• Title/Summary/Keyword: Water Electrolysis

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Various Problems in Oxygen-evolution Reaction Catalysts in Alkaline Conditions and Perovskites Utilization (저온형 알칼라인 산소발생반응의 문제점과 perovskites촉매 개발 동향)

  • Lee, Jin Goo
    • Ceramist
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    • v.22 no.2
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    • pp.182-188
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    • 2019
  • Alternative energy sources to the systems using hydrocarbon fuels have been actively developed due to exhaustion of fossil fuels and issue of global warming by CO2. Fuel cells have attracted great attentions to solve these issues as electricity can be produced with product of clean H2O by using H2-O2 as a fuel. Besides, using reverse reactions make it possible to produce H2 and O2 gas from electrolysis of water. There are various fuel cells systems depending on the types of electrolyte, and in this mini-reviews, the main aim is to focus on perovskite oxides as a catalyst for oxygen-evolution reactions in alkaline electrolysis and its potential to application of alkaline electrolysis systems.

Cation exchange membrane and anion exchange membrane aided electrolysis processes for hypochlorite generation

  • Seong K. Kim;Dong-Min Shin;Ji Won Rhim
    • Membrane and Water Treatment
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    • v.14 no.2
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    • pp.55-63
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    • 2023
  • In this study, the influence of different IEMs (ion exchange membranes) to performance of the hypochlorite electrolysis unit with Cl2 recovery stream was investigated. More specifically, Nafion 117-a representative cation exchange membrane (CEM)-and aminated polypheylene oxide (APPO)-an anion exchange membrane (AEM)-were installed in the hypochlorite electrolysis unit, and the performance and the energy efficiency of the units were evaluated and compared. Regardless of whether CEM (Nafion 117) or AEM (APPO) was installed, the rate of hypochlorite generation was increased (by up to 24.3% and 22.2% for Nafion 117 and APPO, respectively) compared with the unit without an IEM. On the other hand, the power efficiency and the optimum operation condition of hypochlorite production units seem to depend on the conductivity and stability of the installed IEM. As the result, between Nafion 117 and APPO, higher performance and efficiency were achieved with Nafion 117, due to excellent conductivity and stability of the membrane.

Sulfonated poly(arylene ether copolymer)-g-sulfonated Polystyrene Membrane Prepared Via E-beam Irradiation and Their Saline Water Electrolysis Application (전자빔조사를 이용한 술폰화 폴리아릴렌 에테르 술폰-g-술폰화 폴리스틸렌 분리막 제조 및 염수전기분해 특성평가)

  • Cha, Woo Ju;Lee, Chang Hyun
    • Membrane Journal
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    • v.26 no.6
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    • pp.458-462
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    • 2016
  • Saline water electrolysis, known as chlor-alkali (CA) membrane process, is an electrochemical process to generate valued chemicals such as chlorine, hydrogen and sodium hydroxide with high purities higher than 99%, using an electrolytic cell composed of cation exchange membrane, anode and cathode. It is necessary to reduce energy consumption per a unit chemical production. This issue can be solved by decreasing intrinsic resistance of the membrane and the electrodes and/or by reducing their interfacial resistance. In this study, the electron radiation grafting of a $Na^+$ ion-selective polymer was conducted onto a hydrocarbon sulfonated ionomer membrane with high chemical resistance. This approach was effective in improving electrochemical efficiency via the synergistic effect of relatively fast $Na^+$ ion conduction and reduced interfacial resistance.

Characterization of Ni-Fe Alloy Electrodeposited Electrode for Alkaline Water Electrolysis (알칼라인 수전해용 Ni-Fe 합금 전착 전극의 특성)

