• Journal of Electrochemical Science and Technology
• /
• 제15권1호
• /
• pp.96-110
• /
• 2024

Polymer electrolyte membrane fuel cells (PEMFCs) are green energy conversion devices, for which commercial markets have been established, owing to their application in fuel cell vehicles (FCVs). Development of cathode electrocatalysts, replacing commercial Pt/C, plays a crucial role in factors such as cost reduction, high performance, and durability in FCVs. PtNi octahedral catalysts are promising for oxygen reduction reactions owing to their significantly higher mass activity (10-15 times) than that of Pt/C; however, their application in membrane electrode assemblies (MEAs) is challenged by their low stability. To overcome this durability issue, various approaches, such as third-metal doping, composition control, halide treatment, formation of a Pt layer, annealing treatment, and size control, have been explored and have shown promising improvements in stability in rotating disk electrode (RDE) testing. In this review, we aimed to compare the features of each strategy in terms of enhancing stability by introducing a stability improvement factor for a direct and reasonable comparison. The limitations of each strategy for enhancing stability of PtNi octahedral are also described. This review can serve as a valuable guide for the development of strategies to enhance the durability of octahedral PtNi.

• 전기화학회지
• /
• 제14권2호
• /
• pp.71-76
• /
• 2011

Fe-tetramethoxyphenylporphyrin on carbon black (Fe-TMPP/C) is examined and compared with carbon (C) and Pt-coated carbon (Pt/C) for oxygen reduction reaction in a two chambered microbial fuel cell (MFC). The Fe-TMPP/C is prepared by heat treatment and characterized using SEM, TEM, and XPS. The electrochemical properties of catalysts are characterized by voltammerty and single cell measurements. It is found that the power generation in the MFC with Fe-TMPP/C as the cathode is higher than that with Pt/C. The maximum power of the Fe-TMPP/C is 0.12 mW compared with 0.10 mW (Pt/C) and 0.02 mW (C). This high output with the Fe-TMPP/C indicates that MFCs are promising in further practical applications with low cost macrocycles catalysts.

• 전기화학회지
• /
• 제10권3호
• /
• pp.207-212
• /
• 2007

IT-SOFC(중저온형 고체산화물 연료전지)의 공기극으로 적합한 PSCF3737의 물질 특성을 파악하고 그 특성을 이용하여 낮은 ASR을 갖기 위한 소결 온도 및 두께 최적화에 관한 연구를 수행하였다. 분말 사이즈 및 상형성을 고려할 때 GNP 방법으로 합성된 분말의 하소 온도는 $1000^{\circ}C$가 적합함을 알 수 있었다. 산소 분압에 따른 ASR 변화 실험을 통하여 PSCF3737의 저항 성분을 전극 자체의 특성과 관련된 중간 주파수 대역(${\sim}10^2Hz$)과 산소의 확산에 영향 받는 낮은 주파수 대역(${\sim}10^{-1}Hz$) 2가지로 분류할 수 있었다. 공기극의 특성 실험을 통하여 소결 온도는 $1200^{\circ}C$가 가장 적합하며 공기극의 두께는 2번 스크린 프린팅 된 $27\;{\mu}m$가 가장 적합함을 알 수 있었다. 이를 토대로 EIS 측정을 하면 $700^{\circ}C$에서 $0.115\;{\Omega}cm^2$의 낮은 ASR값을 얻을 수 있었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.509-512
• /
• 2000

LCD displays for flat monitors the backlit using Cold Cathode Flourescent Lamps(CCFLs) In this paper a low-cost series resonant half-bridge inverter for LCD backlight is proposed as a CCFL ballast. It is regulated by asymmetric control for its fixed frequency soft switching model. The attractiveness of this topology is primarily its low cost because of using BJT switches and reduction of anti-parallel diode. Design procedure and experimental verification from 5W 15"LCD backlight are presented.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.252-252
• /
• 2009

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2004년도 학술대회지
• /
• pp.145-147
• /
• 2004

• 한국표면공학회지
• /
• 제8권2호
• /
• pp.1-6
• /
• 1975

A novel electroplating process is described and effects of anode lay-out thickness distribution and on platiting rate are discussed. Microphotograhic analysis indicates are compact and less "POROUS " than of barrel and rack. With this process production cost reduction and capacity increase could be achieved by a rate of 60% and 97% respectively, as compared to our present barrel plating process. This process disclose a number of beneficial processes such as color coding system on TO-92 package and development of a new tin bath formula.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.776-779
• /
• 2003

