• Membrane Journal
• /
• v.31 no.4
• /
• pp.275-281
• /
• 2021

To evaluate the possibility as a separator in alkaline water electrolysis, the thermal stability, ion conductivity and durability of 5 commercially available anion exchange membranes were tested. The thermal stability of FAAM-PK-75 and FAAM-40 membrane analyzed by thermo-gravimetric analysis (TGA) showed good performance compared to the other three types of AEM, AHO, and AHA membrane. The ion conductivity of AEM membrane measured in 7 M KOH solution at 25℃ and 80℃ had a higher value of about 4~17 times compared to the other membranes. The durability of FAAM-PK-75 tested in 7 M KOH solution at 25℃ was high compared to the other membranes.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.4
• /
• pp.417-423
• /
• 2022

With the emerging importance of catalysts for water electrolysis, developing efficient and inexpensive electrocatalysts for water electrolysis plays a vital role in renewable hydrogen energy technology. In this study, a 1nm thickness of TiC-supported Ru catalyst for hydrogen evolution reaction (HER) has been successfully fabricated using an electron (E)-beam evaporator and thermal decomposition of gaseous CH₄ in a furnace. The prepared Ru/TiC catalyst exhibited an outstanding performance for alkaline hydrogen evolution reaction with an overpotential of 55 mV at 10 mA cm^-2. Furthermore, we demonstrated that the outstanding HER performance of Ru/TiC was attributed to the high surface area of the support and the metal-support interaction.

• Journal of Electrochemical Science and Technology
• /
• v.8 no.3
• /
• pp.183-196
• /
• 2017

The research efforts directed at advancing water electrolysis technology continue to intensify together with the increasing interest in hydrogen as an alternative source of energy to fossil fuels. Among the various water electrolysis systems reported to date, systems employing a solid polymer electrolyte membrane are known to display both improved safety and efficiency as a result of enhanced separation of products: hydrogen and oxygen. Conducting water electrolysis in an alkaline medium lowers the system cost by allowing non-platinum group metals to be used as catalysts for the complex multi-electron transfer reactions involved in water electrolysis, namely the hydrogen and oxygen evolution reactions (HER and OER, respectively). We briefly review the anion exchange membranes (AEMs) and electrocatalysts developed and applied thus far in alkaline AEM water electrolysis (AEMWE) devices. Testing the developed components in AEMWE cells is a key step in maximizing the device performance since cell performance depends strongly on the structure of the electrodes containing the HER and OER catalysts and the polymer membrane under specific cell operating conditions. In this review, we discuss the properties of reported AEMs that have been used to fabricate membrane-electrode assemblies for AEMWE cells, including membranes based on polysulfone, poly(2,6-dimethyl-p-phylene) oxide, polybenzimidazole, and inorganic composite materials. The activities and stabilities of tertiary metal oxides, metal carbon composites, and ultra-low Pt-loading electrodes toward OER and HER in AEMWE cells are also described.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.1
• /
• pp.81-87
• /
• 2006

In marine air pollution control, SCR (Selective Catalytic Reduction) is reconized as the most effect method to control NOx, but on the other hand. seawater scrubber applying the basic characteristic that is naturally alkaline (pH typically around 8.1) is viewed as an economical SOx removal system at present. Especially, seawater scrubber would not be necessary to follow any of the various land based flue gas desulfurization methods. i.e. wet, dry or alkali scrubbing. However, these methods are not readily adaptable to marine conditions due to the quantifies of consumables required i.e. lime or limestone, the means of operation and the commercial availability. This research is undertaken to develop a new method as the main target of eliminating all exhaust emissions, particularly vessel, because of easy access to seawater and apt to apply a wet scrubber system. First, using the acidic seawater by seawater electrolysis, nitric monoxide(NO) is adequately oxidized to nitric dioxide $(NO_2)$by ClOx-in the acidic seawater, the electrolyzed alkaline seawater by electrolysis which contains mainly NaOH together with alkali metal ions $(i.e\;Na^{+}\;K^{+},\;Mg_{2}\;^{+},\;Ca_{2}\;^{+})$, is used as the absorption medium of NOx, the SOx are absorbed by relatively high solubility compared to other components of exhaust pollutants. The results found that the NOx and SOx removals could be achieved nearly Perfect.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.41 no.6
• /
• pp.37-42
• /
• 2004

It is necessary for what just keep a living body balance be devoted to it being varied with acidity serious trouble, and constitution of a study person about the density (ph) change that an alkaline ion necessary for a living body is numerical to supply a human body with number alkali by PWM voltage control. Works in the water which included the calcium (Ca), kalium (K), magnesium (Mg), natrium (Na) back who is helpful for a human body, and there is Alkaline. It is done this alkaline electrolysis to ask in order to create a number, and minerals are gathered through isolated layer (isolated special layer) to a - electrode direction, and is created. of course, prominent derelicts gather, and the acidity capital is happened, and -ion of a chlorine (Cl), phosphorus(P), sulfur (S) back is usable unfavorably in water of different use to a + electrode direction. Microprocessor was used with a - pole and a + pole with a PWM(pulse width modulation) voltage in this electrolysis process, and four kinds of PWM voltages were implemented, and a voltage every ph density change tried to be considered. It is expected by getting exactly if number alkaline ion of ph density value necessary is done with setting value if PWM control is used thus.

