• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.03a
• /
• pp.123-134
• /
• 2004

연로로부터 화학에너지를 직접 전기에너지로 바꾸는 연료전지(Fuel Cells)중 고체형 고분자 전해질 연료전지(Polymer Electrolyte Membrane Fuel Cell: PEMFC)와 직접 메탄올 연료전지(Direct Methanol Fuel Cell: DMFC)는 효율이 높고, zero emission 가능성으로 차세대 수송용 전원으로 각광받고 있는 미래 환경친화적 에너지원이다. 수소와 산소(또는 공기)와의 반응을 이용한 것이 PEMFC이고, 수소를 연료로 쓰지 않고 액체상 메탄올을 직접 연료로 사용하는 것이 DMFC이다. (중략)

• Proceeding of EDISON Challenge
• /
• 2015.03a
• /
• pp.308-311
• /
• 2015

https://nano.edison.re.kr/에서 제공하는 Linear Combination of Atomic Orbitals 기반 Density Functional Theory 전자구조계산 SW을 이용하여 정렬된 FCC 결정구조의 PtFe와 원자의 배열이 무질서한 PtFe의 산소 발생 반응의 과전압을 알아보았다. 화학 반응에 참여하는 정렬된 FCC PtFe의 표면 방위는 표면 에너지 계산을 통해 (111) 면으로 설정하였다. 과전압 값은 산소 발생 반응의 각 단계의 자유 에너지 변화를 계산하여 양의 반응 에너지이다. 과전압 측정 결과 정렬된 FCC 결정구조의 PtFe와 원자의 배열이 무질서한 PtFe의 과전압은 각 각 0.623875eV, 0.603118eV 이다.

• Korean Journal of Metals and Materials
• /
• v.47 no.7
• /
• pp.454-459
• /
• 2009

In order to commercialize Polymer Electrolyte Fuel Cell (PEFC), the cathode catalyst such as Platinum supported Carbon (Pt/C) need to have a high activity of Oxygen Reduction Reaction (ORR). In this study, the 20% Pt/C was synthesized using the chemical reduction method while the crystallinity of Platinum (Pt) particles were controlled under heat treatment conditions. The activity of synthesized Pt catalysts was evaluated using electrochemical measurement. Compared with the $i_{ORR}$ at 0.8 V of 20% Pt/C heat-treated at $500^{\circ}C$ and the 20% Pt/C that were not heated and commercial 20% Pt/C, the $i_{ORR}$ at 0.8 V of 20% Pt/C heattreated at $500^{\circ}C$ was 9.5 and 1.7 times higher than those of the 20% Pt/C and commercial 20% Pt/C that were not heated. It was considered that the crystallinity and particle size affect the ORR activity of the Pt/C catalysts.

• Journal of the Semiconductor & Display Technology
• /
• v.17 no.4
• /
• pp.1-5
• /
• 2018

Atomic force microscopy (AFM) simulation for Si (001) surface defects was conducted by using density functional theory (DFT). Three major defects on the Si (001) surface are difficult to analyze due to external noises that are always present in the images obtained by AFM. Noise-free surface defects obtained by simulation can help identify the real surface defects on AFM images. The surface defects were first optimized by using a DFT code. The AFM tip was designed by using five carbon atoms and positioned on the surface to calculate the system's energy. Forces between tip and surface were calculated from the energy data and converted into an AFM image. The simulated AFM images are noise-free and, therefore, can help evaluate the real surface defects present on the measured AFM images.

• Membrane Journal
• /
• v.32 no.2
• /
• pp.109-115
• /
• 2022

In this work, the effect of nonwoven support during fabrication of flat sheet membranes via nonsolvent-induced phase separation, was investigated in detail. It was found that dope solutions with low viscosity tend to penetrate through the nonwoven support during phase inversion, resulting in nonhomogeneous membranes. A simple soaking treatment of nonwoven support prevented such unwanted dope penetration, and resulted in membranes with higher water and solvent permeance performance. The dope penetration through nonwoven was more prominent in solutions with low viscosity, and the nonwoven soaking treatment not effective in solutions with high viscosity.

• Journal of the Korean Electrochemical Society
• /
• v.22 no.1
• /
• pp.1-12
• /
• 2019

The reduction of nitrogen to produce ammonia has been attracting much attention as a renewable energy technology. Ammonia is the basis for many fertilizers and is also considered an energy carrier that can power internal combustion engines, diesel engines, gas turbines, and fuel cells. Traditionally, ammonia has been produced through the Haber-Bosch process, in which atmospheric nitrogen combines with hydrogen at high temperature ($350-550^{\circ}C$) and high pressure (150-300 bar). This process consumes 1-2% of current global energy production and relies on fossil fuels as an energy source. Reducing the energy input required for this process will reduce $CO_2$ emissions and the corresponding environmental impact. For this reason, developing electrochemical ammonia-production methods under ambient temperature and pressure conditions should significantly reduce the energy input required to produce ammonia. In this review, we introduce the electrochemical nitrogen reduction reaction at ambient condition. Numerical studies on the electrochemical nitrogen reduction mechanism have been carried out through the computation of density function theory. Electrodes such as nanowires and porous electrodes have been also actively studied for further participation in electrochemical reactions.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
• /
• v.55 no.6
• /
• pp.670-687
• /
• 2018

