• Title/Summary/Keyword: Nanostructured electrode

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Preparation of nano composite metal-oxide electrode and its application for superrcapacitor (나노복합산화물 전극의 제조 및 수퍼커패시터로써의 응용)

  • Kim, Hong-Il;Lee, Ju-Won;Kim, Sang-Gil;Yuk, Gyung-Chang;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.801-804
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    • 2002
  • Electrochemical capacitors are becoming attractive energy storage systems particularly for applications involving high power requirements such as hybrid systems consisting of batteries and electrochemical capacitors for electric vehicle propulsion. Both of amorphous cobalt oxide and manganese dioxide were prepared by sol-gel process reported in our previous work. Nanostructured supramolecular oligomer of 1,5-diaminoanthraquinone(DAAQ) coated metal oxides were successfully prepared by electrochemical oxidation from an acidic non-aqueous medium. We established process parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured metal oxide electrodes using controlled solution chemistry. $CoO_2$ and $MnO_2$-based composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency.

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Nanostructured Alloy Electrode for use in Small-Sized Direct Methanol Fuel Cells (소형 직접 메탄올 연료전지를 위한 나노 합금 전극)

  • Park Gyeong Won;Choi Jong Ho;Park In Su;Nam Woo Hyeon;Seong Yeong Eun
    • 한국전기화학회:학술대회논문집
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    • 2003.07a
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    • pp.83-88
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    • 2003
  • PtRu alloy and $PtRu-WO_3$ nanocomposite thin-film electrodes for methanol electrooxidation were fabricated by means of a sputtering method. The structural and electrochemical properties of well-defined PtRu alloy thin-film electrodes were characterized using X-ray diffraction, Rutherford backscattering spectroscopy. X-ray photoelectron spectroscopy, and electrochemical measurements. The alloy thin-film electrodes were classified as follows: Pt-based and Ru-based alloy structure. Based on structural and electrochemical understanding of the PtRu alloy thin-film electrodes, the well-controlled physical and (electro)chemical properties of $PtRu-WO_3$, showed superior specific current to that of a nanosized PtRu alloy catalyst, The homogeneous dispersion of alloy catalyst and well-formed nanophase structure would lead to an excellent catalytic electrode reaction for high-performance fuel cells. In addition, the enhanced catalytic activity in nanocomposite electrode was found to be closely related to proton transfer in tungsten oxide using in-situ electrochemical transmittance measurement.

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Fabrication of Gold Nanostructures Using Electrochemical Deposition Integrated with Solution Process (용액 공정을 접목한 전기화학 증착 기법을 활용한 금 나노 구조체 제작)

  • Jihee Kim;Donghyeon Kim;Mijeong Kang
    • Journal of the Korean Electrochemical Society
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    • v.27 no.3
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    • pp.81-87
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    • 2024
  • Nanomaterial electrodes are used to improve the analytical performances of electrochemical measurements in biological and chemical field. Frequently used methods for fabricating metal nanostructures are solution processing and electrodeposition. In the solution process, it is possible to control the characteristics (e.g., direction) of metal growth by using capping agents, thereby fabricating nanoparticles of specific structures. In the electrodeposition, the electrode surface and the deposited metal atoms are in direct contact. Each process has its own limitation as well, and many studies are conducted to overcome such limitation. In this paper, we report an integration of the two fabrication methods and the characteristics, such as structural and electrochemical properties, of the fabricated electrodes. Lastly, we discuss the possibility of using the fabricated nanostructured electrode as a sensor.