• Journal of the Korean Institute of Gas
• /
• v.28 no.2
• /
• pp.17-23
• /
• 2024

As interest in sustainable and eco-friendly energy increases due to various problems in the carbon economy, a hydrogen economy that utilizes hydrogen as a main energy source is emerging. Among the methods of producing hydrogen, the water electrolysis method based on renewable energy produces environmentally friendly green hydrogen because it produces hydrogen from water. The water electrolysis facility currently under development produces hydrogen by receiving electricity directly from renewable energy and uses KOH(potassium hydroxide) as an electrolyte. In this study, HAZOP(Hazard and Operability Study), a qualitative risk assessment, was conducted on alkaline water electrolysis facilities to find problems and risk factors in the design and operation of water electrolysis facilities. Risks related to oxygen and KOH, an electrolyte, were identified as major risks, and it is believed that the safety of facilities and workers can be secured based on emergency action plans and safe operation procedures.

• Membrane Journal
• /
• v.23 no.6
• /
• pp.469-474
• /
• 2013

An anion exchange membrane was prepared for a separator in the alkaline water electrolysis. An anion exchange membrane was prepared by the chloromethylation and amination of polyvinyl chloride (PVC) used as a base polymer. The membrane properties of the prepared anion exchange membrane such as the membrane resistance and ion exchange capacity were measured. The minimum membrane resistance of the prepared anion exchange membrane was $2.9{\Omega}{\cdot}cm^2$ in 1M NaOH aq. solution. This membrane had 2.17 meq./g-dry-membrane and 43.4% for the ion exchange capacity and water content, respectively. The membrane properties of the prepared anion exchange membrane was compared with that of the commercial anion exchange membrane. The membrane resistance decreased in the order; AHT>IOMAC> Homemade membrane> AHA>APS=AFN. The ion exchange capacity decreased in the order; Homemade membrane>AFN>APS>AHT>AHA>IOMAC.

• Transactions of the Korean hydrogen and new energy society
• /
• v.31 no.1
• /
• pp.23-32
• /
• 2020

The intermittent characteristics of renewable energy complicates the process of balancing supply with demand. Electrolysis technology can provide flexibility to grid management by converting electricity to hydrogen. Alkaline electrolysis has been recognized as established technology and utilized in industry for over 100 years. However, high overpotential of oxygen evolution reaction in alkaline water electrolysis reduces the overall efficiency and therefore requires the development of anode catalyst. In this study, Raney Ni-Zn-Fe electrode was prepared by electroplating and the electrode characteristics was studied by varying electroplating parameters like electrodeposition time, current density and substrate. The prepared Raney Ni-Zn-Fe electrode was electrochemically evaluated using linear sweep voltammetry. Physical and chemical analysis were conducted by scanning electron microscope, energy dispersive spectrometer, and X-ray diffraction. The plating time did not changed the morphology and composition of the electrode surface and showed a little effect on overpotential reduction. As the plating current density increased, Fe content on the surface increased and cauliflower-like structure appeared on the electrode surface. In particular, the overpotential of the electrode, which was prepared at the plating current density of 320 mA/㎠, has showed the lowest value of 268 mV at 50 mA/㎠. There was no distinguishable overpotential difference between the type of substrate for the electrodes prepared at 80 mA/㎠.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.7
• /
• pp.269-274
• /
• 2013

We are used with the alkaline ion water which an application field does to object for drinking water compare with the alkaline ion water which asked ion acid electrolysis so as to be very different. This is used with sterilization disinfection use by residual chlorine in case of strong acidity according to ph intensity, and in case of middle acidity use by washing and face washing, and mix with meal materials in case of weak acidity widely usable in cooking. Acid ion water generates as we electrolyze water. Chlorine gas and sodium hydroxide etc. was generated at electrolysis process, and we have toward sterilizing power. Derelicts such as chlorine, phosphorus, sulfur etc. are gathered from a negative ion, and we make acid ion water to + electrode direction in electrolysis. We used a diaphragm in order to disconnect too acid water and alkaline water. We implemented so that the acid water which it came down to three kinds of PWM voltage to PWM (pulse width modulation) control, and implementation method of ph intensity change authorized ph intensity between weak acidity to electrode in strong acidity as we used Microprocessor, and intensity was adjusted successively by PWM control was generated.

• Journal of the Korean institute of surface engineering
• /
• v.55 no.2
• /
• pp.38-50
• /
• 2022

As a low-cost and high-efficiency electrocatalysts with high performance and stability become a key challenge in the development of the practical use of water electrolysis, there is an intense interest in transition-metal oxalate-based materials. Transition-metal oxalate-based catalysts with excellent electrochemical performances have been widely applied in water electrolysis due to its low-cost and ease of synthesis. This review provides a useful summary on the development of transition-metal oxalate as potential catalysts for water electrolysis with a focus on the structural and compositional alteration, role of oxalate anion, and enhanced electrochemical performances.