• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1090-1094
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• 2004

Studies on porous oxide electrode, dye and electrolyte for dye-sensitized solar cells have been intensively carried out until now. However, counter electrode have not been much studied so far. Accordingly, it is needed to investigate new counter electrode materials with superior catalyst property and to substitute for Pt electrode. In this case, carbon nano-tubes (CNTs) are one of alternatives for counter electrodes as following merits: low resistivity, excellent electron emission property, large surface area and low cost due to development of mass production technique. Such advantages gave us to select multiwalled CNTs (MWCNT) as counter electrode for dye-sensitized solar cell. Also, cyclic voltammetry and impedance spectroscopy were used to investigate electrochemical properties of both CNT electrode and Pt electrode. It was found that sheet resistance of CNT electrode was similar to that of Pt electrode, also, electrochemical properties of CNT electrode was superior to that of Pt electrode on the basis on the measurement of CV and impedance spectrum. It was found that CNT is likely to be a very promising electrode material for dye solar cells.

• Journal of Electrochemical Science and Technology
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• v.5 no.1
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• pp.1-18
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• 2014

Li-air cell is an exotic type of energy storage and conversion device considered to be half battery and half fuel cell. Its successful commercialization highly depends on the timely development of key components. Among these key components, the catalyst (i.e., the core portion of the air electrode) is of critical importance and of the upmost priority. Indeed, it is expected that these catalysts will have a direct and dramatic impact on the Li-air cell's performance by reducing overpotentials, as well as by enhancing the overall capacity and cycle life of Li-air cells. Unfortunately, the technological advancement related to catalysts is sluggish at present. Based on the insights gained from this review, this sluggishness is due to challenges in both the commercialization of the catalyst, and the fundamental studies pertaining to its development. Challenges in the commercialization of the catalyst can be summarized as 1) the identification of superior materials for Li-air cell catalysts, 2) the development of fundamental, material-based assessments for potential catalyst materials, 3) the achievement of a reduction in both cost and time concerning the design of the Li-air cell catalysts. As for the challenges concerning the fundamental studies of Li-air cell catalysts, they are 1) the development of experimental techniques for determining both the nano and micro structure of catalysts, 2) the attainment of both repeatable and verifiable experimental characteristics of catalyst degradation, 3) the development of the predictive capability pertaining to the performance of the catalyst using fundamental material properties. Therefore, under the current circumstances, it is going to be an extremely daunting task to develop appropriate catalysts for the commercialization of Li-air batteries; at least within the foreseeable future. Regardless, nano materials are expected to play a crucial role in this field.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.188-190
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• 2007

The MEA with the catalyst layer containing PtRu black and 60 wt. %Pt/C as their anode and cathode catalysts. For find to effect of carbon support, the MEA with platinum black for cathode catalyst was fabricated. The performance of the MEA with the catalyst layer containing (PtRu black:60 wt.% Pt/C) as their anode and cathode catalyst has shown competitively higher value than the performance of the MEA with the catalyst layer containing (PtRu black:Pt black) as their anode and cathode catalyst.

• Journal of the Korean institute of surface engineering
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• v.52 no.3
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• pp.150-155
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• 2019

The carbon electrode was modified through manganese-catalyzed hydrogenation method for high energy density vanadium redox flow battery (VRFB). During the catalytic hydrogenation, the manganese oxide deposited at the surface of the carbon electrode stimulated the conversion reaction from carbon to methane gas. This reaction causes the penetration of the manganese and excavates a number of cavities at electrode surface, which increases the electrochemical activity by inducing additional electrochemically active site. The formation of the porous surface was confirmed by the scanning electron microscopy (SEM) images. Finally, the electrochemical performance test of the electrode with the porous surface showed lower polarization and high reversibility in the cathodic reaction compared to the conventional electrode.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.202-207
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• 2022

The study on electrode degradation of Proton Exchange Membrane Fuel Cell (PEMFC) was mainly studied on the particle growth and active area reduction of Pt on the electrode. The degradation of the electrode catalyst Pt in contact with the membrane affects the deterioration of the polymer membrane, but there are not many studies related to this. In this study, the phenomenon of the deposition of deteriorated Pt inside the polymer membrane during the accelerated electrode catalyst degradation test and its effects were studied. The voltage change (0.6 V ↔ 0.9 V) was repeated up to 30,000 cycles to accelerate the platinum degradation rate. When the voltage change cycle was repeated while oxygen was introduced into the cathode, the amount of Pt deposited inside the film was larger than when nitrogen was introduced. As the number of voltage change cycles increased, the amount of Pt deposited inside the membrane increased, and Pt dissolved in the cathode moved toward the anode, showing a uniform distribution throughout the membrane at 20,000 cycles. In the process of the accelerated electrode catalyst degradation test, the hydrogen crossover current density of the membrane did not change, and it was confirmed that the deposited Pt did not affect the durability of the membrane.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.84.1-84.1
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• 2010