  • AN, DA-SOL;BAE, KI-KWANG;PARK, CHU-SIK;KIM, CHANG-HEE;KANG, KOUNG-SOO;CHO, WON-CHUL;CHO, HYUN-SEOK;KIM, YOUNG-HO;JEONG, SEONG-UK
    • Journal of Hydrogen and New Energy
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    • v.27 no.6
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    • pp.636-641
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    • 2016
  • Alkaline water electrolysis is commercial hydrogen production technology. It is possible to operate MW scale plant. Because It used non-precious metal for electrode. But It has relatively low current density and low efficiency. In this study, research objective is development of anode for alkaline water electrolysis with low cost, high corrosion resistance and high efficiency. Stainless steel 316L (SUS 316L) was selected for a substrate of electrode. To improve corrosion resistance of substrate, Nickel (Ni) layer was electrodeposited on SUS 316L. Ni-Fe alloy was electrodeposited on the passivated Ni layer as active catalyst for oxygen evolution reaction(OER). We optimized preparation condition of Ni-Fe alloy electrodeposition by changing current density, electrodeposition time and composition ratio of Ni-Fe electrodeposition bath. This electrodes were electrochemically evaluated by using Linear sweep voltammetry (LSV) and Cyclic voltammetry (CV). The Ni-Fe alloy (Ni : Fe = 1 : 1) showed best activity of OER. The optimized electrode decreased overpotential about 40% at $100mA/cm^2$ compared with Ni anode.

Electrochemical Characteristics of Solid Polymer Electrode Fabricated with Low IrO2 Loading for Water Electrolysis

  • Ban, Hee-Jung;Kim, Min Young;Kim, Dahye;Lim, Jinsub;Kim, Tae Won;Jeong, Chaehwan;Kim, Yoong-Ahm;Kim, Ho-Sung
    • Journal of Electrochemical Science and Technology
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    • v.10 no.1
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    • pp.22-28
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    • 2019
  • To maximize the oxygen evolution reaction (OER) in the electrolysis of water, nano-grade $IrO_2$ powder with a low specific surface was prepared as a catalyst for a solid polymer electrolyte (SPE) system, and a membrane electrode assembly (MEA) was prepared with a catalyst loading as low as $2mg\;cm^{-2}$ or less. The $IrO_2$ catalyst was composed of heterogeneous particles with particle sizes ranging from 20 to 70 nm, having a specific surface area of $3.8m^2g^{-1}$. The anode catalyst layer of about $5{\mu}m$ thickness was coated on the membrane (Nafion 117) for the MEA by the decal method. Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) confirmed strong adhesion at the interface between the membrane and the catalyst electrode. Although the loading of the $IrO_2$ catalyst was as low as $1.1-1.7mg\;cm^{-2}$, the SPE cell delivered a voltage of 1.88-1.93 V at a current density of $1A\;cm^{-2}$ and operating temperature of $80^{\circ}C$. That is, it was observed that the over-potential of the cell for the oxygen evolution reaction (OER) decreased with increasing $IrO_2$ catalyst loading. The electrochemical stability of the MEA was investigated in the electrolysis of water at a current density of $1A\;cm^{-2}$ for a short time. A voltage of ~2.0 V was maintained without any remarkable deterioration of the MEA characteristics.

Evaluating the Durability of Concrete Combined with Ground Granulated Blast Furnace Slag using Electrolysis Alkaline Aqueous as Mixing Water (전기분해 알칼리수를 배합수로 사용한 고로슬래그 미분말 혼입 콘크리트의 내구성)

  • Jeong, Su-Mi;Kim, Ju-Sung;Park, Sun-Gyu
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.4
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    • pp.349-358
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    • 2023
  • This research aimed to enhance the initial strength of concrete that is mixed with ground granulated blast furnace slag, as well as to fortify its resistance to carbonation and chloride ion permeation. To achieve this, alkaline aqueous, produced through the electrolysis of potassium carbonate, was employed as the mixing water in the preparation of concrete. To substantiate the increment in initial strength, compressive strength measurements of the concrete were executed. Additionally, an accelerated carbonation test and a chloride ion permeation resistance test were undertaken. The results confirmed that the initial strength of the concrete, which utilized electrolysis alkaline aqueous as mixing water, exhibited an improvement in comparison to concrete mixed with conventional water. It was also verified that both carbonation resistance and chloride ion permeation resistance showed enhancements.

