學校長의 變革的 指導性과 敎師의 職務滿足度의 關係

Kwak Dae Sub(郭大燮) 공주대학교 교육연구소 1998 교육연구 Vol.14 No.-

This study was started for the purpose of identifying the relationship between principals’ transformational leadership and teachers’ job-satisfaction in primary schools. As a result, it was found that the higher the level of transformational leadership of principals, the stronger the teachers’ job-satisfaction, and that the ‘human respect’ factor of the three sub-factors of transformational leadership was the most predictable one to the level of teachers’ job-satisfaction.

Inkjet‐Printable Nanoporous Ag Disk Arrays Enabling Coffee‐Ring Effect‐Driven Analyte Enrichment Towards Practical SERS Applications

Jung-Sub Wi,Jeong Dae Kim,Wonseok Lee,Hyunsik Choi,Minjeong Kwak,Jungkeun Song,Tae Geol Lee,Jong G. Ok 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.2

To make surface enhanced Raman scattering (SERS) sensors more practical, we propose nanoporous Ag disks as SERSactive plasmonic structures that can be readily inkjet-printed just before use to avoid degradation of SERS enhancement. Together with the aid of the enhanced plasmonic fi elds from the nanoporous Ag (confirmed by electromagnetic simulation), we utilize a coffee-ring effect to concentrate target analytes, which is demonstrated by confocal Raman measurements. By using the proposed SERS sensor, Raman signals of TiO 2 nanoparticles with a concentration of ppm to sub-ppb have been successfully measured. TiO 2 in commercial consumables has been also detected by distinguishing its crystalline phase.

바른체형운동 지도가 정신장애인의 우울감 및 폐활량에 미치는 효과

우경희(Kyung-Hee Woo),양정옥(Jeong-Ok Yang),이중숙(Joong-Sook Lee),이범진(Bom-Jin Lee),김의숙(Eui-Suk Kim),정숙희(Sook-Hee Jung),곽이섭(Yi-Sub Kwak) 한국생명과학회 2016 생명과학회지 Vol.26 No.10

본 연구는 바른체형운동 프로그램이 정신장애인의 폐활량 및 우울감에 미치는 영향을 알아보고자 경북 P시에 거주하고 정신장애 판정을 받았으며 정신재활프로그램에 참여하는 정신장애인을 대상으로 실시하였다. 참여한 피험자에게 연구목적과 내용을 설명하였고, 연구 참가동의서를 받은 19명을 최종 선정하여 10명은 운동군, 9명은 통제군으로 분류하여 12주간 바른체형운동 프로그램을 실시하였고, 연구결과는 다음과 같다. 우선 폐활량의 변화를 살펴본 결과 PEF (최대호기속도)와 FEV1/FVC (1초간 노력성 호기량의 노력성 폐활량에 대한 비)가 바른체형운동 적용 후에 증가하여 호기기능이 유의하게 향상됨을 확인하였다. 또한, 바른체형운동 프로그램 참여에 따른 운동군의 우울감의 변화는 통계적으로 유의한 차이는 나타나지 않았으나 우울정도의 감소폭이 통제군보다 운동군에서 훨씬 크게 나타나 바른체형운동이 정신장애인의 우울감 정도의 감소에 긍정적인 변화를 나타냈다고 할 수 있다. 그리고 본 연구에서는 프로그램 참가자들의 특수성으로 인한 표본 수의 한계로 인해 통계적 검증의 한계가 명확히 존재함을 고려하여 참여자들의 주관적 경험을 심층적으로 이해하는 것을 목적으로 한 질적분석(qualitative research)을 병행하여 실시하였다. 프로그램 참가자 중 동의하는 사람에 한해 심층적 면담을 실시하였으며 이를 통해 참여자들이 표현하는 내용의 의미단위를 검토하여 분류하고 세분화하는 작업을 통해 주제분석(thematic analysis)을 실시한 결과, 전반적으로 바른체형운동 프로그램에 참여한 정신장애인들의 우울감 정도가 줄어든 것을 알 수 있었다. 우울감의 변화과정은 ‘변화의 시작’, ‘프로그램에 대한 흥미’, ‘신체적 건강의 필요성에 대한 인식’, ’신체적 건강증진’, ’신체적 기능의 회복’, ’부정적인 습관(자세)의 변화’, ’우울감의 감소’, ’할 수 있다는 자신감’, ’미래에 대한 희망’과 같은 3개의 주제와 6개의 하위 주제로 나타났다. 따라서 바른체형운동이 정신장애인들의 신체적 건강증진을 위해 심폐지구력을 높여 신체적 건강증진을 도모할 뿐 아니라 더 나아가 정신적 우울감의 감소에도 효과성을 높여 정신적 건강증진에도 도움을 줄 수 있는 프로그램으로 정신장애인의 삶의 질 증진을 위해서는 보급이 반드시 필요할 것으로 사료된다. The purpose of this study was to investigate the effects of the regular Upright Body Type Excercise on posture, muscle strength of leg, lung capacity and depression of people with mental illness. The subjects of this study were recruited from B mental health center (5 years and more mental illness patients, n=19) located in P city. For the exercise group, They were carried out the Upright Body Type Excercise Program during 8 weeks (60 min/time, 3 times/week). They were randomly divided into two groups. Exercise group (n=10) and Control group (n=9). And also, they were agreed with consent forms before the experiments. Research results were as follows. Through the upper body type exercise, there was significantly difference in PEF and FEV1/FVC in the trained group. And also, there was much improved in depression level in the trained group. The change of melancholy feeling before and after the program was not statistically significant. However, because of limitations of sampling size due to the peculiarities of the program participants, in consideration of the limit of statistical validation exists clearly, intended to better understand the subjective experience of attendees, qualitative analyzing(qualitative research) was carried out in parallel. It was conducted a deep interview only person accepted among program participants, thematic analysis, subject analysis tasks to be subdivided by classifying by considering the semantic units of what participants expressed, was thus carried out. It found that the degree of melancholy feeling of mental disorders who participated in the Upright Body Typed Exercise Program was reduced. The course of the experience of change in depression appered the three subjects and six sub-themes such as “the start of the change”, “interest of the program”, “recognition of the need of the body`s health”, “physical health promotion”, “recovery of physical function”, “negative change of habits (attitude)”, “reduction of sense of depression”, “confidence that it is possible to”, “hope for the future”. Therefore, upper body type exercise is much helpful in lung capacity and mental health of people with mental illness. So, this type of exercise mostly needed in the people with mental illness group than the other group for the quality of life.

