• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.51-56
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• 1997

Laves상 $ZrV_2$합금은 다량의 수소를 저장하지만 수소와의 결합력이 강하여 Ni-MH전지의 전극으로는 부적당하다. 전극에 응용하기 위해 $ZrV_2$합금중의 V의 일부를 Ni로 치환하여 수소와의 결합력을 약하게 하였다. 이와 같은 Zr-V-Ni계 합금에 대해 전기화학적 성질, 전극의 평형전위로부터 합금중의 수소의 열역학적성질 및 2차전지전극에의 응용가능성을 조사하였다.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1596-1600
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• 2010

Surface functionalization of multi-walled carbon nanotubes (MWNTs) was carried out by means of acid treatment. The presence of oxygen functional groups on the surface of acid-treated MWNTs was confirmed with the aid of Fourier transform infrared spectroscopy and X-ray spectroscopy. In addition, carboxylic groups generally formed on the surface of acid-treated MWNTs, and the dispersion was increased by the duration of the acid treatment. The zeta-potential indicated the surface charge transfer and the dispersion of MWMTs. Morphological characteristics of acid-treated MWNTs were also observed using a transmission electron microscopy, X-ray diffraction, and Raman analysis, which was revealed the significantly unchanged morphologies of MWNTs by acid treatment. The hydrogen adsorption capacity of the MWNTs was evaluated by means of adsorption isotherms at 77 K/1 atm. The hydrogen storage capacity was dependent upon the acid treatment conditions and the formation of oxygen functional groups on the MWNT surfaces. The latter have an important effect on the hydrogen storage capacity.

• 한국수소및신에너지학회논문집
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• 제22권3호
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• pp.380-385
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• 2011

$MgH_2$ was synthesized by hydriding chemical vapor deposition (HCVD). In this study, we examined the hydrogen storage property of $MgH_2$ synthesized by HCVD. The results of pressure-composition-temperature (PCT) measurement showed that the HCVDed $MgH_2$ reversibly absorbed hydrogen as much as 6 wt%. Each hydrogenation rate was very greater than the conventional alloy methods. The reason was that the particle size made by HCVD was small as approximately 1 ${\mu}m$. The PCT of $MgH_2$ made by HCVD methode was similar to a commercial $MgH_2$. The ${\Delta}H$ and ${\Delta}S$ value are respectively -76.8 $kJ/mol{\cdot}H_2$ and -137.4 $kJ/mol{\cdot}H_2$. Mg made by HCVD methode was activated easily than commercial Mg. Also the initial reaction rate was faster than that of commercial $MgH_2$. 70% of the total storage were stored during 400s.

• 한국수소및신에너지학회논문집
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• 제26권4호
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• pp.301-307
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• 2015

We present a study of hydrogen liquefaction using the CFD (Computational Fluid Dynamics) program. Liquid hydrogen has been evaluated as the best storage method because of high energy per unit mass than gas hydrogen, but efficient hydrogen liquefaction and storage are needed in order to apply actual industrial. In this study, we use the CFD program that apply navier-stokes equation. A hydrogen is cooled by heat transfer with the while passing gas hydrogen through Cu tube. We change diameter and flow rate and observe a change of the temperature and flow rate of gas hydrogen passing through Cu tube. As a result of, less flow rate and larger diameter are confirmed that liquefaction is more well. Ultimately, When we simulate the hydrogen liquefaction by using CFD program, and find optimum results, it is expected to contribute to the more effective and economical aspects such as time and cost.

• Korean Chemical Engineering Research
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• 제53권5호
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• pp.584-589
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• 2015

잠수함 및 수중무인체계 등의 산소희박환경에서 연료전지를 통한 효과적인 전력생산을 위해서는 높은 수소저장밀도를 갖는 수소공급원이 필요하다. 디젤연료는 액체연료로서 저장 및 공급이 용이하며, 연료전지의 연료가 되는 수소의 단위질량 및 단위부피당 저장밀도가 높은 장점을 갖고 있다. 이러한 디젤연료의 장점을 기반으로 본 연구에서는 산소희박환경에서 수소생산을 위해 디젤연료의 개질반응을 이용하였으며, 산화제로 단위부피당 산소 저장밀도가 높고 액상으로 보관이 용이한 과산화수소 수용액을 기존의 산화제인 물과 산소의 대체산화제로 이용하는 방법을 제안하였다. 과산화수소 수용액의 디젤개질 산화제로써의 특성을 파악하기 위해 물, 공기 산화제와의 비교실험을 진행하였으며, 기존의 산화제와 디젤 개질반응 시 동일한 특성을 갖는 것을 실험적으로 확인하였다. 또한 상용디젤을 연료로 온도 및 과산화수소 수용액의 농도에 따른 개질성능을 평가하였으며, 49시간의 가속 열화실험을 통하여 디젤, 과산화수소 수용액을 이용한 수소생산의 가능성을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제31권2호
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• pp.184-193
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• 2020