An Electrochemical Sensor for Hydrazine Based on In Situ Grown Cobalt Hexacyanoferrate Nanostructured Film

  • Kang, Inhak;Shin, Woo-seung;Manivannan, Shanmugam;Seo, Yeji;Kim, Kyuwon
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.277-285
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    • 2016
  • There is a growing demand for simple, cost-effective, and accurate analytical tools to determine the concentrations of biological and environmental compounds. In this study, a stable electroactive thin film of cobalt hexacyanoferrate (Cohcf) was prepared as an in situ chemical precipitant using electrostatic adsorption of $Co^{2+}$ on a silicate sol-gel matrix (SSG)-modified indium tin oxide electrode pre-adsorbed with $[Fe(CN)_6]^{3-}$ ions. The modified electrode was characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical techniques. Electrocatalytic oxidation of hydrazine on the modified electrode was studied. An electrochemical sensor for hydrazine was constructed on the SSG-Cohcf-modified electrode. The oxidation peak currents showed a linear relationship with the hydrazine concentration. This study provides insight into the in situ growth and stability behavior of Cohcf nanostructures and has implications for the design and development of advanced electrode materials for fuel cells and sensor applications.

Voltammetric Determination of Droxidopa in the Presence of Tryptophan Using a Nanostructured Base Electrochemical Sensor

  • Yaghoubian, Halimeh;Jahani, Shohreh;Beitollahi, Hadi;tajik, Somayeh;Hosseinzadeh, Rahman;Biparva, Pouria
    • Journal of Electrochemical Science and Technology
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    • v.9 no.2
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    • pp.109-117
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    • 2018
  • A novel carbon paste electrode modified with $Cu-TiO_2$ nanocomposite, 2-(ferrocenylethynyl)fluoren-9-one (2FF) and ionic liquid (IL) (2FF/$Cu-TiO_2$/IL/CPE) was fabricated and employed to study the electrocatalytic oxidation of droxidopa, using cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV) as diagnostic techniques. It has been found that the oxidation of droxidopa at the surface of modified electrode occurs at a potential of about 295 mV less positive than that of an unmodified CPE. DPV exhibits a linear dynamic range from $5.0{\times}10^{-8}$ to $4.0{\times}10^{-4}M$ and a detection limit of 30.0 nM for droxidopa. Finally this modified electrode was used for simultaneous determination of droxidopa and tryptophan. Also the 2FF/$Cu-TiO_2$/IL/CPE shows excellent ability to determination of droxidopa and tryptophan in real samples.

Fabrication of Stretchable Transparent Electrodes

  • Oh, Jong Sik;Yeom, Geun Young
    • Applied Science and Convergence Technology
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    • v.26 no.6
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    • pp.149-156
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    • 2017
  • Recently, stretchable and transparent electrodes have received great attention owing to their potential for realizing wearable electronics. Unlike the traditional transparent electrodes represented by indium tin oxide (ITO), stretchable and transparent electrodes are able to maintain their electrical and mechanical properties even under stretching stress. Lots of research efforts have been dedicated to the development of stretchable and transparent electrodes since they represent the most important engineering platform for the production of wearable electronics. Various approaches using silver nanowires, nanostructured networks, conductive polymers, and carbon-based electrodes have been explored by many world leading research groups. In this review, present and recent advances in the fabrication methods of stretchable and transparent electrodes are discussed.

Ultrahigh supercapacitance in cobalt oxide nanorod film grown by oblique angle deposition technique

  • Kannan, V.;Choi, Jong-Hyeok;Park, Hyun-Chang;Kim, Hyun-Seok
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1399-1402
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    • 2018
  • Nanorod films of cobalt oxide ($Co_3O_4$) have been grown by a unique oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor electrode applications. This technique offers a non-chemical route to achieve large aspect ratio nanorods. The fabricated electrodes at OAD $80^{\circ}$ exhibited a specific capacitance of 2875 F/g. The electrochemically active surface area was $1397cm^{-2}$, estimated from the non-Faradaic capacitive current region. Peak energy and power densities obtained for $Co_3O_4$ nanorods were 57.7 Wh/Kg and 9.5 kW/kg, respectively. The $Co_3O_4$ nanorod electrode showed a good endurance of 2000 charge-discharge cycles with 62% retention. The OAD approach for fabricating supercapacitor nanostructured electrodes can be exploited for the fabrication of a broad range of metal oxide materials.

