LiCl-KCl 용융염에서 광학적으로 투명한 전극을 이용한 사마륨 이온의 전기화학적 거동에 관한 연구

Ae-Ri Lee,Byung Gi Park 한국방사성폐기물학회 2017 방사성폐기물학회지 Vol.15 No.4

LiCl-KCl 용융염에서 광학적으로 투명한 텅스텐 망으로 제작된 작업전극에 대해 사마륨의 전기화학적 거동을 Cyclic voltammetry와 Potential step chronoabsorptometry의 전기화학적 및 분광전기화학적 방법으로 조사하였다. Cyclic voltammogram 으로 결정된 Sm3+/Sm2+의 산화환원 반응의 가역성을 기반으로 형식전위와 확산계수를 계산하여 각각 –1.99 V vs. Cl2/Cl- 와 2.53×10-6 cm2·s-1를 얻었다. 작업 전극에 –1.5 V vs. Ag/AgCl (wt%)로 전압을 인가하여 측정한 Chronoabsorptometry 를 통해 사마륨 이온의 특성 파장으로 Sm3+에 대해 408.08 nm, Sm2+에 대해 545.62 nm를 확인하였다. Voltammogram에서 얻은 환원 피크 전압과 산화 피크 전압을 이용하여 Potential step chronoabsorptometry를 수행하였다. 545.63 nm의 흡광 피크 값을 분석하여 2.15×10-6 cm2·s-1의 확산계수를 얻었으며 이 값은 동일한 온도에서 Cyclic voltammtry 분석으로 얻은 값과 큰 차이를 보이지 않았다. 실험결과로부터 고온 용융염에서 광학적으로 투명한 작업전극을 이용한 분광전기화학적 방 법이 용융염에 용해된 이온의 종류를 확인하며 전기화학적 거동을 조사하는데 유용한 도구로 활용될 수 있음을 확인하였다. A spectroelectrochemical method has been applied to investigate the electrochemical behaviors and identify the kinds of samarium ions dissolved in high temperature molten LiCl-KCl eutectic. An optically transparent electrode (OTE) fabricated with a tungsten gauze as a working electrode has been used to conduct cyclic voltammetry and potential step chronoabsorptometry. Based on the reversibility of the redox reaction of Sm3+/Sm2+ , which was determined from the cyclic voltammograms, the formal potential and the diffusion coefficient were calculated to be -1.99 V vs. Cl2/Cl- and 2.53 × 10-6 cm2·s-1, respectively. From the chronoabsorptometry results at the applied potential of -1.5 V vs. Ag/AgCl (1wt%), the characteristic peaks of absorption for samarium ions were determined to be 408.08 nm for Sm3+ and 545.62 nm for Sm2+. Potential step chronoabsorptometry was conducted using the anodic and the cathodic peak potentials from the voltammograms. Absorbance analysis at 545.63 nm shows that the diffusion coefficient of Sm3+ is 2.15 × 10-6 cm2·s-1, which is comparable to the value determined by cyclic voltammetry at the same temperature.

A Study on Electrochemical Behaviors of Samarium Ions in the Molten LiCl-KCl Eutectic Using Optically Transparent Electrode