Influence of Operation Conditions on the Performance of PEM Water Electrolysis (운전조건이 PEM 수전해 셀의 성능에 미치는 영향)

  • Sangyup Jang;Jaedong Kim;Jinmo Park;Youngseuk So
    • Journal of the Korean Institute of Gas
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    • v.28 no.1
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    • pp.65-72
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    • 2024
  • Green Hydrogen demonstration complex is under conduction in Jeju island which is rich in renewable energy resources and will produces green hydrogen using a water electrolysis systems. In order to check durability of long-term operation, AST(accelerated stress test) was applied and the power pattern based on Jeju Island's wind power was applied. After 800 hours of repeated application of low current and high current, the performance of the PEM water electrolysis cell was reduced by up to 10% and by about 5.5% in operating conditions. As the result of impedance analysis, it can be seen that the electrode polarization resistance greatly increased than ohmic polarization resistance. In addition, when the durability evaluation was conducted by applying the wind power pattern of Jeju Island, the performance of the PEM water electrolysis cell showed up to 1.6% and a decrease of less than 1% in operating conditions. As a result of the impedance, it can be seen that the change of ohmic resistance and electrode polarization resistance is small.

A Study on the Safety Job Procedures for Alkaline Water Electrolysis Facilities Based on Renewable Energy (재생에너지 기반 알칼라인 수전해설비의 안전작업절차 방안 연구)

  • Doo-Hyoun Seo;Tae-Hun Kim;Kwang-Won Rhie;Seong-Chul Hong;Hyun-Gi Kim
    • Journal of the Korean Institute of Gas
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    • v.28 no.1
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    • pp.27-34
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    • 2024
  • In accordance with the clean hydrogen-centered hydrogen industry development plan, technology development and demonstration operation of water electrolysis devices are being actively carried out. Risk assessments are performed on newly developed hydrogen-using facilities and supplies to identify potential hazard factors. However, in general, most industrial accidents are caused by operator's human error or incorrect work practices. Additionally, the possibility of accidents occurring during operation control, maintenance, and inspection increases. For this reason, for equipment developed for demonstration operation, the correct work methods for the main jobs of operator must be reviewed and work procedures must be prepared. Accordingly, in this study, we conducted a job safety analysis (JSA) on major jobs in the operation of water electrolysis facilities to study safe work methods and necessary measures.

Effect of Distilled Water Supply Method on Performance of PEMWE Typed Hydrogen Generators for Inhalation (흡입용 PEMWE형 수소 발생기에서 증류수 공급 방법이 성능에 미치는 영향)

  • In-Soo, You;Hyunwoo, Bae;Joon Hyun, Kim;Jaeyong, Sung
    • Journal of the Korean Society of Visualization
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    • v.20 no.3
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    • pp.117-127
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    • 2022
  • The present study has investigated the performance of hydrogen gas generators for inhalation purposes based on polyelectrolyte membrane water electrolysis (PEMWE). The system applied two watering methods. One is pumped water (pumping system) and the other is gravity-fed water without a pump (non-pumping system). The cell efficiencies were compared by measuring the cell voltage and temperature in the hydrogen gas generator, respectively. The results show that the cell voltage and temperature increase with the cell current. The cell temperature is lower in the pumping system than that in the non-pumping system at a given cell current. Even though the amount of hydrogen production is the same regardless of the pumping system, the cell efficiency of the hydrogen gas generator in the non-pumping system is better than that in the pumping system.

Study on the Improvement of Electrochemical Performance by Controlling the Surface Characteristics of the Oxygen Electrode Porous Transport Layer for Proton Exchange Membrane Water Electrolysis (양이온 교환막 수전해용 산화전극 확산층의 표면 특성 제어를 통한 전기화학적 성능 개선 연구)

  • Lee, Han Eol;Linh, Doan Tuan;Lee, Woo-kum;Kim, Taekeun
    • Applied Chemistry for Engineering
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    • v.32 no.3
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    • pp.332-339
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    • 2021
  • Recently, due to concerns about the depletion of fossil fuels and the emission of greenhouse gases, the importance of hydrogen energy technology, which is a clean energy source that does not emit greenhouse gases, is being emphasized. Water electrolysis technology is a green hydrogen technology that obtains hydrogen by electrolyzing water and is attracting attention as one of the ultimate clean future energy resources. In this study, the surface properties of the porous transport layer (PTL), one of the cell components of the proton exchange membrane water electrolysis (PEMWE), were controlled using a sandpaper to reduce overvoltage and increase performance and stability. The surfaces of PTL were sanded using sandpapers of 400, 180, and 100 grit, and then all samples were finally treated with the sandpaper of 1000 grit. The prepared PTL was analyzed for the degree of hydrophilicity by measuring the water contact angle, and the surface shape was observed through SEM analysis. In order to analyze the electrochemical characteristics, I-V performance curves and impedance measurements were conducted.