This paper reviews the structures, physical and chemical properties, origins and global distribution, amount of energy resources, production technologies, and environmental impacts of gas hydrates to understand the gas hydrates as future energy sources. Hydrate structures should be studied to clarify the fundamentals of natural gas hydrates, hydrate distributions, and amount of energy sources in hydrates. Phase equilibria, dissociation enthalpy, thermal conductivity, specific heat, thermal diffusivity, and fluid permeability of gas hydrate systems are important parameters for the the efficient recovery of natural gas from hydrate reservoirs. Depressurization, thermal stimulation, inhibitor injection, and chemical exchange methods can be considered as future technologies to recover the energy sources from natural gas hydrates, but so far depressurization is the only method to have been applied in test productions of both onshore and offshore hydrates. Finally, we discuss the hypotheses of environmental impacts of gas hydrates and their contribution to global warming due to hydrate dissociation.

• Journal of the Korean institute of surface engineering
• /
• v.56 no.6
• /
• pp.437-442
• /
• 2023

This research aims to enhance the efficiency of Pt/C catalysts due to the limited availability and high cost of platinum in contemporary fuel cell catalysts. Nano-sized platinum particles were distributed onto a carbon-based support via the polyol process, utilizing the metal precursor H₂PtCl₆·6H₂O. Key parameters such as pH, temperature, and RPM were carefully regulated. The findings revealed variations in the particle size, distribution, and dispersion of nano-sized Pt particles, influenced by temperature and pH. Following sodium hydroxide treatment, heat treatment procedures were systematically executed at diverse temperatures, specifically 120, 140, and 160 ℃. Notably, the thermal treatment at 140 ℃ facilitated the production of Pt/C catalysts characterized by the smallest platinum particle size, measuring at 1.49 nm. Comparative evaluations between the commercially available Pt/C catalysts and those synthesized in this study were meticulously conducted through cyclic voltammetry, X-ray diffraction (XRD), and field-emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM EDS) methodologies. The catalyst synthesized at 160 ℃ demonstrated superior electrochemical performance; however, it is imperative to underscore the necessity for further optimization studies to refine its efficacy.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11a
• /
• pp.483-487
• /
• 2010

본 연구는 기후변화협약 대응을 위한 울산광역시 사례로 화학 산업의 온실가스 인벤토리 구축 및 공정진단을 통해 온실가스 배출 저감 결과를 나타내었다. 또한 기업체의 기후변화 대응에 대한 방향을 제시하였다. 울산지역은 산업단지 중심으로 석유화학, 자동차, 조선 등 에너지 다소비업체가 많으며, 이산화탄소 배출 저감을 체계적으로 실시 할 경우 국가적 차원에서 이산화탄소 배출량을 상당히 줄일 수 있을 것으로 판단되어 10개 기업체 대상으로 본 연구를 실시하였다. 온실가스 배출량은 최종에너지를 기준으로 산정한 경우 2004년 58,533천 톤 $CO_2$이며, 동일 년도 전국 온실가스 배출량인 592,600천톤 $CO_2$의 약 10%를 차지한다. 향후 2013년부터 한국이 2차 의무감축대상국이 될 경우 1990년도 온실 가스 배출 대비 5.2%의 감축률을 부여 받는다는 가정으로 경제적 손실액을 추정한 결과, 울산시의 경제적 손실은 1조에 가까운 것으로 나타났다. 따라서 울산지역은 최종 에너지소비가 2004년도에 전국 대비 12.5%로 매년 상승하고, 특히 2004년 1인당 최종에너지 소비의 경우 전국 평균은 3.38TOE이며, 울산시는 19.05TOE로 약 6배로 상당히 높게 나타났다. 또한 에너지 소비는 전국적인 규모로 비교하여 볼 때 점진적으로 증가하는 추세를 보이고 있다. 2003년의 경우 전국에너지 소비의 12.3%를 점유 하였던 것이 2010년에는 239.18백만 TOE로써 전국에너지 사용량의 14%를 점유 할 것이며, 점차 증가할 것으로 예상된다. 따라서 산업부문에서 에너지 사용비율이 80%이상으로 전국대비 에너지사용량이 상대적으로 높은 울산지역에서는 산업부문에서 온실가스발생량이 상당히 높은 것으로 예상 된다. 10개 기업체 중 5개 기업체의 온실가스 배출량 산정 및 인벤토리 구축 결과 온실가스 배출량의 공정에 따른 직접배출이 높은 것을 알 수 있었다. 또한 에너지 및 온실가스 저감을 위해 올 해 약 온실가스저감 227,554만원 경제적 효과가 나타났다. 또한 온실가스 이산화탄소 50,740 Ton/yr 절감효과를 발생하였다.

• The Magazine for Energy Service Companies
• /
• s.27
• /
• pp.16-19
• /
• 2004

합성고무를 주로 생산하는 금호석유화학 울산공장은 대표적인 에너지과다소비사업장이지만 각종 공정개선을 통한 에너지절감이 상당히 이루어지고 있다. 특히 정부자금을 활용하여 자금부담이 덜하고 신뢰할 수 있는 ESCO사업을 적극 활용, 쿨링워터시스템 개선사업을 비롯해 폐가스 보일러, 폐열회수시스템, 고효율조명 등 다양한 아이템으로 사업을 추진했다. 또한 이 공장은 그룹 차원에서 진행되는 에너지절감활동이 다채롭다.