• Title/Summary/Keyword: Oxygen Evolution Catalyst

Search Result 45, Processing Time 0.024 seconds

Micro Emulsion Synthesis of LaCoO3 Nanoparticles and their Electrochemical Catalytic Activity

  • Islam, Mobinul;Jeong, Min-Gi;Ghani, Faizan;Jung, Hun-Gi
    • Journal of Electrochemical Science and Technology
    • /
    • v.6 no.4
    • /
    • pp.121-130
    • /
    • 2015
  • The micro emulsion method has been successfully used for preparing perovskite LaCoO3 with uniform, fine-shaped nanoparticles showing high activity as electro catalysts in oxygen reduction reactions (ORRs). They are, therefore, promising candidates for the air-cathode in metal-air rechargeable batteries. Since the activity of a catalyst is highly dependent on its specific surface area, nanoparticles of the perovskite catalyst are desirable for catalyzing both oxygen reduction and evolution reactions. Herein, LaCoO3 powder was also prepared by sol-gel method for comparison, with a broad particle distribution and high agglomeration. The electro catalytic properties of LaCoO3 and LaCoO3-carbon Super P mixture layers toward the ORR were studied comparatively using the rotating disk electrode technique in 0.1 M KOH electrolyte to elucidate the effect of carbon Super P. Koutecky-Levich theory was applied to acquire the overall electron transfer number (n) during the ORR, calculated to be ~3.74 for the LaCoO3-Super P mixture, quite close to the theoretical value (4.0), and ~2.7 for carbon-free LaCoO3. A synergistic effect toward the ORR is observed when carbon is present in the LaCoO3 layer. Carbon is assumed to be more than an additive, enhancing the electronic conductivity of the oxide catalyst. It is suggested that ORRs, catalyzed by the LaCoO3-Super P mixture, are dominated by a 2+2-electron transfer pathway to form the final, hydroxyl ion product.

Recent Advances in Catalyst Materials for PEM Water Electrolysis

  • Paula Marielle Ababao;Ilwhan Oh
    • Journal of the Korean Electrochemical Society
    • /
    • v.26 no.2
    • /
    • pp.19-34
    • /
    • 2023
  • Due to the intermittency of renewable energy sources, a need to store and transport energy will increase. Hydrogen production through water electrolysis will provide an excellent way to supplement the intermittency of renewable energy sources. While alkaline water electrolysis is currently the most mature technology, it has drawbacks of low current density, large footprint, gas crossover, etc. The PEM water electrolysis has potential to replace the alkaline electrolysis. However, expensive catalyst material used in the PEM electrolysis has been the bottleneck of widespread use. In this review, we have reviewed recent efforts to reduce catalyst loading in PEM water electrolysis. In core-shell nanostructures, the precious metal catalyst forms a shell while heteroatoms form a core. In this way, the catalyst loading can be significantly reduced while maintaining the catalytic activity. In another approach, a corrosion-resistant support is utilized, which provides a stable platform to impregnate precious metal catalyst.

Effect of Sulfurization on SILAR Synthesized Cobalt Phosphate Hydrate Nanosheets for Oxygen Evolution Reaction

  • Kamble, Girish;Malavekar, Dhanaji;Jang, Suyoung;Kim, Jin Hyeok
    • Korean Journal of Materials Research
    • /
    • v.32 no.10
    • /
    • pp.408-413
    • /
    • 2022
  • The oxygen evolution reaction (OER) is very sluggish compared to the hydrogen evolution reaction (HER). Considering this difference is essential when designing and developing a cost-effective and facile synthesis method for a catalyst that can effectively perform OER activity. The material should possess a high surface area and more active sites. Considering these points, in this work we successfully synthesized sheets of cobalt phosphate hydrate (CP) and sulphurated cobalt phosphate hydrate (CPS) material, using simple successive ionic layered adsorption and reaction (SILAR) methods followed by sulfurization. The CP and CPS electrodes exhibited overpotentials of 279 mV with a Tafel slope of 212 mV dec-1 and 381 mV with a Tafel slope of 212 mV dec-1, respectively. The superior performance after sulfurization is attributed to the intrinsic activity of the deposited well-aligned nanosheet structures, which provided a substantial number of electrochemically active surface sites, speeded electron transfer, and at the same time improved the diffusion of the electrolyte.

