• Title/Summary/Keyword: Oxygen Evolution Catalyst

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Synthesis of Fe-doped β-Ni(OH)2 microcrystals and their oxygen evolution reactions (Fe 도핑된 β-Ni(OH)2 마이크로결정 합성과 산소발생반응 특성)

  • Je Hong Park;Si Beom Yu;Seungwon Jeong;Byeong Jun Kim;Kang Min Kim;Jeong Ho Ryu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.5
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    • pp.196-201
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    • 2023
  • In order to improve the efficiency of the water splitting system for hydrogen energy production, the high overvoltage in the electrochemical reaction caused by the catalyst in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be reduced. Among them, transition metal-based compounds (hydroxide, sulfide, etc.) are attracting attention as catalyst materials to replace currently used precious metals such as platinum. In this study, Ni foam, an inexpensive metal porous material, was used as a support and β-Ni(OH)2 microcrystals were synthesized through a hydrothermal synthesis process. In addition, changes in the crystal morphology, crystal structure, and water splitting characteristics of β-Ni(OH)2 microcrystals synthesized by doping Fe to improve electrochemical properties were observed, and applicability as a catalyst in a commercial water electrolysis system was examined.

Effects of Mo co-doping into Fe doped β-Ni(OH)2 microcrystals for oxygen evolution reactions (Fe-doped β-Ni(OH)2의 산소발생반응 증가를 위한 Mo의 동시도핑효과)

  • Je Hong Park;Si Beom Yu;Tae Kwang An;Byeong Jun Kim;Jeong Ho Ryu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.34 no.1
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    • pp.30-35
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    • 2024
  • In order to improve the efficiency of the water splitting system for hydrogen production, the high overvoltage in the electrochemical reaction caused by the catalyst in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be reduced. Among them, transition metal-based compounds are attracting attention as catalyst materials that can replace precious metals such as platinum that are currently used. In this study, nickel foam, an inexpensive metal porous material, was used as a support, and Fe-doped β-Ni(OH)2 microcrystals were synthesized through a hydrothermal synthesis process. In addition, in order to improve OER properties, changes in the shape, crystal structure, and water splitting characteristics of Fe-Mo co-doped β-Ni(OH)2 microcrystals synthesized by co-doping with Mo were observed. The changes in the shape, crystal structure, and applicability as a catalyst for water splitting were examined.

The Role of Metal Catalyst on Water Permeation and Stability of BaCe0.8Y0.2O3-δ

  • Al, S.;Zhang, G.
    • Journal of Electrochemical Science and Technology
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    • v.9 no.3
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    • pp.212-219
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    • 2018
  • Perovskite type ceramic membranes which exhibit dual ion conduction (proton and oxygen ion conduction) can permeate water and can aid solving operational problems such as temperature gradient and carbon deposition associated with a working solid oxide fuel cell. From this point of view, it is crucial to reveal water transport mechanism and especially the nature of the surface sites that is necessary for water incorporation and evolution. $BaCe_{0.8}Y_{0.2}O_{3-{\alpha}}$ (BCY20) was used as a model proton and oxygen ion conducting membrane in this work. Four different catalytically modified membrane configurations were used for the investigations and water flux was measured as a function of temperature. In addition, CO was introduced to the permeate side in order to test the stability of membrane against water and $CO/CO_2$ and post operation analysis of used membranes were carried out. The results revealed that water incorporation occurs on any exposed electrolyte surface. However, the magnitude of water permeation changes depending on which membrane surface is catalytically modified. The platinum increases the water flux on the feed side whilst it decreases the flux on the permeate side. Water flux measurements suggest that platinum can block water permeation on the permeate side by reducing the access to the lattice oxygen in the surface layer.

