• 제목/요약/키워드: electrochemical synthesis

검색결과 542건 처리시간 0.02초

Electrochemical Properties of Polyaniline Electrodes Prepared by Chemical Synthesis and Electrodeposition: Revisited with High-Scan-Rate Behaviors

  • Nam, Ji Hyun;Woo, Cho Hyeon;Kim, Kwang Man;Ryu, Kwang Sun;Ko, Jang Myoun
    • Journal of Electrochemical Science and Technology
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    • 제3권2호
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    • pp.80-84
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    • 2012
  • The polyaniline (PANI) electrodes are prepared by chemical synthesis and electrodeposition methods and their supercapacitive properties are characterized and compared by morphology observation, cyclic voltammetry as a function of scan rate, and impedance spectra analysis. In particular, the supercapacitive properties obtained in the range of higher potential scan rates (e.g., over $200mV\;s^{-1}$) are emphasized to be capable of utilizing adequately the high power capability of supercapacitor. As a result, the PANI electrode by the electrodeposition shows superior specific capacitance (max. $474F\;g^{-1}$ at $10mV\;s^{-1}$ and about $390F\;g^{-1}$ at $500mV\;s^{-1}$) than those by the chemical synthesis method. This is mainly due to highly porous structure obtained by the electrodeposition to yield higher specific surface area.

Electrochemical synthesis of nanosized hydroxyapatite/graphene composite powder

  • Vesna, Miskovic-Stankovic;Sanja, Erakovic;Ana, Jankovic;Maja, Vukasinovic-Sekulic;Miodrag, Mitric;Jung, Young Chan;Park, Soo Jin;Rhee, Kyong Yop
    • Carbon letters
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    • 제16권4호
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    • pp.233-240
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    • 2015
  • Electrochemical synthesis was employed to prepare a novel hydroxyapatite/graphene (HAP/Gr) composite powder suitable for medical applications as a hard tissue implant (scaffold). The synthesis was performed in a homogeneous dispersion containing Na2H2EDTA·2H2O, NaH2PO4 and CaCl2 with a Ca/EDTA/PO43− concentration ratio of 0.25/0.25/0.15M, along with 0.01 wt% added graphene nanosheets, at a current density of 137 mA cm−2 and pH value of 9.0. The field emission scanning electron microscopy and transmission electron microscopy observations of the composite HAP/Gr powder indicated that nanosized hydroxyapatite particles were uniformly placed in the graphene overlay. Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction confirmed graphene incorporation in the HAP/Gr powder. The electrochemically prepared HAP/Gr composite powder exhibited slight antibacterial effect against the growth of the bacterial strain Staphylococcus aureus.

Effect of Particle Size and Doping on the Electrochemical Characteristics of Ca-doped LiCoO2 Cathodes

  • Hasan, Fuead;Kim, Jinhong;Song, Heewon;Lee, Seon Hwa;Sung, Jong Hun;Kim, Jisu;Yoo, Hyun Deog
    • Journal of Electrochemical Science and Technology
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    • 제11권4호
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    • pp.352-360
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    • 2020
  • Lithium cobalt oxide (LiCoO2, LCO) has been widely used as a cathode material for Li-ion batteries (LIBs) owing to its excellent electrochemical performance and highly reproducible synthesis even with mass production. To improve the energy density of the LIBs for their deployment in electro-mobility, the full capacity and voltage of the cathode materials need to exploited, especially by operating them at a higher voltage. Herein, we doped LCO with divalent calcium-ion (Ca2+) to stabilize its layered structure during the batteries' operation. The Ca-doped LCO was synthesized by two different routes, namely solid-state and co-precipitation methods, which led to different average particle sizes and levels of dopant's homogeneity. Of these two, the solid-state synthesis resulted in smaller particles with a better homogeneity of the dopant, which led to better electrochemical performance, specifically when operated at a high voltage of 4.5 V. Electrochemical simulations based on a single particle model provided theoretical corroboration for the positive effects of the reduced particle size on the higher rate capability.

