• Title, Summary, Keyword: Anode Oxidation

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Synthesis of Cyclitol Derivatives (Ⅲ). Electrolytic Oxidation of myo-Inositol (Cyclitol 유도체 합성에 관한 연구 (제3보)-myo-Inositol의 전해 산화-)

  • Joo Hwan Sohn;Chong Woo Nam;Yu Ok Kim
    • Journal of the Korean Chemical Society
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    • v.15 no.3
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    • pp.127-132
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    • 1971
  • To obtain the various kinds of inosose stereomers, the process of electrochemical oxidation is more effective than chemical oxidation of myo-inositol. So that myo-inositol aqueous solution was electrolyzed by platinum and lead peroxide anode to confirming the occurrence of electrochemical oxidation. The result is that myo-inosose-2 is producing with high yield comparatively by electrolytic oxidation of myo-inositol. Also we studied about the relation between the electrolytic current efficiency and electrolytic temperature and anodic current density. The current efficiency is rising with lowering of electrolytic temperature identically in both anode such as platinum and lead peroxide and also rising with increasing of anodic current density in platinum anode, but inversely in lead peroxide.

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The Research on Aluminum and Silcon Nanoparticles as Anode Materials for Lithium Ion Batteries (알루미늄 실리콘 나노분말을 이용한 리튬이온전지 음극재료에 관한 연구)

  • Kim, Hyeong-Jo;Tulugan, Kelimu;Kim, Hyung-Jin;Park, Won-Jo
    • Journal of Power System Engineering
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    • v.17 no.1
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    • pp.110-115
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    • 2013
  • The electrochemical performance and microstructure of Al-Si, Al-Si/C was investigated as anode for lithium ion battery. The Al-Si nano composite with 5 : 1 at% ratio was prepared by arc-discharge nano powder process. However, some of problem is occurred, when Al nano composite was synthesized by this manufacturing. The oxidation film is generated around Al-Si particles for passivating processing in the manufacture. The oxidation film interrupts electrical chemistry reaction during lithium ion insertion/extraction for charge and discharge. Because of the existence the oxidation film, Al-Si first cycle capacity is very lower than other examples. Therefore, carbon synthsized by glucose ($C_6H_{12}O_6$) was conducted to remove the oxidation film covered on the composite. The results showed that the first discharge cycle capacity of Al-Si/C is improved to 113mAh/g comparing with Al-Si (18.6mAh/g). Furthermore, XRD data and TEM images indicate that $Al_4C_3$ crystalline exist in Al-Si/C composite. In addition the Si-Al anode material, in which silicon is more contained was tested by same method as above, it was investigated to check the anode capacity and morphology properties in accordance with changing content of silicon, Si-Al anode has much higher initial discharge capacity(about 500mAh/g) than anode materials based on Aluminum as well as the morphology properties is also very different with the anode based Aluminum.

Effect of Oxidation of Ni on the Microstructure of Ni/YSZ Anode and Crack Formation in YSZ Electrolyte Layer for SOFC (Ni의 산화가 고체산화물 연료전지용 Ni/YSZ 연료극의 미세조직과 전해질의 균열에 미치는 영향)

  • Lim, Jun-Sil;Choi, Jong-Joon;Kwon, Oh-Jong
    • Journal of the Korean Ceramic Society
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    • v.43 no.12
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    • pp.805-811
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    • 2006
  • The microstructural changes in Ni/YSZ anode substrate and crack formation during Ni oxidation were investigated. The composition of as-sintered anodes was 56 wt% NiO+44 wt% YSZ and that of electrolyte was 8 mol% yttria. After complete reduction, specimens were oxidized in $N_2$ + air at $600\sim800^{\circ}C$. Oxygen partial pressure was controlled in between 0.05 atm and 0.2 atm $O_2$. When the anode was oxidized, at higher than $690^{\circ}C$, three layers were formed in the specimens. The first was fully oxidized layer(NiO/YSZ), the second was a mixed layer and the third, near-intact layer. Under $640^{\circ}C$ such distinctive layers were not observed. Cracks formed at electrolyte layer when weight gain attained at $65\sim75%$ of the total gain due to complete oxidation despite of different oxidation temperature and oxygen partial pressure.

