• 제목/요약/키워드: Oxygen Evolution Catalyst

검색결과 45건 처리시간 0.032초

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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    • 제10권1호
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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.

아연공기이차전지용 La1-xSrxCoO3 양극촉매의 제조 및 이를 적용한 양극의 전기화학적 특성연구 (Synthesis and Electrochemical Evaluation of La1-xSrxCoO3 Cathode Material for Zinc Air Secondary Batteries Application)

  • 엄승욱;선양국
    • 한국전기전자재료학회논문지
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    • 제21권5호
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    • pp.447-452
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    • 2008
  • We synthesized nano-sized $La_{1-x}Sr_xCoO_3$ ($x=0.1{\sim}0.4$) cathode catalyst for the zinc air secondary batteries by citrate method, And we measured the cathode's electrochemical characteristics according to content of strontium compose the cathode catalyst. We controlled the pH of precursor solution by 10 in the process of manufacturing the precursor, We heat treated the prepared precursor at various calcination temperature ($500{\sim}900^{\circ}C$), and examined the optimum calcinations temperature by XRD analysis and electrochemical evaluation. We examined the ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) performance of the prepared $La_{1-x}Sr_xCoO_3$ catalyst powder. When we consider ORR and OER performance simultaneously, $La_{0.7}Sr_{0.3}CoO_3$ catalyst has shown the best performance because of its lowest voltage deference between charge and discharge.

Synergistically Enhanced Oxygen Evolution Catalysis with Surface Modified Halloysite Nanotube

  • Hyeongwon Jeong;Bharat Sharma;Jae-ha Myung
    • Journal of Electrochemical Science and Technology
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    • 제14권1호
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    • pp.96-104
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    • 2023
  • Synergistically increased oxygen evolution reaction (OER) of manganese oxide (MnO2) catalyst is introduced with surface-modified halloysite nanotube (Fe3O4-HNTs) structure. The flake shaped MnO2 catalyst is attached on the nanotube template (Fe3O4-HNTs) by series of wet chemical and hydrothermal method. The strong interaction between MnO2 and Fe3O4-HNTs maximized active surface area and inter-connectivity for festinate charge transfer reaction for OER. The synergistical effect between Fe3O4 layer and MnO2 catalyst enhance the Mn3+/Mn4+ ratio by partial replacement of Mn ions with Fe. The relatively increased Mn3+/Mn4+ ratio on MnO2@FHNTs induced 𝜎* orbital (eg) occupation close to single electron, improving the OER performances. The MnO2@FHNTs catalyst exhibited the reduced overpotential of 0.42 V (E vs. RHE) at 10 mA/cm2 and Tafel slope of (99 mV/dec), compared with that of MnO2 with unmodified HNTs (0.65 V, 219 mV/dec) and pristine MnO2 (0.53 V, 205 mV/dec). The present study provides simple and innovative method to fabricate nano fiberized OER catalyst for a broad application of energy conversion and storage systems.

수전해용 Ir/TiO2 산소 발생 촉매의 제조 및 성능 평가 (Synthesis and Evaluation of Ir/TiO2 OER catalyst for PEM water electrolysis)

  • 송민아;정혜영;이해지;최윤기;문상봉
    • 한국수소및신에너지학회논문집
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    • 제27권5호
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    • pp.471-477
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    • 2016
  • In this research, the Ir supported $TiO_2$ (P25) catalyst was prepared by precipitation method for oxygen evolution reaction. The $Ir/TiO_2$ catalyst was synthesised by reduction reaction using reducing agent. Physiochemical characterizations of synthesized $Ir/TiO_2$ catalyst was studied by means of SEM, EDS mapping, TEM and XRD. The Electrochemical characterizations were tested by using the technique of CV and LSV by RDE and Potentiostat. Physicochemical properties were characterized with XRD where Iridium metal morphology and Ir(111) and Ir(222) peaks were founded. $Ir0.2Ru0.8O_2$ exhibited higher OER activity than $Ir0.5Ru0.5O_2$ followed by $Ir/TiO_2$ and $IrO_2$.