Ae-Ri Lee,Byung Gi Park 한국방사성폐기물학회 2017 방사성폐기물학회지 Vol.15 No.4

LiCl-KCl 용융염에서 광학적으로 투명한 텅스텐 망으로 제작된 작업전극에 대해 사마륨의 전기화학적 거동을 Cyclic voltammetry와 Potential step chronoabsorptometry의 전기화학적 및 분광전기화학적 방법으로 조사하였다. Cyclic voltammogram 으로 결정된 Sm3+/Sm2+의 산화환원 반응의 가역성을 기반으로 형식전위와 확산계수를 계산하여 각각 –1.99 V vs. Cl2/Cl- 와 2.53×10-6 cm2·s-1를 얻었다. 작업 전극에 –1.5 V vs. Ag/AgCl (wt%)로 전압을 인가하여 측정한 Chronoabsorptometry 를 통해 사마륨 이온의 특성 파장으로 Sm3+에 대해 408.08 nm, Sm2+에 대해 545.62 nm를 확인하였다. Voltammogram에서 얻은 환원 피크 전압과 산화 피크 전압을 이용하여 Potential step chronoabsorptometry를 수행하였다. 545.63 nm의 흡광 피크 값을 분석하여 2.15×10-6 cm2·s-1의 확산계수를 얻었으며 이 값은 동일한 온도에서 Cyclic voltammtry 분석으로 얻은 값과 큰 차이를 보이지 않았다. 실험결과로부터 고온 용융염에서 광학적으로 투명한 작업전극을 이용한 분광전기화학적 방 법이 용융염에 용해된 이온의 종류를 확인하며 전기화학적 거동을 조사하는데 유용한 도구로 활용될 수 있음을 확인하였다. A spectroelectrochemical method has been applied to investigate the electrochemical behaviors and identify the kinds of samarium ions dissolved in high temperature molten LiCl-KCl eutectic. An optically transparent electrode (OTE) fabricated with a tungsten gauze as a working electrode has been used to conduct cyclic voltammetry and potential step chronoabsorptometry. Based on the reversibility of the redox reaction of Sm3+/Sm2+ , which was determined from the cyclic voltammograms, the formal potential and the diffusion coefficient were calculated to be -1.99 V vs. Cl2/Cl- and 2.53 × 10-6 cm2·s-1, respectively. From the chronoabsorptometry results at the applied potential of -1.5 V vs. Ag/AgCl (1wt%), the characteristic peaks of absorption for samarium ions were determined to be 408.08 nm for Sm3+ and 545.62 nm for Sm2+. Potential step chronoabsorptometry was conducted using the anodic and the cathodic peak potentials from the voltammograms. Absorbance analysis at 545.63 nm shows that the diffusion coefficient of Sm3+ is 2.15 × 10-6 cm2·s-1, which is comparable to the value determined by cyclic voltammetry at the same temperature.

Cyclic Voltammetry를 이용한 CuInSe₂ 박막의 전기화학적 전착 연구

홍순현,이현주,김양도,Hong, Soonhyun,Lee, Hyunju,Kim, Yangdo 한국재료학회 2013 한국재료학회지 Vol.23 No.11

Chalcopyrite $CuInSe_2$(CIS) is considered to be an effective light-absorbing material for thin film photovoltaic solar cells. CIS thin films have been electrodeposited onto Mo coated and ITO glass substrates in potentiostatic mode at room temperature. The deposition mechanism of CIS thin films has been studied using the cyclic voltammetry (CV) technique. A cyclic voltammetric study was performed in unitary Cu, In, and Se systems, binary Cu-Se and In-Se systems, and a ternary Cu-In-Se system. The reduction peaks of the ITO substrate were examined in separate $Cu^{2+}$, $In^{3+}$, and $Se^{4+}$ solutions. Electrodeposition experiments were conducted with varying deposition potentials and electrolyte bath conditions. The morphological and compositional properties of the CIS thin films were examined by field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). The surface morphology of as-deposited CIS films exhibits spherical and large-sized clusters. The deposition potential has a significant effect on the film morphology and/or grain size, such that the structure tended to grow according to the increase of the deposition potential. A CIS layer deposited at -0.6 V nearly approached the stoichiometric ratio of $CuIn_{0.8}Se_{1.8}$. The growth potential plays an important role in controlling the stoichiometry of CIS films.

Electrochemical characterization of CdSe and CdTe thin films using cyclic voltammetry

Kim, S.H.,Han, W.K.,Lee, J.H. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.3

The electrodeposition of cadmium selenide and cadmium telluride on gold electrodes from acidic aqueous electrolyte bath have been studied using electrochemical analysis. Conventional cyclic voltammetry is considered as a reliable method to study electrochemical behavior of electrodeposition of CdSe and CdTe. The mechanism of CdSe and CdTe deposition were investigated using cyclic voltammetry. The effects of ion concentration and potential on Se and Te cyclic voltammogram were investigated. The optimum condition for CdSe and CdTe were deduced from electrochemical analysis of cyclic voltammograms.

Semi-Circular Potential Sweep Voltammetry: Electrochemically Quasi-Reversible System

Park, Kyungsoon,Hwang, Seongpil The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.4

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.

Electrochemical characterization of CdSe and CdTe thin films using cyclic voltammetry

Seong-Hun Kim,Jae-Ho Lee,Wone-Keun Han 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The electrodeposition of cadmium selenide and cadmium telluride on gold electrodes from acidic aqueous electrolyte bath have been studied using electrochemical analysis. Conventional cyclic voltammetry is considered as a reliable method to study electrochemical behavior of electrodeposition of CdSe and CdTe. The mechanism of CdSe and CdTe deposition were investigated using cyclic voltammetry. The effects of ion concentration and potential on Se and Te cyclic voltammogram were investigated. The optimum condition for CdSe and CdTe were deduced from electrochemical analysis of cyclic voltammograms.