One of the technical methods to increase the volumetric energy density of hydrogen is to pressurize the gaseous hydrogen and then contain it in a rigid vessel. Especially for automotive systems, the compressed hydrogen storage can be found in cars as well as at refueling stations. During the charging the pressurized hydrogen into a vessel, the temperature increases with the amount of stored hydrogen in the vessel. The temperature of the vessel should be controlled to be less than a limitation for ensure stability of material. Therefore, the accurate estimation of temperature is of significance for safely storing the hydrogen. In this work, three well-known cubic equations of state (EOSs) were adopted to examine the accuracy in regenerating thermodynamic properties of hydrogen within the temperature and pressure ranges for the compressed hydrogen storage. The formulations representing molar volume, internal energy, enthalpy, and entropy were derived for Redlich-Kwong (RK), Soave-Redlioch-Kwong (SRK), and Peng-Robinson (PR) EOSs. The calculated results using the EOSs were compared with literature data given by NIST. It was revealed that the accuracies of RK and SRK EOSs were satisfactorily compatible and better than the results by PR EOS.

• 한국표면공학회지
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• 제56권6호
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• pp.371-379
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• 2023

Ammonia, which is closely related to our lives, has a significant impact on our lives as a representative substance for crop cultivation. Recently, it has gained attention as an efficient and productive hydrogen/storing substance that can replace fossil fuels. Efforts are being made to utilize it as a renewable energy source through thermochemical and electrochemical reactions. However, the use of ammonia, which encompasses the era, carries inherent toxicity, so a comprehensive understanding of ammonia safety is necessary. To ensure safety in the transportation and storage of ammonia and chemical substances domestically and internationally, national and organizational standards are being developed and provided through documents and simple symbols to help people understand. This review explores the chemical characteristics of ammonia, its impact on human health, and the global trends in safety standards related to ammonia. Through this examination, the paper aims to contribute to the discourse on the safety and risk management of ammonia transport and storage, crucial for achieving carbon neutrality and expanding the hydrogen economy.

• Carbon letters
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• 제16권2호
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• pp.127-131
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• 2015

In this work, highly porous carbons were prepared by chemical activation of carbonized biomass-derived aerogels. These aerogels were synthesized from watermelon flesh using a hydrothermal reaction. After carbonization, chemical activation was conducted using potassium hydroxide to enhance the specific surface area and microporosity. The micro-structural properties and morphologies were measured by X-ray diffraction and scanning electron microscopy, respectively. The specific surface area and microporosity were investigated by $N_2$/77 K adsorption-desorption isotherms using the Brunauer-Emmett-Teller method and Barrett-Joyner-Halenda equation, respectively. Hydrogen storage capacity was dependent on the activation temperature. The highest capacity of 2.7 wt% at 77 K and 1 bar was obtained with an activation temperature of $900^{\circ}C$.

• 한국수소및신에너지학회논문집
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• 제1권1호
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• pp.31-39
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• 1989

Although it has been well known that many metal hydrides are promising to use for hydrogen storage and other applications, some difficulties still remain. Metal hydrides, particularly in powder form, have very poor thermal conductivity. The hydrogen storage alloys degrade intrinsically or extrinsically during repeated hydriding and dehydriding. Elimination of these problems is very important in the practical applications. In order to prevent degradation and to improve the thermal conductivity, the hydrogen storage characteristics of rare-earth type alloy encapsulated with Cu or Ni by means of chemical plating have been investigated. No changes has occured in hydrogen absorption capacity and equilibrium pressure even though the alloy powder is microencapsulated. The first hydrogen absorption rate of the alloy encapsulated increased considerably comparing to uncapsulated sample. In the case of encapsulating the fine powder ($>10{\mu}m$) and subsequent compacting by $8ton/cm^2$, shape of compact is maintained regardless of hydriding and dehydriding. The degree of degradation of the alloy caused by impurity gas of CO or $O_2$ was decreased prominently by encapsulation.

• 한국수소및신에너지학회논문집
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• 제15권2호
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• pp.108-118
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• 2004

To find out rational design and synthetic strategies toward efficient hydrogen storage materials, molecular modeling and quantum mechanical studies have been carried out on the MOFs(Metal-Organic Frameworks) having various organic linkers and nanocube frameworks. The calculation results about the free volume ratio, surface area, and electron density variation of the frameworks indicated that the capacity of the hydrogen storage of MOFs was largely dependent on the specific surface area and electron localization around benzene ring rather than the free volume of MOFs. The prediction of the modeling study could be supported by the hydrogen adsorption experiments using IRMOF-1 and -3, which showed more enhanced hydrogen storage capacities of IRMOF-3 compared with the IRMOF-1's at both experimental conditions, 77K, ∠ $H_2$ 1 atm and ambient temperature, ∠ $H_2$ 35 atm.