• 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.

• Journal of Sensor Science and Technology
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• v.29 no.4
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• pp.232-236
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• 2020

Three-dimensional (3D) multilayered Pt electrodes were fabricated to develop a porous electrode using a pattern-transfer printing process. The Pt thin films were deposited using a transferred sputtering pattern having a 250 nm line width on the substrate, and the uniform line patterns were efficiently transferred using our proposed method. Temperature-programmed desorption (TPD) analyses were used to evaluate the porosity of the electrodes. It was possible to distinguish between two resolved maxima at 168 and 227 ℃, which could be described in terms of desorption reactions on the Pt (111) planes. The results of the TPD analysis of the 3D and multilayered Pt electrodes prepared through transfer printing were compared to those of an electrode fabricated through screen printing using a commercial Pt-carbon paste commonly used as porous electrodes. It was confirmed that the 3D multilayered electrodes exhibited a desorption concentration approximately 100 times higher than that of the Pt-carbon composite electrode, and the desorption concentration increased by approximately 0.02 mg/mol per layer. The 3D multilayered electrode effectively functions as a porous electrode and a catalyst.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.35-43
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• 1998

Electrodes using for the anode electrode of direct methanol fuel cell with Pt/C and Pt/Ru/C catalyst were prepared and characterized by SEM, TEM, thermal analysis and electrochemical analysis. The half cell tests were carried out with 1 M $H_2SO_4$ electrolyte and 1 M $CH_3OH$ in order to evaluate the electrode performance. The employed electrochemical methods were cyclic vol-tammetry and potentiodynamic polarization experiments. It was found that 20 w% polytetrafluoroethylene (PTFE) content in catalyst showed the best performance due to the best platinum utilization on PTFE-containing catalyst layer. It was found that Pt/Ru/C binary catalyst inhibited the poisoning of anode electrode showing improved performance compared to the Pt/C catalyst by the adsorption of oxygen containing species on the electrode surface at same time. The apparent activation energy for methanol oxidation on the Pt/Ru/C and Pt/C catalyst layer was 11.60 kJ/mol and 26.85 kJ/mol, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.641-643
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• 2003

The ferroelectric properties of PZT(53/47) thin film was investigated by methoxy enthanol solution based on sol-gel method. The thickness of each layer by spincoating 0.25M sol at one time was $0.1{\mu}m$ and crack-free film was formed. $LaNiO_3/Si(100)$ electrode and $Pt/Ti/SiO_2/Si(100)$ electrode was coated by PZT sol at several times. PZT orientation was confirmed as a method of XRD and coercive field(Ec) as well as remnant polarization(Pr) was investigated from hysterisis curve. As a result of XRD analysis, we can know that the orientation of on PZT/LNO/Si(100) is better than on $Pt/Ti/SiO_2/Si(100)$. The remnant polarization(Pr) in LNO electrode was $87.5{\mu}C/cm^2$ and $39.8{\mu}C/cm^2$ in Pt. From this figures, it is investigated that the Pr in LNO electrode was better than in Pt.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.187-187
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• 2010

In this study, we investigated the effect of electrodes on resistance switching of TaOx film. Pt, Ni, TiN, Ti and Al metal electrodes having the different oxidation degree were deposited on TaOx/Pt stack. Unipolar resistance switching behavior in Pt or Ni/TaOx/Pt MIM stacks was investigated, but bipolar resistance switching behavior in TiN, Ti or Al /TaOx/Pt MIM stacks was shown. We investigated that the voltage dependence of capacitance was decreased with higher oxidation degree of metal electrodes. Through the C-V results, we expected that linearity ($\alpha$) and quadratic ($\beta$) coefficient was reduced with an increase of interface layer between top electrode and Tantalum oxide. Transmission Electron Microscope (TEM) images depicted the thickness of interface layer formed with different oxidation degree of top electrode. Unipolar resistance switching behavior shown in lower oxidation degree of top electrode was expected to be generated by the formation of the conducting path in TaOx film. But redox reaction in interface between top electrode and Tantalum oxide may play an important role on bipolar resistance switching behavior exhibited in higher oxidation degree of top electrode. We expected that the resistance switching characteristics were determined by oxidation degree of metal electrodes.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1992.11a
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• pp.39-40
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• 1992

This paper dealt with the manufacturing of binary alloy catalyst and showed simple electrochemical method for determing catalytic activity of oxygen reduction in acid or alkaline electrolyte. The catalyst was prepared by impregnating transition metal salts on platinum or silver particles adsorbed before on carbon paper substrate. The electrochemical characteristics of the catalysts was investigated with carbon paper electrode or PTFE-boned porous electrode and then cathodic current densities and tafel slopes were compared. As a result, of all binary catalysts utilized in this work, Pt-Fe, Pt-Mo showed better oxygen reduction activity than pure platinum catalyst in acid electrolyte and Ag-Fe, Ag-Pt, and Ag-Ni-Bi-Ti catalyst did than pure silver catalyst in alkaline electrolyte. The current density of Pt-Fe electrode in acid electrolyte was one and half times higher than that of Pt electrode(~500mA/$\textrm{cm}^2$ at 0.7VvsNHE).

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1126-1129
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• 2000

The crystallographic orientations of $Ba_{0.6}$S $r_{0.4}$Ti $O_3$(BST) thin film deposited by a metal-organic chemical vapor deposition on (111) textured Pt electrode were studied with a transmission electron microscopy. The fully crystallized BST thin film (50nm) has (100) and (110) preferred orientations. A high resolution transmission electron microscopy study has revealed the crystallographic orientation relationships between BST thin film and Pt electrode. These relationships explained the preferred orientation of BST film on (111) textured Pt electrode. With these results, we could represent the atomic arrangement at the BST/Pt interface.e.e.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.530-536
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• 2000

During the grain growth of the PZT thin films by selective nucleation method using PZT seed, it was found that the grain size was saturated with the annealing temperature. The saturation of grain size was analyzed by the interfacial energy which appeared during the crystallization. The factors affecting the saturation of grain size were found to be the interfacial energy between perovskite phase and pyrochlore phase, and PZT thin film and the bottom Pt electrode. When the ion damage was introduced to the grain-size saturated PZT thin films, further lateral growth was observed. Pt bottom electrode thickness was changed to control the interfacial energy between the PZT thin film and the Pt bottom electrode. When Pt thickness was increased, the grain size was also increased, because the lattice parameter of Pt films was increased with the thickness of the Pt films. The incubation time of nucleation was increased with the amount of the ion damage on the Pt films.

• 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.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.118.2-118.2
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• 2011

In order to increase the energy conversion efficiency of dye-sensitized solar cells (DSSCs), we employed a counter electrode that was platinum coated using a doctor blade technique on synthesized ZnO nanostructures on fluorinedoped tin oxide (FTO). The ZnO nanostructures possessing high electrochemical activity and large surface area of the counter electrode were grown by a chemical bath deposition (CBD) method at various times, 2, 4, and 8 h. The efficiency of DSSC with the Pt-ZnO counter electrode was improved 7.01% (grown for 2 h), 7.63% (grown for 4 h), and 6.13% (grown for 8 h), respectively. Compared with a standard DSSC without ZnO nanostructures, whose efficiency was 6.27%, the energy conversion efficiency increased approximately 22% for the DSSC with the Pt-ZnO (grown for 4 h) electrode. It indicates that the Pt coated on the ZnO nanostructure improves the electrocatalytic activity of the counter electrode.