To reduce the storage space of spent fuel used at the atomic power plants in the over the world, the uranium elements contained in the spent fuel is being extracted and effectively stored. For this, the spent fuel are oxidized and deoxidized. In this study, it is produced the heat-resisting methods about the spent fuel management technology research and test facility for the spent fuel waste for spent fuel minimized. The first considered processes in the facility are the electrolytic metal reduction reactor process. Since the electrolytic metal reduction reactor is operated at the high temperature range, we have to consider the heat-resisting methods for the devices. For the heat-resisting methods, we have searched and analyzed technical reference for the heat-resisting methods. We have calculated thermal stress and strain of each devices by the commercial analysis software, ANSYS. D.S. It is experimented for inspecting confidence rate of analysis results. By using the results, we have analyzed the problems of parts and determined the heat-resisting material, commercial parts, and the size of parts and O-ring. Based on these results, it is produced the heat-resisting methods of magnesia filter, cathode, and reactor for the electrolytic metal reduction reactor.

• 한국표면공학회지
• /
• 제51권5호
• /
• pp.332-336
• /
• 2018

Alkaline oxygen electrocatalysis, targeting anion exchange membrane alkaline-based metal-air batteries has become a subject of intensive investigation because of its advantages compared to its acidic counterparts in reaction kinetics and materials stability. However, significant breakthroughs in the design and synthesis of efficient oxygen reduction catalysts from earth-abundant elements instead of precious metals in alkaline media still remain in high demand. One of the most inexpensive alternatives is carbonaceous materials, which have attracted extensive attention either as catalyst supports or as metal-free cathode catalysts for oxygen reduction. Also, carbon composite materials have been recognized as the most promising because of their reasonable balance between catalytic activity, durability, and cost. In particular, heteroatom (e.g., N, B, S or P) doping on carbon materials can tune the electronic and geometric properties of carbon, providing more active sites and enhancing the interaction between carbon structure and active sites. Here, we focused on boron and nitrogen doped nanocarbon composit (BNC nanocarbon) catalysts synthesized by a solution plasma process using the simple precursor of pyridine and boric acid without further annealing process. Additionally, guidance for rational design and synthesis of alkaline ORR catalysts with improved activity is also presented.

• 청정기술
• /
• 제7권3호
• /
• pp.215-223
• /
• 2001

A present semiconductor cleaning technology is based upon RCA cleaning technology which consumes vast amounts of chemicals and ultra pure water(UPW) and is the high temperature process. Therefore, this technology gives rise to the many environmental issues, and some alternatives such as electrolyzed water(EW) are being studied. In this work, intentionally contaminated Si wafers were cleaned using the electrolyzed water. The electrolyzed water was generated by an electrolysis system which consists of three anode, cathode, and middle chambers. Oxidative water and reductive water were obtained in anode and cathode chambers, respectively. In case of NH4Cl electrolyte, the oxidation-reduction potential and pH for anode water(AW) and cathode water(CW) were measured to be +1050mV and 4.8, and -750mV and 10.0, respectively. AW and CW were deteriorated after electrolyzed, but maintained their characteristics for more than 40 minutes sufficiently enough for cleaning. Their deterioration was correlated with CO2 concentration changes dissolved from air. Contact angles of UPW, AW, and CW on DHF treated Si wafer surfaces were measured to be $65.9^{\circ}$, $66.5^{\circ}$ and $56.8^{\circ}$, respectively, which characterizes clearly the eletrolyzed water. To analyze the amount of metallic impurities on Si wafer surface, ICP-MS was introduced. It was known that AW was effective for Cu removal, while CW was more effective for Fe removal. To analyze the number of particles on Si wafer surfaces, Tencor 6220 were introduced. The particle distributions after various particle removal processes maintained the same pattern. In this work, RCA consumed about $9{\ell}$ chemicals, while EW did only $400m{\ell}$ HCl electrolyte or $600m{\ell}$ NH4Cl electrolyte. It was hence concluded that EW cleaning technology would be very effective for promoting environment, safety, and health(ESH) issues in the next generation semiconductor manufacturing.