전기화학적 물 분해 시스템에서 산소발생반응을 위한 Co와 Mo 기반 촉매의 최근 연구 동향 (Research on Co- and Mo-Based Catalysts for the Oxygen Evolution Reaction in Electrochemical Water Splitting System)

  • 박준성;정원석;부종찬
    • 전기화학회지
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    • 제26권4호
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    • pp.64-70
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    • 2023
  • 급격한 온실가스 배출량 증가로 인해 지구 온난화가 심화되고 있다. 이로 인해 탄소중립의 필요성과 이행이 더욱 절실해졌다. 이를 위해 여러 가지 신재생에너지 중 수소에 대한 관심이 부각되고 있다. 수소는 지구 상에 풍부한 자원이며 무탄소 전원으로 친환경적이다. 궁극적으로 물의 전기분해에 의해 친환경 수소를 얻을 수 있다. 하지만 산소 발생 반응에 사용되는 촉매는 고가이며 희귀하고 촉매의 내구성에 문제가 있어 어려움을 겪고 있기 때문에 비귀금속 촉매의 개발이 필요하다. 본 총설에서는 최근 발표된 산소 발생 촉매 중 비귀금속 촉매인 Co와 Mo 기반의 촉매를 정리, 요약하여 소개하고 있다. 이를 통해 비귀금속 촉매의 활성과 내구성을 증가시키기 위한 촉매의 특성 설계를 이해하는 데 도움이 될 것이다.

Effect of Cobalt Loading on the Performance and Stability of Oxygen Reduction and Evolution Reactions in Rechargeable Zinc-air Batteries

  • Sheraz Ahmed;Joongpyo Shim;Gyungse Park
    • 대한화학회지
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    • 제68권2호
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    • pp.87-92
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    • 2024
  • The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.

Contribution of Carbon Dot Nanoparticles in Electrocatalysis: Development in Energy Conversion Process

  • Jana, Jayasmita;Ngo, Yen-Linh Thi;Chung, Jin Suk;Hur, Seung Hyun
    • Journal of Electrochemical Science and Technology
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    • 제11권3호
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    • pp.220-237
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    • 2020
  • Modern electrochemical energy devices involve generation and reduction of fuel gases through electrochemical reactions of water splitting, alcohol oxidation, oxygen reduction, etc. Initially, these processes were executed in the presence of noble metal-based catalyst that showed low overpotential and high current density. However, its high cost, unavailability, corrosion and related toxicity limited its application. The search for alternative with high stability, durability, and efficiency led scientists towards carbon nanoparticles supported catalysts which has high surface area, good electrical conductivity, tunable morphology, low cost, ease of synthesis and stability. Carbon nanoparticles are classified into two groups based on morphology, one and zero dimensional particles. Carbon nanoparticles at zero dimension, denoted as carbon dots, are less used carbon support compared to other forms. However, recently carbon dots with improved electronic properties have become popular as catalyst as well as catalyst support. This review focused on the recent advances in electrocatalytic activities of carbon dots. The mechanisms of common electrocatalytic reactions and the role of the catalysts are also discussed. The review also proposed future developments and other research directions to overcome current limitations.

Size Effects of MoS2 on Hydrogen and Oxygen Evolution Reaction

  • Ghanashyam, Gyawali;Jeong, Hae Kyung
    • Journal of Electrochemical Science and Technology
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    • 제13권1호
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    • pp.120-127
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    • 2022
  • Molybdenum disulfide (MoS2) has been widely used as a catalyst for the bifunctional activities of hydrogen and oxygen evolution reactions (HER and OER). Here, we investigated size dependent HER and OER performance of MoS2. The smallest size (90 nm) of MoS2 exhibits the lowest overpotential of -0.28 V at -10 mAcm-2 and 1.52 V at 300 mAcm-2 with the smallest Tafel slopes of 151 and 176 mVdec-1 for HER and OER, respectively, compared to bigger sizes (2 ㎛ and 6 ㎛) of MoS2. The better HER and OER performance is attributed to high electrochemical active surface area (6 × 10-4 cm2) with edge sites and low charge transfer resistance (18.1 Ω), confirming that the smaller MoS2 nanosheets have the better catalytic behavior.

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

  • 이진구
    • 세라미스트
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    • 제22권2호
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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.

내구성 향상을 위한 연료전지 촉매 개발 (Synthesis and Durability of Carbon-Supported Catalysts for PEMFC)

  • 이미혜;최진성;노범욱
    • 한국수소및신에너지학회논문집
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    • 제26권4호
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    • pp.318-323
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    • 2015
  • For commercialization of fuel cell electric vehicles, one of the key objectives is to improve durability of MEA and electrocatalysts. Regarding electrocatalysts, the major issue is to reduce carbon corrosion and dissolution of Pt caused by harsh conditions, for example, SU/SD (Start-up/Shut-down). In this research, OER (Oxygen Evolution Reaction) catalyst has been developed improvement of durability. A modified polyol process is developed by controlling the pH of the solvent to synthesize the PtIr nanocatalysts on carbon supports. Each performance of the MEAs applying PtIr and Pt are equivalent because PtIrnanocatalysts have both ORR and OER activity. Breadboard test for catalyst durability in harsh conditions and high potentialsis found that the MEA applying PtIrnanocatalysts durability is improved more than the MEA applying Pt nanocatalysts.