Measurement of Critical Micelle Concentration (CMC) by Cyclic Voltammetry: CMCs for Sodium Dodecyl Sulfate Solution with Compounds Having Pyridine

고영춘 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

Poly(o-anisidine) coatings on brass: Synthesis, characterization and corrosion protection

Sudeshna Chaudhari,A.B. Gaikwad,P.P. Patil 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Poly(o-anisidine) (POA) coatings were synthesized on brass by electrochemical polymerization of o-anisidine in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The corrosion protection aspects of POA coatings on brass in aqueous 3% NaCl solution were investigated by potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the POA coating has ability to protect the brass against corrosion. The corrosion potential was about 0.204 V versus SCE more positive for the POA coated brass than that of uncoated brass and reduces the corrosion rate of brass almost by a factor of 800. The corrosion behavior of the POA coatings was also investigated by EIS through immersion tests performed in aqueous 3% NaCl solution. The evolution of the impedance parameters with the immersion time was studied and the results show that the POA acts as a protective coating on brass against corrosion in 3% NaCl solution. The water uptake and delamination area were also determined to further support the corrosion protection performance of the POA coating. Poly(o-anisidine) (POA) coatings were synthesized on brass by electrochemical polymerization of o-anisidine in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The corrosion protection aspects of POA coatings on brass in aqueous 3% NaCl solution were investigated by potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the POA coating has ability to protect the brass against corrosion. The corrosion potential was about 0.204 V versus SCE more positive for the POA coated brass than that of uncoated brass and reduces the corrosion rate of brass almost by a factor of 800. The corrosion behavior of the POA coatings was also investigated by EIS through immersion tests performed in aqueous 3% NaCl solution. The evolution of the impedance parameters with the immersion time was studied and the results show that the POA acts as a protective coating on brass against corrosion in 3% NaCl solution. The water uptake and delamination area were also determined to further support the corrosion protection performance of the POA coating.

Photocatalytic activities of contaminants by Bi₂WO₆-graphene composites decorated with mesoporous silica

Nguyen, Dinh Cung Tien,Cho, Kwang Youn,Jung, Chong-Hun,Oh, Won-Chun Elsevier 2018 Journal of alloys and compounds Vol.766 No.-

<P><B>Abstract</B></P> <P>This work reports a self-assembly method for preparing a composite of Bi<SUB>2</SUB>WO<SUB>6</SUB>-graphene and ordered mesoporous to form a novel ternary SiO<SUB>2</SUB>/Bi<SUB>2</SUB>WO<SUB>6</SUB>-graphene material. The successful synthesis was confirmed by physical tests such as XRD, SEM, TEM, EDX, XPS, DRS, Raman, and Galvano cyclic voltammetry. Moreover, the mesoporous structure of the obtained material was demonstrated by nitrogen adsorption/desorption isotherms. The investigations imply that the Bi<SUB>2</SUB>WO<SUB>6</SUB>-graphene composite was grown on an ordered mesoporous structure of the silica in a basic medium and the structure was modified with a cetyltrimethylammonium bromide surfactant. The photocatalytic activity was investigated in terms of photodegradation of cationic-anionic organic dye groups and the photocatalytic performance of gallic acid under visible light irradiation. The achieved results showed that the ternary SiO<SUB>2</SUB>/Bi<SUB>2</SUB>WO<SUB>6</SUB> catalyst holds promise to become a new potential photocatalyst for the enhancement of photocatalytic activities.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Bi<SUB>2</SUB>WO<SUB>6</SUB>-graphene composite was successfully grown on an ordered mesoporous structure of the silica. </LI> <LI> The degradation of MB at a pH of 11 in the presence of SiO<SUB>2</SUB>/Bi<SUB>2</SUB>WO<SUB>6</SUB>-graphene achieved the best photodegradation efficiency. </LI> <LI> The catalytic performance had a good result for the gallic acid degradation with 0.05 g photocatalyst. </LI> <LI> The ternary catalyst holds promise to become a new potential photocatalyst for the enhancement of photodegradation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

용융염 LiCl-KCl 내 포함된 LaCl3의 전기화학적 거동 특성

김범규,박병기,이애리,김용일,정다운 순천향대학교 부설 산업기술연구소 2013 순천향 산업기술연구소논문집 Vol.19 No.1

Most of the Uranium and Tranceuranium(TRU) elements are recovered by spent-fuels-pyroprocess which is using electrorefining and electrowinning. The components of occured molten salt waste mainly consist of Actinide(Ac) elements and Lanthanide(Ln) elements. To lower radio-activity levels of the waste by excluding uranium and TRU elements, physicochemical behavior on Ac and Ln elements is required a priori. In this study, we conducted electrochemical measurements with LaCl3 solution in LiCl-KCl. For collection of the physicochemical data, cyclic-voltammetry and chronopotentiometry methods were used. We compared those diffusion coefficient values.