Pore Gradient Nickel-Copper Nanostructured Foam Electrode (기공 경사화된 나노 구조의 니켈-구리 거품 전극)

  • Choi, Woo-Sung;Shin, Heon-Cheol
    • Journal of the Korean Electrochemical Society
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    • v.13 no.4
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    • pp.270-276
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    • 2010
  • Nickel-copper foam electrodes with pore gradient micro framework and nano-ramified wall have been prepared by using an electrochemical deposition process. Growth habit of nickel-copper co-deposits was quite different from that of pure nickel deposit. In particular, the ramified structure of the individual particles was getting clear with chloride ion content in the electrolyte. The ratio of nickel to copper in the deposits decreased with the distance away from the substrate and the more chloride ions in the electrolyte led to the more nickel content throughout the deposits. Compositional analysis for the cross section of a ramified branch, together with tactical selective copper etching, proved that the copper content increased with approaching central region of the cross section. Such a composition gradient actually disappeared after heat treatment. It is anticipated that the pore gradient nickel-copper nanostructured foams presented in this work might be a promising option for the high-performance electrode in functional electrochemical devices.

Concurrent Electrocatalysis and Sensing of Hydrazine and Sulfite and Nitrite Ions using Electrodeposited Gold Nanostructure-Modified Electrode

  • Seo, Yeji;Manivannan, Shanmugam;Kang, Inhak;Shin, Woo-Seung;Kim, Kyuwon
    • Journal of Electrochemical Science and Technology
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    • v.8 no.1
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    • pp.25-34
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    • 2017
  • Concurrent electrocatalysis and sensing of hydrazine, sulfite ions, and nitrite ions in a mixture were studied using electrodes modified by electrodeposited Au nanostructures (NSs). The ${\beta}$-cyclodextrin-mixed silicate sol-gel composite was drop-casted on the electrode surface and nucleation guided by ${\beta}$-cyclodextrin occurred, followed by the electrodeposition of Au NSs. The additive, ${\beta}$-cyclodextrin, played an evident role as a structure-directing agent; thus, small raspberry-like Au NSs were obtained. The modified electrodes were characterized by surface characterization techniques and electrochemical methods. The Au NSs-modified electrodes effciently electrocatalyzed the oxidation of toxic molecules such as hydrazine and sulfite and nitrite ions even in the absence of any other electron transfer mediator or enzyme immobilization. Well-resolved oxidation peaks along with decreased overpotentials were noticed during the electrooxidation process. The fabricated Au nanostructured electrode clearly distinguished the electrooxidation peaks of each of the three analytes from their mixture.

Influence of Nanostructured TiO2 Electrode Fabricated with Acid-treated Paste on the Photovoltaic Efficiency of Dye-Sensitized Solar Cells (산처리된 페이스트로 제조한 나노 구조체 TiO2 전극이 염료감응형 태양전지의 효율에 미치는 영향)

  • Lee, Jae-Wook;Hwang, Kyung-Jun;Roh, Sung-Hee;Kim, Sun-Il
    • Applied Chemistry for Engineering
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    • v.18 no.4
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    • pp.356-360
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    • 2007
  • Recently, dye sensitized solar cells (DSSCs) composed of nanoporous $TiO_2$, light-sensitive dyes, electrolytes, and counter electrode have been received much attention. Nanostructured particles with higher surface area for the higher adsorption of Ru (II) dye are required to increase the quantity of light absorption. Also, it has been reported that the key factor to achieve high energy conversion efficiency in the photoelectrode of DSSC is the heat treatment of $TiO_2$ paste with acid addition. In this work, we investigated the influence of acid treatment of $TiO_2$ solar cell on the photovoltaic performance of DSSC. The working electrodes fabricated in this work were characterized by X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), field emission scanning electron microscope (FE-SEM), and atomic force microscope (AFM). In addition, the influence of nanostructured photoelectrode fabricated with the acid-treated paste on the energy conversion efficiency was investigated on the basis of photocurrent-potential curves. It was found that the influence of acid-treated paste on the photovoltaic efficiency was significant.