• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.695-700
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• 2014

Proton Exchange Membrane Fuel Cells (PEMFC) can generate hydrogen and oxygen from water by electrolysis. But the electrode and polymer electrolyte membrane degrade rapidly during PEM water electrolysis because of high operation voltage over 1.7V. In order to reduce the rate of anode electrode degradation, unsupported $IrO_2$ catalyst was used generally. In this study, Pt/C catalyst for PEMFC was used as a water electrolysis catalyst, and then the degradation of catalyst and membrane were analysed. After water electrolysis reaction in the voltage range from 1.8V to 2.0V, I-V curves, impedance spectra, cyclic voltammograms and linear sweep voltammetry (LSV) were measured at PEMFC operation condition. The degradation rate of electrode and membrane increased as the voltage of water electrolysis increased. The hydrogen yield was 88 % during water electrolysis for 1 min at 2.0V, the performance at 0.6V decreased to 49% due to degradation of membrane and electrode assembly.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.33-37
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• 2023

Efforts by each country to solve the climate change problem continue, and the transition to eco-friendly fuels is a task for mankind to continue. Recently, Jeju Island, where renewable energy resources are relatively abundant, is preparing to demonstrate the technology to produce green hydrogen linked to renewable energy and this study aims to introduce and apply polymer electrolyte water electrolysis devices of advanced foreign companies after comparing domestic and foreign technologies. This study aims to solve domestic safety regulations for water electrolysis devices manufactured overseas and system introduction process and evaluation method of core components.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.341-348
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• 2016

The experiments related on structure and water electrolysis performance of HALE UAV stack were conducted in this study. Anode catalyst $IrRuO_2$ was prepared by Adam's fusion methods as 2~3 nm nano sized particles, and the cathode catalyst was used as commercial product of Premetek. The MEA (membrane electrode assembly) was manufactured by decal methods, anode and anode catalytic layers were prepared by electro-spray. HALE stack was composed of 5 multi-cells as $0.2Nm^3/hr$ hydrogen production rate with hydrogen pressure as 10 bar. The water electrolysis performance was investigated at atmospheric pressure and temperature of $55^{\circ}C$. Best performance of HALE UAV stack was recorded as cell voltage efficiency as 86%.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.13-21
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• 2016

In this paper we are trying to explain the effect of temperature on polymer membrane exchange water electrolysis (PEMWE) and polymer membrane exchange fuel cell (PEMFC) simultaneously. A comprehensive studying approach is proposed and applied to a 50Watt PEM fuel cell system in the laboratory. The monitoring process is carried out through wireless LoRa node and gateway network concept. In this experiment, temperature sensor measure the temperature level of electrolyzer, fuel cell stack and $H_2$ storage tank and transmitted the measured value of data to the management control unit (MCU) through the individual node and gateway of each PEMWE and PEMFC. In MCU we can monitor the temperature and its effect on the performance of the fuel cell system and control it to keep the lower heating value to increase the efficiency of the fuel cell system. And we also proposed a mathematical model and operation algorithm for PEMWE and PEMFC. In this model, PEMWE gives higher efficiency at lower heating level where as PEMFC gives higher efficiency at higher heating value. In order to increase the performance of the fuel cell system, we are going to monitor, communicate and control the temperature and pressure of PEMWE and PEMFC by installing these systems in a building of university which is located in the southern part of Korea.

• Journal of the Korean Electrochemical Society
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• v.25 no.2
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• pp.69-80
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• 2022

The anion exchange membrane (AEM) water electrolysis for high purity hydrogen production is attracting attention as a next-generation green hydrogen production technology by using inexpensive non-noble metal-based catalysts instead of conventional precious metal catalysts used in proton exchange membrane (PEM) water electrolysis systems. However, since AEM water electrolysis technology is in the early stages of development, it is necessary to develop research on AEM, ionomers, electrode supports and catalysts, which are key elements of AEM water electrolysis. Among them, current research in the field of catalysts is being studied to apply a previously developed half-cell catalyst for alkali to the AEM system, and the applied catalyst has disadvantages of low activity and durability. Therefore, this review presented a catalyst synthesis technique that promoted oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) using a non-noble metal-based catalyst in an alkaline medium.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.4
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• pp.288-294
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• 2013