Since the discovery of the carbon nanotube(CNTs), they have attracted much attention because of unique properties that may impact many fields of science and technology. The considerable properties of CNTs include high surface area, outstanding thermal, electrical conductivity and mechanical stability. However, uniform deposition of Pt nanoparticles on carbon surface remains inaccessible territory because of the inert carbon surface. In this study, we prepared directly oriented CNTs on carbon paper as a catalyst support in cathode electrode. carbon surface was functionalized using aryl diazonium salt for increasing adhesion of Ni particles which is precursor for growing CNTs. For fabricate electrode, CNTs on carbon paper were grown by chemical vapor deposition using Ni catalyst and Pt nanoparticles were deposited on CNTs oriented carbon paper by polyol method. The performance was measured using Proton electrolyte Membrane Fuel Cell(PEMFC). The structure and morphology of the Pt nanoparticles on CNTs were characterized by Scanning electron Microscopy(SEM) and Transmission electron Microscopy (TEM). The average diameter of Pt nanoparticles was 3nm.

• Korean Journal of Materials Research
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• v.28 no.1
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• pp.50-61
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• 2018

Various carbon aerogels (CAs) were prepared from polymerization of resorcinol and formaldehyde and applied as the electrode materials of an electric double layer capacitor (EDLC) with the aim of controlling the textural and electrochemical properties of CAs by the type of base catalyst and the ratio of resorcinol to catalyst (R/C). The CAs from $NaHCO_3$ and $KHCO_3$ with $H^+$ ions had higher specific surface areas but exhibited lower electrochemical properties than those from $K_2CO_3$ and $Na_2CO_3$, which had more uniform pore size distributions. The electrochemical properties of $Na_2CO_3$ were superior to those of $K_2CO_3$ probably because the polarizing power of $Na^+$ ions was higher than $K^+$ ions. With an increasing R/C ratio, the pore sizes of CA showed a tendency to increase but the uniformity of the pore size distribution got worse. For the four base catalysts, the highest electrochemical property was obtained at the R/C ratio of 500.

• Journal of the Korean Electrochemical Society
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• v.7 no.4
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• pp.201-205
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• 2004

The Pt-Ru electrocatalyst was Prepared on Nafion membrane modified with Polypyrrole by chemical reduction of $H_2PtCI_6\;and\;RuCl_3$ solution ai precursor. From the electron dispersive microanalysis spectroscope(EDS), the Pt-Ru catalyst was located on the surface of Ppy/Nafion composite. The electrochemical oxidation of methanol on Pt-Ru catalyst deposited in Polypyrrole-impregnated Nafion was investigated by cyclic voltammetry (CV) and chronoamperometry. The onset potential of methanol oxidation was shifted to negative potential as the $RuCI_3$ concentration in deposition solution. Also, it was known that the Pt-Ru binary catalyst on Nafion could be directly deposited by using Polypyrrole and resulting Pt-Ru/PPy/Nafion was available for methanol oxidation.

• Korean Journal of Materials Research
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• v.21 no.3
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• pp.138-143
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• 2011

Nanosized Pt, Pt-Ru and Pt-$CeO_2$ electrocatalysts supported on acid-treated carbon nanotube (CNT) were synthesized by microwave-assisted heating of polyol process using $H_2Cl_6Pt{\cdot}6H_2O$, $RuCl_3$, $CeCl_3$ precursors, respectively, and were characterized by XRD and TEM. And then the electrochemical activity of methanol oxidation for catalyst/CNT nanocomposite electrodes was investigated. The microwave assisted polyol process produced the nano-sized crystalline catalysts particles on CNT. The size of Pt supported on CNT was 7~12 nm but it decreased to 3~5 nm in which 10wt% sodium acetate was added as a stabilizer during the polyol process. This fine Pt catalyst particles resulted in a higher current density for Pt/CNT electrode. It was also found that 10 nm size of PtRu alloys were formed by polyol process and the onset potential decreased with Ru addition. Cyclic voltammetry analysis revealed that the $Pt_{75}Ru_{25}/CNT$ electrode had the highest electrochemical activity owing to a higher ratio of the forward to reverse anodic peak current. And the chronoamperemetry test showed that $Pt_{75}Ru_{25}$ catalyst had a good catalyst stability. The activity of Pt was also found to be improved with the addition of $CeO_2$.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.505-506
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• 2008

The direct methanol fuel cell (DMFC) is a promising power source for portable applications due to many advantages such as simple construction, compact design, high energy density, and relatively high energy-conversion efficiency. In this work, an electrochemical methanol sensor for monitoring the methanol concentration in direct methanol fuel cells was fabricated using a thin composite nafion membrane as the electrolyte. We have analyzed the I-V characteristic of the fabricated methanol sensor as a function of methanol concentration, catalyst electrode and platinum(Pt) dot.