Electrochemical Analysis of CuxCo3-xO4 Catalyst for Oxygen Evolution Reaction Prepared by Sol-Gel Method (Sol-Gel법을 이용한 CuxCo3-xO4 산소 발생 촉매의 합성 및 전기화학 특성 분석)

  • Park, Yoo Sei;Jung, Changwook;Kim, Chiho;Koo, Taewoo;Seok, Changgyu;Kwon, Ilyeong;Kim, Yangdo
    • Korean Journal of Materials Research
    • /
    • v.29 no.2
    • /
    • pp.92-96
    • /
    • 2019
  • Transition metal oxide is widely used as a water electrolysis catalyst to substitute for a noble metal catalyst such as $IrO_2$ and $RuO_2$. In this study, the sol-gel method is used to synthesize the $Cu_xCo_{3-x}O_4$ catalyst for the oxygen evolution reaction (OER),. The CuxCo3-xO4 is synthesized at various calcination temperatures from $250^{\circ}C$ to $400^{\circ}C$ for 4 h. The $Cu_xCo_{3-x}O_4$ synthesized at $300^{\circ}C$ has a perfect spinel structure without residues of the precursor and secondary phases, such as CuO. The particle size of $Cu_xCo_{3-x}O_4$ increases with an increase in calcination temperature. Amongst all the samples studied, $Cu_xCo_{3-x}O_4$, which is synthesized at 300?, has the highest activity for the OER. Its onset potential for the OER is 370 mV and the overpotential at $10mA/cm^2$ is 438 mV. The tafel slope of $Cu_xCo_{3-x}O_4$ synthesized at $300^{\circ}C$ has a low value of 58 mV/dec. These results are mainly explained by the increase in the available active surface area of the $Cu_xCo_{3-x}O_4$ catalyst.

Synthesis and Characterization of CuCo2O4 Nanofiber Electrocatalyst for Oxygen Evolution Reaction (산소발생반응을 위한 CuCo2O4 나노섬유 전기화학 촉매 합성 및 특성 분석)

  • Won, Mi So;Jang, Myeong-Je;Lee, Kyu Hwan;Kim, Yang Do;Choi, Sung Mook
    • Journal of the Korean institute of surface engineering
    • /
    • v.49 no.6
    • /
    • pp.539-548
    • /
    • 2016
  • The non-noble 1D nanofibers(NFs) prepared by electrospinning and calcination method were used as oxygen evolution reaction (OER) electrocatalyst for water electrolysis. The electrospinning process and rate of solution composition was optimized to prepare uniform and non-beaded PVP polymer electrospun NFs. The diameter and morphology of PVP NFs changed in accordance with the viscosity and ion conductivity. The clean metal precursor contained electrospun fibers were synthesized via the optimized electrospinning process and solution composition. The calcined $CuCo_2O_4$ NFs catalyst showed higher activity and long-term cycle stability for OER compared with other $Co_3O_4$, $NiCo_2O$ NF catalysts. Furthermore, the $CuCo_2O_4$ NFs maintained the OER activity during long-term cycle test compared with commercial $CuCo_2O_4$ nanoparticle catalyst due to unique physicochemical and electrochemical properties by1D nanostructure.

Synthesis of RuO2/h-Co3O4 Electrocatalysts Derived from Hollow ZIF and Their Applications for Oxygen Evolution Reaction (중공 ZIF를 이용한 RuO2/h-Co3O4 촉매의 합성 및 산소 발생 반응으로의 활용)

  • Yoonmo Koo;Youngbin Lee;Kyungmin Im;Jinsoo Kim
    • Applied Chemistry for Engineering
    • /
    • v.34 no.2
    • /
    • pp.180-185
    • /
    • 2023
  • To improve the efficiency of water electrolysis, it is essential to develop an oxygen evolution reaction (OER) electrocatalyst with high performance and long-term stability, accelerating the reaction rate of OER. In this study, a hollow metal-organic framework (MOF)-derived ruthenium-cobalt oxide catalyst was developed to synthesize an efficient OER electrocatalyst. As the synthesized catalyst increases the surface exposure of ruthenium, a low overpotential (386 mV) was observed at a current density of 10 mA/cm2 with a low Tafel slope. It is expected to be able to replace noble metal catalysts by showing higher mass activity and stability than commercial RuO2 catalysts.

