• Journal of the Korean Electrochemical Society
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• v.23 no.3
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• pp.73-80
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• 2020

Fenton oxidation method using hydrogen peroxide is an eco-friendly oxidation method used in water treatment and soil restoration. When removing pollutants by this method, it is quite important to properly regulate the concentration of hydrogen peroxide according to the concentration of the contaminants. In this study, electrochemical biosensors using HRP (horseradish peroxidase) enzymes were manufactured and studies were conducted on the activity of enzymes and the detection characteristics of hydrogen peroxide. HRP were electro deposited with chitosan and AuNP on the working electrode surface of the SPCE (Screen Printed Carbon Electrode). Then, the fixation of enzymes was confirmed using the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The activity of HRP enzymes was also identified from chronoamperometry (CA) and UV spectroscopy. After immersing the biosensor in PBS solution the current generated from electrodes by titrating hydrogen peroxide was measured from CA analysis. The generated current increased linearly for the concentration of hydrogen peroxide, and a calibration curve was derived that could predict the concentration of hydrogen peroxide from the current.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.293-298
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• 2016

A hydrogel electrolyte consisting of 6 M KOH aqueous solution, potassium polyacrylate (PAAK, 3 wt.%), and a hydrophilic silica OX50 (1 wt.%) was prepared to use as an electrolyte medium coated on a Scimat separator of activated carbon supercapacitor. The silica particle distributed homogeneously on surface pores of the separator to increase ionic conductivity and electrochemical stability of the hydrogel electrolyte. The silica addition also involved superior specific capacitance even at higher scan rates due to decrease in interfacial resistance between hydrogel electrolyte and activated carbon electrode.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.157-162
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• 2014

In this research, we investigate electrical performance and electrochemical properties of carbon supported Pt (Pt/C) that is synthesized by polyol method. With the Polyol_Pt/C that is adopted for oxygen reduction reaction (ORR) as cathode of proton exchange membrane fuel cells (PEMFCs), their catalytic activity and ORR performance and electrical performance are estimated and compared with commercial Pt/C(Johnson Mattey) catalyst. Their electrochemically active surface (EAS) area are measured by cyclic voltammetry (CV), respectively. On the other hand, regarding ORR activity and electrical performance of the catalysts, (i) linear sweeping voltammetry by rotating disk electrode and (ii) PEMFC single cell tests are used. The CV measurement demonstrate EAS of Polyol_Pt/C is compared with commercial JM_Pt/C. In case of Polyol_Pt/C, its half-wave potential, kinetic current density are excellent. Based on data obtained by half-cell test, when PEMFC single cell tests are carried out, current density measured at 0.6V and maximum power density of the PEMFC single cell employing Polyol_Pt/C are better than those employing commercial Pt/C. Conclusively, Polyol_Pt/C synthesized by modified polyol process shows better ORR catalytic activity and PEMFC performance than other catalysts.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.727-731
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• 2008

Mesoporous Pt-Au alloy films were successfully fabricated on ITO-coated glass by electrodeposition method using tri-blockcopolymer (P123) as a templating agent. The electrolyte consisted of 10 mM hydrogen hexachloroplatinate ($H_2PtCl_6$), 10 mM hydrogen tetrachloroaurate ($HAuCl_4$), and proper amount of P123. For comparison, control samples were electrodeposited without $HAuCl_4$ and P123. Film composition was determined by EDS(Energy Dispersive X-ray Spectroscopy), and the mesoporous structure was confirmed by TEM(Transmission Electron Microscopy). SEM(Scanning Electron Microscopy) was utilized to examine surface morphology, and it was observed that the addition of P123 affected the particle growth, resulting in the significant change of surface morphology. Methanol oxidation and CO oxidation were carried out to investigate electrocatalytic activities of synthesized samples. It was observed that the catalytic activity was strongly dependent on the film compositions. Compared with nonporous electrode prepared without P123 templating, mesoporous films prepared with P123 templating showed much higher catalytic activities and stability for both methanol oxidation and CO oxidation. These enhanced electrocatalytic activities were due to the high surface area and facilitated charge transfer of mesoporous films.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.206-211
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• 2017

Carbon felt electrode for the vanadium redox-flow battery (VRFB) has been studied to see the effect of grephene oxide (GO) treatment on the surface of the carbon felt electrode. In this paper, surface of carbon felt electrodes were treated with various concentrations of grephene oxide. Electrochemical analysis, cyclic voltammetry (CV), was performed to investigate redox characteristics as electrode for VRFB. Also the effect of GO on the introduction of functional group on the surface of carbon felt electrodes were investigated using X-ray photoelectron spectroscopy (XPS), which discovered increase in the overall functional group content on the surface of carbon felts.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.71-77
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• 2022

To increase biomass utilization, rice husk-based activated carbon (RHAC) followed by nitrogen plasma surface treatment was prepared and the electric double-layer capacitor performance was investigated. Through nitrogen plasma surface treatment, up to 2.17% of nitrogen was introduced to the surface of RHAC, and in particular the sample reacted for 5 min with nitrogen plasma showed dominant formation of pyrrolic/pyridine N functional groups. In addition, mesopores were formed on the RHAC material by the removal of silica, and the surface roughness of the carbon material increased by nitrogen plasma surface treatment, resulting in the formation of many micropores. As a result of cyclic voltammetry measurement, at a scan rate of 5 mV/s, the specific capacitance of the RHAC treated with nitrogen plasma increased up to 200 F/g, showing an 80.2% improvement compared to that of using untreated RHAC (111 F/g). This is attributed to the synergetic effect of the introduction of pyrrolic/pyridine-based nitrogen functional groups and the increase of the micropore volume on the surface of the carbon material. This study has a positive effect on the environment in terms of recycling waste resources and using plasma surface treatment.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.586-590
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• 2006

