• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.158-160
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• 2003

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400 F/g (specific capacitance) and good cycleability. But, it had serious demerits of low voltage range under 0.5 V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. We report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over 250 F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100 F/g capacitance. This capacitance was only electric double layer capacitance of active surface area. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Itis very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.237-237
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• 2007

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2541-2543
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• 2014

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.12-27
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• 2018

Supercapacitors (SCs) has gained an impressive concentration by the researchers due to its advantages such as high energy and power densities, long cyclic life, rapid charge-discharge rates, low maintenance and desirable safety. Hence it has been widely utilized in energy storage and conversion devices. Among the different components of SC, electrodes play a vital role in the performances of SCs. In this review, we present the recent advances in 2-D nanostructured metal nitrides, carbides, and phosphides based materials for SC electrodes. Finally, the electrochemical stability and designing approach for the future advancement of the electrode materials are also highlighted.

• Journal of the Korean Ceramic Society
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• v.56 no.5
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• pp.497-505
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• 2019

Lanthanum-based transition metal cations containing perovskites have emerged as potential catalysts for the intermediate-temperature (600-800℃) oxygen reduction reaction (ORR). Here, we report a facile acetylacetone-assisted combustion route for the synthesis of nanostructured La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF6428) cathodes for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). The as-prepared powder was analyzed by thermogravimetry analysis-differential scanning calorimetry. The powder calcined at 800℃ was characterized by X-ray diffraction, scanning electrode microscopy, energy dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller surface area measurements. It was found that the porosity of the air electrode significantly increased by utilizing the nanostructured LSCF6428 instead of commercial powder. The performance of a single cell fabricated with the nanostructured LSCF6428 cathode increased by 112%, from 0.4 to 0.85 W cm^-2, at 700℃. Electrochemical impedance spectroscopy showed a considerable reduction in the area-specific resistance and activation energy from 133.5 to 61.5 kJ/mol, resulting in enhanced electrocatalytic activity toward ORR and overall cell performance.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.235-240
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• 2010

We investigated the carbon monoxide (CO) gas-sensing properties of nanostructured Al-doped zinc oxide thin films deposited on self-assembled Au nanodots (ZnO/Au thin films). The Al-doped ZnO thin film was deposited onto the structure by rf sputtering, resulting in a gas-sensing element comprising a ZnO-based active layer with an embedded Pt/Ti electrode covered by the self-assembled Au nanodots. Prior to the growth of the active ZnO layer, the Au nanodots were formed via annealing a thin Au layer with a thickness of 2 nm at a moderate temperature of $500^{\circ}C$. It was found that the ZnO/Au nanostructured thin film gas sensors showed a high maximum sensitivity to CO gas at $250^{\circ}C$ and a low CO detection limit of 5 ppm in dry air. Furthermore, the ZnO/Au thin film CO gas sensors exhibited fast response and recovery behaviors. The observed excellent CO gas-sensing properties of the nanostructured ZnO/Au thin films can be ascribed to the Au nanodots, acting as both a nucleation layer for the formation of the ZnO nanostructure and a catalyst in the CO surface reaction. These results suggest that the ZnO thin films deposited on self-assembled Au nanodots are promising for practical high-performance CO gas sensors.

• Journal of the Korean Electrochemical Society
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• v.18 no.3
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• pp.107-114
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• 2015

Electrochemical fabrication of nanostructured Au surfaces has received increased attention. In the present work, electrochemical modification of Au surfaces for fabricating nanostructured Au surfaces in the absence of externally added precursors is presented, which is different to the previous methods utilizing electrochemical deposition of externally added precursors. Application of anodic potential at Au surfaces in phosphate buffers containing $Br^-$ resulted in the anodic dissolution of Au, which produced Au precursors at the electrode surfaces. The resulting Au precursors were further reduced at the surface to produce nanostructured Au structures. The effects of applied potential and time on the morphology of Au nanostructures were systematically examined, from which a unique backbone type Au nanostructures was produced. The backbone type Au nanostructures exhibited high surface-enhanced Raman activity. The present work would give insights into the formation of electrochemical fabrication of nanostructured Au surfaces.

• Advances in nano research
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• v.1 no.2
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• pp.111-124
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• 2013

Surface-enhanced Raman scattering (SERS) effect deals with the enhancement of the Raman scattering intensity by molecules in the presence of a nanostructured metallic surface. The first observation of surface-enhanced Raman spectra was in 1974, when Fleischmann and his group at the University of Southampton, reported the first high-quality Raman spectra of monolayer-adsorbed pyridine on an electrochemically roughened Ag electrode surface. Over the last thirty years, it has developed into a versatile spectroscopic and analytical technique due to the rapid and explosive progress of nanoscience and nanotechnology. This review article describes the recent development in field of surface-enhanced Raman scattering research, especially fabrication of various SERS active substrates, mechanism of SERS effect and its various applications in both surface sciences and analytical sciences.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.10-18
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• 2010

Nanostructured metal oxides have been widely used in the research fields of photoelectrochemistry, photochemistry and opto-electronics. Dye-sensitized solar cell is a typical example because it is based on nanostructured $TiO_2$. Since the discovery of dye-sensitized solar cell in 1991, it has been considered as a promising photovoltaic solar cell because of low-cost, colorful and semitransparent characteristics. Unlike p-n junction type solar cell, dye-sensitized solar cell is photoelectrochemical type and is usually composed of the dye-adsorbed nanocrystalline metal oxide, the iodide/tri-iodide redox electrolyte and the Pt and/or carbon counter electrode. Among the studied issues to improve efficiency of dye-sensitized solar cell, nanoengineering technologies of metal oxide particle and film have been reviewed in terms of improving optical property, electron transport and electron life time.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.181.1-181.1
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• 2014

Supercapacitor is attracting growing attention for a promising energy conversion and storage device because of its desirable electrochemical properties such as rapid charge-discharge rate, high power density and long cycle life. Three-dimensional (3D) metal nanostructure has been widely studied since it can provide efficient charge transport along the 3D network in many device applications. In this work, we fabricated well-ordered 3D nickel (Ni) nanostructures using 3D-arrayed polystyrene nano-opal substrates. We also fabricated half-cell supercapacitors by electrodepositing $RuO_2$ onto these nanostructured Ni current collectors and investigated their morphological and electrochemical properties.