Investigating adsorption ion characteristics on cobalt oxides catalyst in electrolysis of waste alkaline solutions using ab-initio study (제일원리 전산모사법을 이용한 폐양액 수전해용 코발트 산화물 촉매의 흡착 이온 특성 연구)

  • Juwan Woo;Jong Min Lee;MinHo Seo
    • Journal of the Korean institute of surface engineering
    • /
    • v.56 no.6
    • /
    • pp.427-436
    • /
    • 2023
  • In the industry, it is recognized that human activities significantly lead to a large amount of wastewater, mainly due to the increased use of water and energy. As a result, the growing field of wastewater resource technology is getting more attention. The common technology for hydrogen production, water electrolysis, requires purified water, leading to the need for desalination and reprocessing. However, producing hydrogen directly from wastewater could be a more cost-effective option compared to traditional methods. To achieve this, a series of first-principle computational simulations were conducted to assess how waste nutrient ions affect standard electrolysis catalysts. This study focused on understanding the adsorption mechanisms of byproducts related to the oxygen evolution reaction (OER) in anion exchange membrane (AEM) electrolysis, using Co3O4 as a typical non-precious metal catalyst. At the same time, efforts were made to develop a comprehensive free energy prediction model for more accurate predictions of OER results.

Electrocatalysis of Selective Chlorine Evolution Reaction: Fundamental Understanding and Catalyst Design

  • Taejung Lim;Jinjong Kim;Sang Hoon Joo
    • Journal of Electrochemical Science and Technology
    • /
    • v.14 no.2
    • /
    • pp.105-119
    • /
    • 2023
  • The electrochemical chlorine evolution reaction (CER) is an important electrochemical reaction and has been widely used in chlor-alkali electrolysis, on-site generation of ClO-, and Cl2-mediated electrosynthesis. Although precious metal-based mixed metal oxides (MMOs) have been used as CER catalysts for more than half a century, they intrinsically suffer from a selectivity problem between the CER and parasitic oxygen evolution reaction (OER). Hence, the design of selective CER electrocatalysts is critically important. In this review, we provide an overview of the fundamental issues related to the electrocatalysis of the CER and design strategies for selective CER electrocatalysts. We present experimental and theoretical methods for assessing the active sites of MMO catalysts and the origin of the scaling relationship between the CER and the OER. We discuss kinetic analysis methods to understand the kinetics and mechanisms of CER. Next, we summarize the design strategies for new CER electrocatalysts that can enhance the reactivity of MMO-based catalysts and overcome their scaling relationship, which include the doping of MMO catalysts with foreign metals and the development of non-precious metal-based catalysts and atomically dispersed metal catalysts.

Characterization of LaCoO3 Perovskite Catalyst for Oxygen Reduction Reaction in Zn-air Rechargeable Batteries (아연-공기전지용 페롭스카이트 산화물 촉매의 산소환원반응 특성)

  • Sun, Ho-Jung;Cho, Myung-Yeon;An, Jung-Chul;Eom, Seungwook;Park, Gyungse;Shim, Joongpyo
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.25 no.4
    • /
    • pp.436-442
    • /
    • 2014
  • $LaCoO_3$ powders synthesized by Pechini process were pulverized by planetary ball-milling to decrease particle size and characterized as a catalyst in alkaline solution for oxygen reduction and evolution reaction (ORR & OER). The changes of physical properties, such as particle size distribution, surface area and electric conductivity, were analyzed as a function of ball-milling time. Also, the variations of the crystal structure and surface morphology of ball-milled powders were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemically catalytic activities of the intrinsic $LaCoO_3$ powders decreased with increasing ball-milling time, but their electrochemical performance as an electrode improved by the increase of the surface area of the powder.

Synthesis of CoFe2O4 Nanoparticles as Electrocatalyst for Oxygen Evolution Reaction (산소 발생 반응 용 전기화학촉매로 사용되는 CoFe2O4 나노 입자 합성 및 특성 분석)

  • Lee, Jooyoung;Kim, Geulhan;Yang, Juchan;Park, Yoo Sei;Jang, Myeong Je;Choi, Sung Mook
    • Journal of the Korean Electrochemical Society
    • /
    • v.23 no.4
    • /
    • pp.97-104
    • /
    • 2020
  • One of the main challenges of electrochemical water splitting technology is to develop a high performance, low cost oxygen-evolving electrode capable of substituting a noble metal catalyst, Ir or Ru based catalyst. In this work, CoFe2O4 nanoparticles with sub-44 nmsize of a inverse spinel structure for oxygen evolution reaction (OER) were synthesized by the injection of KNO3 and NaOH solution to a preheated CoSO4 and Fe(NO3)3 solution. The synthesis time of CoFe2O4 nanoparticles was controlled to control particle and crystallite size. When the synthesis time was 6 h, CoFe2O4 nanoparticles had high conductivity and electrochemical surface area. The overpotential at current denstiy of 10 mA/㎠ and Tafel slope of CoFe2O4 (6h) were 395 mV and 52 mV/dec, respectively. In addition, the catalyst showed excellent durability for 18 hours at 10 mA/㎠.