As one of electro active polymers for soft smart materials, the ionic polymer metal composites (IPMC) are easy to produce through chemical reduction processing and show high displacements at low voltage. When the IPMC actuates, the deformation depends on a few factors including the structure of based membrane, species and morphology of the metal electrodes, the nature of cations and the level of hydration. As previously published, we have been studying on improvement of actuation through surface electrode modification of IPMC to grasp the effect of electrode morphology on actuation. This study is comparative experiments through the chemical reaction and deposition by ion beam assisted deposition (IBAD) in order to prepare the very thin and homogeneous surface electrode of IPMC. The IPMCs were prepared with different surface roughness of polymer membrane, and the influence of the surface roughness on the actuation was studied. By investigating the electrical properties and driving displacement, the actuating properties of IPMC with different surface roughness were studied.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.463-466
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• 2006

직접 알콜 연료전지는 액체인 알콜을 직접 연료전지에 공급하여 연소시킴으로써 높은 효율을 갖는 휴대용전원으로 주목받는 장치이다. 직접 알콜 연료전지에 담지체로 사용되는 탄소 소재는 넓은 표면적과 우수한 전기전도도를 가지고 있다는 장점 있으나 금속 촉매와의 상호작용이 약하여 촉매 활성에 영향을 주지 못한다. 산화물을 담지체로 사용할 경우 이러한 금속-담지체 간의 상호작용으로 인한 촉매활성 증가 및 입자성장 억제의 효과를 기대할 수 있다. 본 연구에서는, 안티몬 도핑된 주석산화물 (Sb-doped SnO2 : ATO nanoparticle)을 직접 메탄올 연료전지용 담지체어 적용하였으며 합성 과정은 다음과 같다. SnC14 5H2O SbC13, NaOH, HCl 수용액 혼합물을 삼구 플라스크에 넣고 $100^{\circ}C$ 온도에서 환류(reflux) 시킨 후 세척 및 건조하여 Air 분위기에서 열처리하였다. 합성된 산화물 수용액에 폴리올 방법으로 합성된 백금 콜로이드를 담지하였으며, 세척과 건조를 통하여 산화물에 담지된 백금 촉매를 촉매를 합성하였다. 촉매의 구조분석을 위해 XRD, TEM을 사용하였으며, 전극촉매로서의 활성을 평가하기 위해 cyclic voltammetry을 평가하였다. 본 연구에서는 백금의 담지량에 따른 Costripping voltammetry특성과 메탄올 및 에탄올 산화 반응 특성에 대하여, 탄소를 담지체로 사용한 Pt/C 촉매와 비교 평가하였다. 알콜 산화반응 평가결과, 주석산화물에 담지한 촉매가 탄소를 담지체로 사용한 촉매보다 우수한 활성을 나타내었으며 활성증가는 메탄올에 비해 에탄올 산화 반응의 경우 크게 증가하였다. 막과 비교해 보았다. $ZrO_2$ 입자는 전도성이며 동시에 친수성을 나타내기 때문에 상용 막에 비하여 함수율 및 수소이온 전도도가 우수하게 나타났다. 복합막의 이러한 물성은 $100^{\circ}C$이상의 고온에서 전해질 막 내의 물 관리를 용이하게 한다. 단위 전지 운전 온도 $130^{\circ}C$, 상대습도 37%의 운전 조건에서도 상당히 우수한 전지 성능을 보임에 따라 고온/저가습 조건에서 상용 Nafion 112 막보다 우수한 막 특성을 나타냄을 확인하였다.소/배후방사능비는 각각 $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45$ 그리고 $5.59{\pm}0.40$이었고, $^{67}Ga$-citrate의 경우 2시간, 24시간, 48시간에 $3.06{\pm}0.84,\;4.12{\pm}0.54\;4.55{\pm}0.74 $이었다. 결론 : Transferrin에 $^{99m}Tc$을 이용한 방사성표지가 성공적으로 이루어졌고, $^{99m}Tc$-transferrin의 표지효율은 8시간까지 95% 이상의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$<

• Proceedings of the Korean Printing Society Conference
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• 2001.06a
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• pp.46-60
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• 2001

본 연구는 전기화학적으로 제조된 초환원수 수용액을 탈묵에 적용하기 위한 연구로서 수용액의 알카리도가 고지의 젖음성에 미치는 영향과 그에 따른 탈묵성에 미치는 영향을 고찰한 것이다. 초 환원수는 고전압 하에서 순수 물을 전기적으로 분해한 것으로서 양극에서 pH가 약 11이상의 것을 얻어 사용하였다. 물의 알칼리도에 따라서 탈묵제가 펄플에 젖음성의 영향을 살펴보았으며, 특히 펄프 입자의 표면 전하에 큰 영향을 미쳤다. 이에 따라서 잉크 입자의 탈착이 효과적으로 진행됨이 관찰되었으며, 탈착된 잉크 입자의 크기도 탈묵에 적절함으로서 탈묵 효과가 향상되었다. 이러한 현상을 사용된 계면활성제, 물의 알카리도, 펄프 및 잉크의 표면 전화, 친수/소수화도 등과 비교 검토하였다.

• 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.