Competitive electrochemical oxidation of reformate gas in SOFCs (고체 산화물 연료전지 음극에서 개질 가스의 경쟁적 전기화학 반응)

  • Kim, Yong-Min;Bae, Joong-Myeon;Bae, Gyu-Jong;Kim, Jung-Hyun;Lee, Chang-Bo
    • 한국신재생에너지학회:학술대회논문집
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    • pp.5-8
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    • 2008
  • SOFC (Solid oxide fuel cell) has an advantage in the term of fuel flexibility, comparing with other kinds of fuel cells. In SOFC and fuel reformer cooperation system, the reformate gas with the various $H_2$/CO ratios is delivered into the anode of SOFC. In this situation, electrochemical oxidation reactions of the reformate gas in the anode are complex and competitive. In this paper, the effects of the composition of $H_2$ and CO on the overall electrochemical oxidation at Ni-YSZ anode are studied by testing the open circuit voltage (OCV) and current-voltage characteristics of single cells.

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Self-Regeneration of Intelligent Perovskite Oxide Anode for Direct Hydrocarbon-Type SOFC by Nano Metal Particles of Pd Segregated (Pd 나노입자의 자가 회복이 가능한 지능형 페로브스카이트 산화물 음극의 직접 탄화수소계 SOFC 성능 평가)

  • Oh, Mi Young;Ishihara, Tatsumi;Shin, Tae Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.5
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    • pp.345-350
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    • 2018
  • Nanomaterials have considerable potential to solve several key challenges in various electrochemical devices, such as fuel cells. However, the use of nanoparticles in high-temperature devices like solid-oxide fuel cells (SOFCs) is considered problematic because the nanostructured surface typically prepared by deposition techniques may easily coarsen and thus deactivate, especially when used in high-temperature redox conditions. Herein we report the synthesis of a self-regenerated Pd metal nanoparticle on the perovskite oxide anode surface for SOFCs that exhibit self-recovery from their degradation in redox cycle and $CH_4$ fuel running. Using Pd-doped perovskite, $La(Sr)Fe(Mn,Pd)O_3$, as an anode, fairly high maximum power densities of 0.5 and $0.2cm^{-2}$ were achieved at 1,073 K in $H_2$ and $CH_4$ respectively, despite using thick electrolyte support-type cell. Long-term stability was also examined in $CH_4$ and the redox cycle, when the anode is exposed to air. The cell with Pd-doped perovskite anode had high tolerance against re-oxidation and recovered the behavior of anodic performance from catalytic degradation. This recovery of power density can be explained by the surface segregation of Pd nanoparticles, which are self-recovered via re-oxidation and reduction. In addition, self-recovery of the anode by oxidation treatment was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

A Study on environmental-friendly Cleaning for Si-wafers (환경친화적인 실리콘 웨이퍼 세정 연구)

  • Yoon, Hyoseob;Ryoo, Kunkul
    • Clean Technology
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    • v.6 no.1
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    • pp.79-84
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    • 2000
  • In this study, to reduce the consumption of chemicals in cleaning processes, Si-wafers contaiminated with metallic impurities were cleaned with electrolyzed water(EW), which was generated by the electrolysis of a diluted electrolyte solution or ultra pure water(UPW). Electrolyzed water could be controlled for obtaining wide ranges of pH and ORP(oxidation-reduction potential). The pH and oxidation-reduction potential of anode water and cathode water were measured to be 4.7 and +1000mV, and 6.3 and -550mV, respectively. To analyze the amount of metallic impurities on Si-wafer surfaces, ICP-MS was introduced. Anode water was effective for Cu removal, while cathode water was more effective for Fe removal.