Sustainable Development of Palm Oil: Synthesis and Electrochemical Performance of Corrosion Inhibitors

  • Porcayo-Calderon, J.;Rivera-Munoz, E.M.;Peza-Ledesma, C.;Casales-Diaz, M.;de la Escalera, L.M. Martinez;Canto, J.;Martinez-Gomez, L.
    • Journal of Electrochemical Science and Technology
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    • 제8권2호
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    • pp.133-145
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    • 2017
  • Palm oil production is among the highest worldwide, and it has been mainly used in the food industry and other commodities. Currently, a lot of palm oil production has been destined for the synthesis of biodiesel; however, its use in applications other than the food industry has been questioned. Thereby for a sustainable development, in this paper the use of palm oil of low quality for corrosion inhibitors synthesis is proposed. The performance of the synthesized inhibitors was evaluated by using electrochemical techniques such as open circuit potential measurements, linear polarization resistance and electrochemical impedance spectroscopy. The results indicate that the fatty amides from palm oil are excellent corrosion inhibitors with protection efficiencies greater than 98%. Fatty amides molecules act as cathodic inhibitors decreasing the anodic dissolution of iron. When fatty amides are added, a rapid decrease in the corrosion rate occurs due to the rapid formation of a molecular film onto carbon steel surface. During the adsorption process of the inhibitor a self-organization of the hydrocarbon chains takes place forming a tightly packed hydrophobic film. These results demonstrate that the use of palm oil for the production of green inhibitors promises to be an excellent alternative for a sustainable use of the palm oil production.

Synthesis and Characterisation of Mixed Conducting Perovskite Type Oxide and Its Electrochemical Application to Electrode Material for Solid Oxide Fuel Cell

  • Kim, Yu-Mi;Pyun, Su-Il;Lee, Gyoung-Ja;Kim, Ju-Sik
    • 전기화학회지
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    • 제10권2호
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    • pp.116-125
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    • 2007
  • This article is concerned with synthesis, characterisation and electrochemical application of the mixed conducting perovskite type oxide to electrode materials for solid oxide fuel cell. First, this review provides a comprehensive survey of the various synthetic methods such as solid state reaction, Pechini, glycine nitrate process and sol-gel methods for the preparation of perovskite type oxide powders. Subsequently, the electrical and microstructural properties of the mixed conducting oxides were discussed in detail. Finally, as electrochemical applications of the mixed conducting perovskite type oxides to electrode materials for solid oxide fuel cell, fundamentals of theoretical ac-impedance model for porous mixed conducting electrodes were introduced. Furthermore, the ac-impedance behaviour of porous and dense mixed conducting electrodes prepared by various synthetic methods was discussed.

Template Synthesis of Nitrogen-Doped Short Tubular Carbons with Big Inner Diameter and their Application in Electrochemical Sensing

  • Cheng, Rui;Zou, Qiong;Zhang, Xiaohua;Xiao, Chunhui;Sun, Longfei;Chen, Jinhua
    • Bulletin of the Korean Chemical Society
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    • 제35권8호
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    • pp.2423-2430
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    • 2014
  • Nitrogen-doped short tubular carbons (N-STCs) with big inner diameter have been successfully synthesized via carbonization of polydopamine (PDA) wrapped halloysite nanotubes (HNTs). The obtained N-STCs have average length of $0.3{\mu}m$ with big inner diameter (50 nm), thin wall (2-3 nm) and large surface area ($776m^2g^{-1}$), and show excellent electrochemical properties. As an example in electrochemical applications, N-STCs were used to electrochemically detect hydrogen peroxide ($H_2O_2$) and glucose. The results showed that the N-STCs modified glassy carbon (N-STCs/GC) electrode had much better analytical performance (lower detection limit and wider linear range) compared to the acid-treated carbon nanotubes (AO-CNTs) based GC electrode. The unique structure endows N-STCs the enhanced electrochemical performance and promising applications in electrochemical sensing.