• 한국수소및신에너지학회논문집
• /
• 제19권1호
• /
• pp.64-70
• /
• 2008

This paper briefly discusses the main sources of errors and their solutions for measuring hydrogen uptake from gas phase by the Sieverts technique. Correction of volumetric errors of apparatus, density of hydrogen storage material, estimation of temperature gradient are investigated. Systematic errors and the change of density of the host material according to the pressure have been the subject of much controversy in recent years. We considered the standard ball calibration, temperature gradient distribution, pretreatment of hydrogen storage materials to minimize errors. We could lessen the miscalculations after applying those methods to Equilibrium pressure-composition isotherm data.

• 한국세라믹학회지
• /
• 제38권10호
• /
• pp.867-870
• /
• 2001

지지촉매로 Ni-graphite를 사용하고 ${C_2}{H_2}$를 이용한 열화학기상증착법에 의하여 탄소나노소재를 합성하였다. 합성된 시편은 SEM, TEM, 라만 분광법으로 분석하였으며, 수소저장특성은 전기화학적인 방법에 의하여 평가하였다. 탄소나노소재 합성시 메카노케미컬 처리과정을 거친 시편이 거치지 않은 시편에 비하여 탄소나노튜브의 순도가 우수하였다. 한편, 탄소나노소재를 정제함에 따라 수소저장특성이 크게 향상되었다.

• 에너지공학
• /
• 제18권2호
• /
• pp.141-146
• /
• 2009

본 연구에서는 열화학증착법을 이용하여Pt 및 Pd 전이금속 촉매를 각각 5nm, 3nm로 탄소나노튜브에 증착하여 수소저장특성을 연구하였다. 제작한 시료를 수소분위기에서 $200^{\circ}C$의 조건에서 1시간동안 열처리한 후 $25^{\circ}C$, 33~34atm의 조건에서 수소저장량을 측정하였다. 이 조건에서 수소저장량은 3.2wt%로 나타났고 동일 조건에서 반복 수행결과 수소저장과 탈착을 반복하여도 3.1wt%의 저장량을 보여 수소저장량의 변화가 거의 없음을 관찰하였다. 그러나 4번째 저장cycle이후에는 수소저장량이 1.5wt%로 급격히 감소하였다. 이는 증착된 전이금속촉매의 조대화로 인해 저장량이 감소함을 확인하였다. 실험결과를 근거로 Pt 및 Pd 2금속을 증착한 탄소나노튜브의 수소저장메커니즘을 제시하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.230-230
• /
• 2009

In this work, Porous Carbons (PCs) were prepared by using a chemical acid treatment, and the hydrogen storage behaviors of PCs doped by Pt nanoparticles were investigated. The hydrogen storage capacities of the Pt-doped carbons with a platinum content of 0.2 - 1.5 wt.% were evaluated by a volumetric adsorption method at 298K and 10 MPa. The microstructures of samples were examined by XRD and SEM. It was found that the hydrogen storage capacitiesof the PCs dramatically increased, but the amount of hydrogen stored from the samples began to decrease after 0.6 wt.% of Pt content due to the pore blocking. These results indicate that a suitable amount of supported catalysts and layer intervals of carbons had a very important impact on hydrogen storage behaviors.

• 한국수소및신에너지학회논문집
• /
• 제19권1호
• /
• pp.77-89
• /
• 2008

There are several materials for the hydrogen storage such as hydrogen storage alloy, carbon nanomaterials, non-carbon nanomaterials, compounds etc. Efficient and inexpensive hydrogen storage is an essential prerequisite for the utilization of hydrogen, one of the new and clean energy sources. Many researches have been widely performed for the hydrogen storage techniques and materials having high storage capacity and stability. In this paper, the patents concerning the carbon nanomaterial hydrogen storage method were gathered and analyzed. The search range was limited in the open patents of Korea(KR), Japan(JP), USA(US) and European Union(EP) from 1996 to 2006. Patents were gathered by using key-words searching and filtered by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.