This gas analysis data come from the hydrogen which is produced by proton exchange membrane. Main impurities of hydrogen are methane, oxygen, nitrogen, carbon monoxide, and carbon dioxide. The concentration of impurities is ranged between 0.0191 to $315{\mu}mol/mol$ for each impurity. Methane contamination is believed from the electrode reaction between carbon doped electrode and produced hydrogen. Nitrogen contamination should take place the sampling process error, not from PEM hydrogen Production system.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.5-11
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• 2022

Despite the increasing importance of manufacturing and application R&D for ultrapure deionized water and electrolyzed ion water, various and systematic studies have not been conducted until now. In this study, the electrostatic discharge (ESD) behavior of electrolyzed ion water using a proton exchange membrane(PEM) was evaluated according to the type, flow rate, and bubble of electrolyzed ion water. In addition, by observing that Oxidation Reduction Potential (ORP) value returns to the unique value of electrolyzed ion water after electrostatic discharge, the possibility of two types of ions participating in electrostatic discharge ((H₂O)_n⁺ (assumed)) and ions for maintaining the characteristics of electrolyzed water could be inferred. In order to confirm the chemical structure and characteristics of the cations, in-depth research related to water molecular orbital energy or band gap should be followed.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.338-344
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• 2017

Polyoxometal molybdophosphoric acid (MoPA) bonded polyether ether ketone (PEEK) composite membrane for water electrolysis has been investigated. The composited membrane, covalently cross linked (CL) sulfonated polyether ether ketone (SPEEK) with a bonded MoPA, was prepared in sulfonation of PEEK, cross linkage reaction with 1,4-diiodobutane, and addition with MoPA. PEEK was covalently cross-linked with 1,4-diiodobutane to improve mechanical strength and was added with MoPA to increase proton conductivity. MoPA should be fixed to back bone of SPEEK to prevent bleeding out. Therefore, the carbonyl group of SPEEK was reduced with NaBH4 and 3-isocyanatepropyltriethoxysilane (ICPTES) was added. The MoPA bonded composite was produced in the reaction of MoPA with 3-mercaptopropyltrimethoxvsilane (MPTMS). In conclusion, MoPA bonded CL-SPEEK composite membrane featured 0.129 S/cm of proton conductivity at $80^{\circ}C$, and 2,156 hours of chemical stability in Fenton test. These properties are better than those of membranes of other SPEEK system.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.471-477
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• 2016

In this research, the Ir supported $TiO_2$ (P25) catalyst was prepared by precipitation method for oxygen evolution reaction. The $Ir/TiO_2$ catalyst was synthesised by reduction reaction using reducing agent. Physiochemical characterizations of synthesized $Ir/TiO_2$ catalyst was studied by means of SEM, EDS mapping, TEM and XRD. The Electrochemical characterizations were tested by using the technique of CV and LSV by RDE and Potentiostat. Physicochemical properties were characterized with XRD where Iridium metal morphology and Ir(111) and Ir(222) peaks were founded. $Ir0.2Ru0.8O_2$ exhibited higher OER activity than $Ir0.5Ru0.5O_2$ followed by $Ir/TiO_2$ and $IrO_2$.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.3
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• pp.194-201
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• 2009

The e1ectrocatalytic properties of heteropolyacids(HPAs) entrapped in covalently cross-linked sulfonated polyetheretherketone(CL-SPEEK/HPA) membranes have been studied for water electrolysis. The HPAs, including tungstophosphoric acid(TPA), molybdophosphoric acid(MoPA), and tungstosilicic acid(TSiA) were used as additives in the composite membranes. The MEA was prepared by a non-equilibrium impregnation-reduction(I-R) method, using reducing agent, sodium borohydride(NaBH4) and tetraamineplatinum(II) chloride(pt(NH$_3$)$_4$Cl$_2$). The electrocatalytic properties of composite membranes such as the cell voltage were in the order of magnitude CL-SPEEKlMoPA40 (wt%) > /TPA30 > /TSiA40. In the optimum cell applications for water electrolysis, the cell voltage of PtlPEM/Pt-Ru MEA with CL-SPEEKlTPA30 membrane was 1.75 V at 80$^{\circ}$C and I A/cm$^2$ and this voltage carried lower than that of 1.81 V of Nafion 117. Consequently, in regards of electrochemical and mechanical characteristics and oxidation durability, the newly developed CL-SPEEKITPA30 composite membrane exhibited a better performance than the others, but CLSPEEKlMoPA40 showed the best electrocatalytic activity (1.71 Vat 80$^{\circ}$C and 1 A/cm$^2$) among the composite membranes.