The Effect of Adsorbed Oxygen Species on the Partial Oxidation of Ethylene over Ag/α-Al2O3 (Ag/α-Al2O3 촉매상에서의 에틸렌 부분산화반응에 미치는 흡착산소종의 영향)

  • Baik, Choong-Hoon;Lee, Sang-Gi;Yeo, Jong-Kee;Lee, Ho-In
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.609-615
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    • 1994
  • Partial oxidation of ethylene over 10wt% $Ag/{\alpha}-Al_2O_3$ catalyst was studied with a pulse reactor which was connected directly to a G. C. When ethylene was injected after oxygen injection at the temperature where molecular adsorption of oxygen is difficult ethylene oxide was evolved. From the results, it is suggested that adsorbed atomic oxygen is related with the evolution of ethylene oxide. The selectivity to ethylene oxide decreased with the decrease of the amounts of adsorbed oxygen and bulk oxygen. Ethylene oxide was either decomposed to ethylene and adsorbed oxygen or isomerized to acetaldehyde. However, the isomerization of ethylene oxide to acetaldehyde was strongly suppressed by the preadsorbed oxygen.

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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
    • Transactions of the Korean hydrogen and new energy society
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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.

Development of catalyst-substrate integrated copper cobalt oxide electrode using electrodeposition for anion exchange membrane water electrolysis (전착법을 이용한 촉매-기판 일체형 구리 코발트 산화물 전극 개발 및 음이온 교환막 수전해 적용)

  • Kim, Dohyung;Kim, Geul Han;Choi, Sung Mook;Lee, Ji-hoon;Jung, Jaehoon;Lee, Kyung-Bok;Yang, Juchan
    • Journal of the Korean institute of surface engineering
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    • v.55 no.3
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    • pp.180-186
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    • 2022
  • The production of hydrogen via water electrolysis (i.e., green hydrogen) using renewable energy is key to the development of a sustainable society. However, most current electrocatalysts are based on expensive precious metals and require the use of highly purified water in the electrolyte. We demonstrated the preparation of a non-precious metal catalyst based on CuCo2O4 (CCO) via simple electrodeposition. Further, an optimization process for electrodeposition potential, solution concentration and electrodeposition method was develop for a catalyst-substrate integrated electrode, which indicated the highly electrocatalytic performance of the material in electrochemical tests and when applied to an anion exchange membrane water electrolyzer.

Study on Catalytic Activity of the Selective CO Oxidation and Characterization Using $La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ Perovskite Catalysts ($La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ Perovskite촉매의 선택적 CO 산화반응 및 특성 분석에 관한 연구)

  • Sohn, Jung-Min
    • Transactions of the Korean hydrogen and new energy society
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    • v.18 no.2
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    • pp.116-123
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    • 2007
  • [ $La_{0.5}Ce_{0.5}Co_{1-x}Cu_xO_{3-{\alpha}}$ ](X=0, 0.1, 0.3, 0.5) perovskites were prepared by coprecipitation method at pH 7 or pH 11 and its catalytic activity of selective CO oxidation was investigated. The characteristics of these catalysts were analyzed by $N_2$ adsorption, X-ray diffraction(XRD), SEM, $O_2$-temperature programmed desorption(TPD). The pH value at a preparation step made effect on particle morphology. The smaller particle was obtained with a condition of pH 7. The better catalytic activity was observed using catalysts prepared at pH 7 than pH 11. The maximum CO conversion of 98% was observed over $La_{0.5}Ce_{0.5}Co_{0.7}Cu_{0.3}O_{3-{\alpha}}$ at $320^{\circ}C$. Below $200^{\circ}C$, the most active catalyst was $La_{0.5}Ce_{0.5}Co_{0.9}Cu_{0.1}O_{3-{\alpha}}$, of which conversion was 92% at $200^{\circ}C$. By the substitution of Cu, the evolution of ${\alpha}$-oxygen was remarkably enhanced regardless of pH value at preparation step according to $O_2$-TPD. Among the different ${\alpha}$-oxygen species, the oxygen species evolved between $400^{\circ}C$ and $500^{\circ}C$, gave the better catalytic performance for selective CO oxidation including $La_{0.5}Ce_{0.5}CoO_3$ in which Cu was absent.

