ}C$). Cyclic voltammetry and transmission electron showed that the electrochemical surface area (ECSA) decreased due to the growth of electrode catalyst particles and that the hydrogen crossover current density measured by LSV could be reduced. Fourier transform infrared spectroscopy and thermogravimetric/differential thermal analysis showed that -S-O-S- crosslinking occurred in the polymer after the 50 hour AST. Gas chromatography showed that the hydrogen permeability was decreased by -S-O-S- crosslinking. The reduction of the hydrogen crossover current density measured by LSV in the early stages of AST could be caused by both reduction of the electrochemical surface area of the electrode catalyst and -S-O-S- crosslinking.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.486-486
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• 2009

In this paper, the current-voltage (I-V) curves, such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV), were employed to evaluate the effect of electrolyte concentration on the electrochemical reaction trend. From the I-V curve, the electrochemical states of active, passive, transient and trans-passive could be characterized. And then, we investigated that how this chemical affect the process of voltage-induced material removal in electrochemical mechanical polishing (ECMP) of Copper. The scanning electron microscopy (SEM) and energy dispersive spectroscopy EDS) analyses were used to observe the surface profile. Finally, we monitored the oxidation and reduction process of the Cu surface by the repetition of anodic and cathodic potential from cyclic voltammetry (CV) method in acid- and alkali-based electrolyte. From these analyses, it was important to understand the electrochemical mechanisms of the ECMP technology.

• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.346-351
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• 2020

The removal characteristics of copper (Cu) from electrochemical surface by voltage-activated reaction were reviewed to assess the applicability of electrochemical-mechanical polishing (ECMP) process in three types of electrolytes, such as HNO₃, KNO₃ and NaNO₃. Electrochemical surface conditions such as active, passive, transient and trans-passive states were monitored from its current-voltage (I-V) characteristic curves obtained by linear sweep voltammetry (LSV) method. In addition, the oxidation and reduction process of the Cu surface by repetitive input of positive and negative voltages were evaluated from the I-V curve obtained using the cyclic voltammetry (CV) method. Finally, the X-ray diffraction (XRD) patterns and energy dispersive spectroscopy (EDS) analyses were used to observe the structural surface states of a Cu electrode. The electrochemical analyses proposed in this study will help to accurately control the material removal rate (MRR) from the actual ECMP process because they are a good methodology for predicting optimal electrochemical process parameters such as current density, operating voltage, and operating time before performing the ECMP process.

• Korean Chemical Engineering Research
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• 제52권4호
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• pp.425-429
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• 2014

Until a recent day, degradation of PEMFC MEA(membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. Hydrogen permeability was used often to measure degradation of electrolyte membrane in PEMFC. In case of hydrogen permeability measured by LSV(Linear Sweep Voltammetry) method, the degradation of electrode decrease the value of hydrogen crossover current due to LSV methode's dependence on electrode active area. In this study hydrogen permeability was measured by gas chromatograph(GC) when membrane and electrode degraded at the same time. It was showed that degradation of electrode did not affect the hydrogen permeability measured by GC because of GC methode's independence on electrode active area.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1462-1466
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• 2013

We demonstrate that ruthenium oxide ($RuO_2$) nanotubes with controlled dimensions can be synthesized using facile electrochemical means and anodic aluminum oxide (AAO) templates. $RuO_2$ nanotubes were formed using a cyclic voltammetric deposition technique and an aqueous plating solution composed of $RuCl_3$. Linear sweep voltammetry (LSV) was used to determine the effective electrochemical oxidation potential of $Ru^{3+}$ to $RuO_2$. The length and wall thickness of $RuO_2$ nanotubes can be adjusted by varying the range and cycles of the electrochemical cyclic voltammetric potentials. Thick-walled $RuO_2$ nanotubes were obtained using a wide electrochemical potential range (-0.2~1 V). In contrast, an electrochemical deposition potential range from 0.8 to 1 V produced thin-walled and longer $RuO_2$ nanotubes in an identical number of cycles. The dependence of wall thickness and length of $RuO_2$ nanotubes on the range of cyclic voltammetric electrochemical potentials was attributed to the distinct ionic diffusion times. This significantly improves the ratio of surface area to mass of materials synthesized using AAO templates. Furthermore, this study is directive to the controlled synthesis of other metal oxide nanotubes using a similar strategy.