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Effect of Electrochemical Oxidation Potential on Biofilter for Bacteriological Oxidation of VOCs to $CO_2$

  • Kang Hye-Sun;Lee Jong-Kwang;Kim Moo-Hoon;Park Doo-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.16 no.3
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    • pp.399-407
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    • 2006
  • In this study, an electrical conductive carbon fiber was used as a biofilter matrix to electrochemically improve the biofilter function. A bioreactor system was composed of carbon fiber (anode), titanium ring, porcelain ring, inorganic nutrient reservoir, and VOC reservoir. Electric DC power of 1.5 volt was charged to the carbon fiber anode (CFA) to induce the electrochemical oxidation potential on the biofilter matrix, but not to the carbon fiber (CF). We tested the effects of electrochemical oxidation potential charged to the CFA on the biofilm structure, the bacterial growth, and the activity for metabolic oxidation of VOCs to $CO_2$, According to the SEM image, the biofilm structure developed in the CFA appeared to be greatly different from that in the CF. The bacterial growth, VOCs degradation, and metabolic oxidation of VOCs to $CO_2$ in the CFA were more activated than those in the CF. On the basis of these results, we propose that the biofilm structure can be improved, and the bacterial growth and the bacterial oxidation activity of VOCs can be activated by the electrochemical oxidation potential charged to a biofilter matrix.

Influence of Temperature on the Electrolytic Oxidation of Sulphate Solutions by Electro-deposited Lead Peroxide Anode (전착과산화납양극에 의한 황산염. 전해산화시의 전해온도의 영향)

  • Chong Woo Nam;Hak Joon Kim
    • Journal of the Korean Chemical Society
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    • v.15 no.5
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    • pp.223-228
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    • 1971
  • In the electrolytic preparation of persulphate from sulphate solution, the current efficiency decrease with temperature increase at the platinum anode. But in case of electrodeposited lead peroxide anode, the current efficiency increase with temperature of the solution. The reason seems to be that the ozone formation is faster in platinum anode than in lead peroxide as temperature increase.

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A Study on the Oxidation Characteristics of p-Cresol on Pt Anode (백금전극(白金電極)에 의한 파라크레졸의 양극전해(陽極電解) 산화특성(酸化特性))

  • Kim, Hong-Soo;Nam, Jeong-Woo
    • Journal of the Korean Applied Science and Technology
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    • v.7 no.2
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    • pp.47-53
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    • 1990
  • The electrochemical oxidation behavior of p-cresol on platinum anode had been investigated by cyclic voltammetric method for the variation of concentration, scan rate of potential, temperature and pH of electrolyte. The oxidation potential of p-cresol was dependent on the electrolyte until the pH=11.5, but in basic solution over its, it was held at o.40V(vs. SCE). A diffusion was rate determining step of oxidation as irreversible reaction by the transfer atone electron. The current of peak was proportional to concentration of p-cresol until the 0.1N and optimum concentration was found to be about 0.1N. The activation energy was calculated for 5.8kcal/mol from the plot of log $I_l$ vs. 1/T.

A study on the oxidation characteristics of phenol on Pt anode (백금전극을 이용한 페놀의 산화특성에 관한 연구)

  • Kim, Hong-Soo;Nam, Jeong-Woo;Nam, Ki-Dae
    • Applied Chemistry for Engineering
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    • v.1 no.1
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    • pp.44-51
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    • 1990
  • The electrochemical oxidation behavior of phenol on platinum anode had been investigated by cyclic voltammetric method. The initial oxidation potential of phenol was dependent on the pH in acid solution. But in basic solution, it was held 033-0.40V(vs. S.C.E.). The peak current was proportional to the concentration of phenol and the optimum concentration was found to be about 0.1N. The oxidation reaction of phenol was found to be irreversible and controlled by diffusion.

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