Synthesis of Co3O4 Nanocubes as an Efficient Electrocatalysts for the Oxygen Evolution Reacitons (물 분해 과정에서 효율적인 촉매 특성을 보이는 Co3O4 nanocubes 합성)

  • Choi, Hyung Wook;Jeong, Dong In;Wu, Shengyuan;Kumar, Mohit;Kang, Bong Kyun;Yang, Woo Seok;Yoon, Dae Ho
    • Composites Research
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    • v.32 no.6
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    • pp.355-359
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    • 2019
  • The high efficient water splitting system should involve the reduction of high overpotential value, which was enhanced by the electrocatalytic reaction efficiency of catalysts, during the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) reaction, respectively. Among them, transition metal-based compounds (oxides, sulfides, phosphides, and nitrides) are attracting attention as catalyst materials to replace noble metals that are currently commercially available. Herein, we synthesized optimal monodisperse Co3[Co(CN)6]2 PBAs by FESEM, and confirmed crystallinity by XRD and FT-IR, and thermal behavior of PBAs via TG-DTA. Also, we synthesized monodispersed Co3O4 nanocubes by calcination of Co3[Co(CN)6]2 PBAs, confirmed the crystallinity by XRD, and proceeded OER measurement. Finally, the synthesized Co3O4 nanocubes showed a low overpotential of 312 mV at a current density of 10 mA·cm-2 with a low Tafel plot (96.6 mV·dec-1).

NiFeOx co-catalyzed BiVO4 photoanode for improved photoelectrochemical water splitting

  • Kim, Jin Hyun;Kang, Hyun Joon;Magesh, Ganesan;Lee, Jae Sung
    • Rapid Communication in Photoscience
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    • v.3 no.2
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    • pp.35-37
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    • 2014
  • PEC (photoelectrochemical) water splitting for $O_2/H_2$ production is one of the promising but difficult way to utilize solar energy. Among photocatalytic materials for PEC water oxidation, $BiVO_4$ (Eg = 2.4 eV) has been recently intensively studied since it has various advantageous properties. But its maximum efficiency has not been realized owing to kinetic factors - slow water oxidation at surface & insufficient stability. These problems can be simultaneously solved by application of oxygen evolution catalyst (OEC) such as $CoO_x$, Co-Pi, $IrO_x$ etc. Herein we report the first successful application of $NiFeO_x$ OEC on $BiVO_4$, showing good performance compared to other effective OEC applied on $BiVO_4$ under basic conditions. The enhanced activity of OEC loaded $BiVO_4$ has been supported by the surface charge separation efficiency and electrochemical impedance studies.

Can Artificial Intelligence Boost Developing Electrocatalysts for Efficient Water Splitting to Produce Green Hydrogen?

  • Jaehyun Kim;Ho Won Jang
    • Korean Journal of Materials Research
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    • v.33 no.5
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    • pp.175-188
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    • 2023
  • Water electrolysis holds great potential as a method for producing renewable hydrogen fuel at large-scale, and to replace the fossil fuels responsible for greenhouse gases emissions and global climate change. To reduce the cost of hydrogen and make it competitive against fossil fuels, the efficiency of green hydrogen production should be maximized. This requires superior electrocatalysts to reduce the reaction energy barriers. The development of catalytic materials has mostly relied on empirical, trial-and-error methods because of the complicated, multidimensional, and dynamic nature of catalysis, requiring significant time and effort to find optimized multicomponent catalysts under a variety of reaction conditions. The ultimate goal for all researchers in the materials science and engineering field is the rational and efficient design of materials with desired performance. Discovering and understanding new catalysts with desired properties is at the heart of materials science research. This process can benefit from machine learning (ML), given the complex nature of catalytic reactions and vast range of candidate materials. This review summarizes recent achievements in catalysts discovery for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The basic concepts of ML algorithms and practical guides for materials scientists are also demonstrated. The challenges and strategies of applying ML are discussed, which should be collaboratively addressed by materials scientists and ML communities. The ultimate integration of ML in catalyst development is expected to accelerate the design, discovery, optimization, and interpretation of superior electrocatalysts, to realize a carbon-free ecosystem based on green hydrogen.