• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.25-33
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• 2003

It summarized about the application of the membrane technology in thermochemical water-splitting iodine-sulfur process that was hydrogen production using the nuclear heat from the High Temperature Gas-Cooled Reactor (HTGR). Thermochemical water-splitting hydrogen production method using the high temperater nuclear thermal energy could be realized and remained to be solved the investigation subject. And, it is possible for mass-production of hydrogen such as one of the clean energy in future.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.13-16
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• 2006

Electro-electrodialysis (EED) experiments were carried out for the HI concentration from HIx $(HI-H_2O-I_2)$ solution to improve the Hl decomposition reaction in the thermochemical water-splitting is (iodine-Sulfur) process. EED cell is composed of the collector electrode and electrolyte. Nafion 117 which was cation exchange membrane used as an electrolyte, and the activated carbon cloth used as an electrode. The HI concentration experiment was carried out using the HIx solution and molar ratio of the $I_2$ were varied from 1 to 3 mole. The cell voltages were decreased as temperature increase. And, membrane properties such as transport number of proton and electro-osmosis coefficient were decreased as temperature increase

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.109-115
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• 2007

Solar energy conversion to hydrogen was carried out via a two-step thermochemical water splitting using metal oxide redox pair. To simulate the solar radiation, a 7 kW short arc Xe-lamp was used. Partially reduced iron oxide and cerium oxide have the water splitting ability, respectively. So, $Fe_3O_4$ supported on $CeO_2$ was selected as the active material. $Fe_3O_4/CeO_2$(20 wt/80 wt%) was prepared by impregnation method, then the active material was washcoated on the ceramic honeycomb monolith made of mullite and cordierite. Oxygen was released at the reduction step($1673{\sim}1823\;K$) and hydrogen was produced from water at lower temperature($873{\sim}1273\;K$). The result demonstrate the possibility of the 2-step thermochemical water splitting hydrogen production by the active material washcoated monolith. And hydrogen and oxygen was produced separately without any separation process in a monolith installed reactor. But the SEM and EDX analysis results revealed that the support used in this experiment is not suitable due to the thermal instability and coating material migration.

• New & Renewable Energy
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• v.20 no.1
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• pp.110-115
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• 2024

Global sustainable energy needs and carbon neutrality goals make hydrogen a key future energy source. South Korea and Japan lead with proactive hydrogen policies, including South Korea's Hydrogen Law and Japan's strategy updates aiming for a hydrogen-centric society by 2050. A notable advance is the solar thermal chemical water-splitting cycle for green hydrogen production, spotlighted by Korea Institute of Energy Research (KIER) and Niigata University's joint initiative. This method uses solar energy to split water into hydrogen and oxygen, offering a carbon-neutral hydrogen production route. The study focuses on international collaboration in solar energy for thermochemical water-splitting and E-fuel production, highlighting breakthroughs in catalyst and reactor design to enhance solar thermal technology's commercial viability for sustainable fuel production. Collaborations, like ARENA in Australia, target global carbon emission reduction and energy system sustainability, contributing to a cleaner, sustainable energy future.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.3
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• pp.204-213
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• 2002

In this work, hydrogen production by a 2-step water-spritting thermochemical cycle based on metal oxides redox pairs was investigated on the bases of the thermodynamics and technical feasibility. Also, a 2nd-law analysis performed on the closed cyclic process indicates a maximum exergy conversion efficiency of 7.1% when using a solar cavity-receiver operated at 2300K and air/Fe3O4 molar ratio = 10.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.356-364
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• 2007

The partial reduction and water splitting properties of metal substituted ferrite mediums for two-step thermochemical hydrogen production, were carried out by TPR/O(Temperature programmed reduction/oxidation) method at a temperature of below 1173 K and under atmospheric pressure. $ZrO_2$ was added to the ferrite as a binder to prevent the sintering. As the results, the reactivity of the metal species added to the ferrite mediums decreased in the order of Cu>Co>Ni>Mn, on the basis of water-splitting temperature. It was also found that the produced hydrogen amounts in the water-splitting step on partial reduced mediums were corresponding to the consumed hydrogen amounts in the previously partial reduction step.

• Membrane Journal
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• v.14 no.3
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• pp.185-191
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• 2004

It summarized about the properties of thermochemical water-splitting iodine-sulfur process that was hydrogen production using the waste heat from the High Temperature Gas-Cooled Reactor (HTGR) recycling the heat of nuclear power. It was mainly explained about the application of membrane separation technique in IS process. Thermochemical water-splitting hydrogen production method using the high temperature nuclear thermal energy could be realized and remained to be solved the investigation subject. And, it is possible for mass-production of hydrogen such as one of the clean energy in future.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.113-119
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• 2012

The two-step water splitting thermochemical cycle is composed of the T-R (Thermal Reduction) and W-D (Water Decomposition) steps. The mechanism of this cycle is oxidation-reduction, which produces hydrogen. The reaction temperature necessary for this thermochemical cycle can be achieved by a dish-type solar thermal collector (Inha University, Korea). The purpose of this study is to validate a water splitting device in the field. The device is studied and fabricated by Kodama et al (2010, 2011). The validation results show that the foam device, when loaded with $CeO_2$ powder, was successfully achieved hydrogen production under field conditions. Through this experiment, we can analyze the characteristics of the catalyst and able to determine which is more advantageous thing to produce hydrogen compared with previous experiment that used ferrite-device.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.11-18
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• 2014

Two-step water splitting thermochemical cycle with $CeO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2$ foam device depending on reaction temperature of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. As a result, the amount of reduced $CeO_2$ considerably varies according to the reaction temperature of Thermal-Reduction step. and hydrogen production was not much when the amount of reduced $CeO_2$ decreased even if the reaction temperature of Water-Decomposition step was high. Therefore, it is very important to keep the reaction temperature of Thermal-Reduction step high in two-step thermochemical cycle with $CeO_2$.

• Transactions of the Korean hydrogen and new energy society
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• v.1 no.1
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• pp.40-47
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• 1989

The sulfur-iodine thermochemical water splitting process of GA(General atomic) cycle was studied to produce hydrogen from water by $H_2-I_2-SO_2$ reactions. The experimental scale was 500g based on iodine. The reaction took 100 minutes, products could be separated two liquid phases due to their density difference:HI solution had a density of 2.39~2.61g/cc, and $H_2SO_4$ solution had 1.37~1.38g/cc. The condition of reaction was when weight ratio of $I_2/H_2O$ was 2/1 resulting in good phase separation and productivity.