• 한국수소및신에너지학회논문집
• /
• 제22권5호
• /
• pp.616-624
• /
• 2011

Hydrogen storage and release of Fe/Zr/Mo mixed oxide mediums were investigated by hydrogen reduction and water splitting oxidation($Fe_3O_4+4H_2{\rightleftharpoons}3Fe+4H_2O$). As the results of TPR/O, Mo was an additive to enhance the reactivity of water splitting oxidation as well as the stability of the medium. On the other hand, it seemed that $ZrO_2$ additive provided the passway for the diffusion of gaseous chemicals on the medium in repeated redox cycles. Among the Fe/Zr/Mo mediums, a FeZrMo-7 medium (Fe/Zr/Mo=80/13/7mol%) exhibited the best performance with good durability during five repeated redox cycles. The amount of hydrogen evolved on the medium was maintained at ca. 10.7mmol-$H_2$/g-medium corresponding to the hydrogen storage amount of ca. 2.2wt%.

• Korean Chemical Engineering Research
• /
• 제49권5호
• /
• pp.644-651
• /
• 2011

향후 도래할 수소경제에서 가장 유망한 기술 중에 하나인 고체수소저장 시스템들의 전체성능은 고체수소화물 내부의 열 및 물질전달 속도에 크게 영향을 받으며, 최적화된 시스템 설계를 위해서 이들에 대한 연구들이 선행되어야 한다. 본 연구에서는 Pt-CNTs 수소저장물질을 이용한 수소저장시스템에 대한 모델링 및 2차원 비정상상태 전산해석을 수행하였다. 기존 상용화된 CFD 소프트웨어를 이용하여 충전동안 발생하는 열 및 물질전달에 대한 현상들을 연구하였으며, 최적화된 수소저장시스템 설계는 고압에서 대류에 의한 냉각효과를 최대화하여 시스템 내부의 온도 상승과 충전시간 지연을 개선할 수 있음을 밝혀냈다. 아직까지 CNT 기반의 수소저장시스템에 대한 연구들이 보고되고 있지 않은 상황에서, 본 연구는 향후 CNT 기반의 고체수소저장시스템 최적 설계에 대한 방안들을 제시한다.

• 한국군사과학기술학회지
• /
• 제15권4호
• /
• pp.519-526
• /
• 2012

Recently fuel cell is considered to be a new technology that can substitute the ICE(Internal Combustion Engine) as well as overcome environmental issues. In military applications, fuel cell has an unique advantages, which are quietness, namely, stealth. The environmental requirement such as shock and vibration in military application, however, is very severe comparing to civilian demand. Especially, the safety concerning hydrogen storage is the most important problem. Among the candidate methods to store hydrogen, the metal hydride storage is promising method owing to the storage mechanism of chemical absorption of hydrogen to metal hydrides. In this study, the new composition of Ti-Zr type metal hydride(A composition) was suggested and investigated to increase the hydrogen storage capacity. For comparison, the hydrogen charge-discharge properties were investigated with the commercialized Ti-Zr type metal hydride(B composition) using PCT(Pressure-Composition-Temperature) measurement. Also two hydrogen storage cylinders were loaded with each metal hydride and their hydrogen charging and discharging characteristics were investigated. As a result, it was found that the new Ti-Zr type metal hydride has a slightly higher hydrogen storage capacity compared to commercial Ti-Zr type metal hydride.

• Bulletin of the Korean Chemical Society
• /
• 제35권1호
• /
• pp.253-256
• /
• 2014

Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

• 한국수소및신에너지학회논문집
• /
• 제31권6호
• /
• pp.564-570
• /
• 2020

Metal hydride is suitable for safe storage of hydrogen. The hydrogen storage kinetics of the metal hydride are highly dependent on its heat transfer characteristics. This study presents a metal hydride-expended graphite composite with improved thermal conductivity and its hydrogen storage kinetics. To improve the heat transfer characteristics, a metal hydride was mixed and compacted with a high thermal conductivity additive. As the hydrogen storage material, AB5 type metal hydride La0.9Ce0.1Ni5 was used. As an additive, flakes-type expended graphite was used. With improved heat transfer characteristics, the metal hydride-expended graphite composite stores hydrogen four times faster than metal hydride powder.