Improvement of reduction and oxidation performance of MMgOx (M=Fe, Co, Ni, and Cu) particles for chemical looping combustion

Kwak, Byeong Sub,Park, No-Kuk,Baek, Jeom-In,Ryu, Ho-Jung,Kang, Misook Elsevier 2017 Powder technology Vol.312 No.-

<P><B>Abstract</B></P> <P>The objective of this study was to use Mg to improve the performance in chemical looping combustion. Oxygen carrier particles were synthesized in which Mg was doped into the M-sites with Fe, Co, Ni, and Cu to produce FeaMgbOx, CoaMgbOx, NiaMgbOx, and CuaMgbOx, respectively, with M/Mg ratios ranging from 1.5 to 3.0. The structure and properties of the prepared samples were characterized using XRD, SEM, CH<SUB>4</SUB>-/CO-TPD, XPS, and TGA. The XRD results explore that the Fe2Mg1Ox sample has a pure cubic structure of Fe<SUB>2</SUB>MgO<SUB>4</SUB>, whereas the Co2Mg1Ox and Ni2Mg1Ox samples exist as a solid solution. Nevertheless, the mixed compound formation of orthorhombic structure of Cu<SUB>2</SUB>MgO<SUB>3</SUB> and cubic structure of MgO has been observed in Cu2Mg1Ox. The CH<SUB>4</SUB> absorption is the highest on the Cu2Mg1Ox sample according to the CH<SUB>4</SUB>-TPD results. The CO-TPD and H<SUB>2</SUB>–TPR results showed that the adsorption of the Cu and Mg complex metal oxide is higher than that of the pure metal oxide. The oxygen carrier capacity of the samples was studied by isothermal H<SUB>2</SUB> (FR)/air (AR) and CH<SUB>4</SUB> (FR)/air (AR) redox cycle experiments at 850°C using TGA. The promising results obtained from chemical looping combustion indicate that the CuaMgbOx samples are potentially useful for CLC in H<SUB>2</SUB> and CH<SUB>4</SUB> atmospheres.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Redox performance for MaMgbOx (M=Fe, Co, Ni, and Cu) was investigated in detail. </LI> <LI> The highest redox performance (15.29wt%) was observed for Cu2.0Mg1.0Ox. </LI> <LI> The Cu2.0Mg1.0Ox sample was stable up to 10 reaction cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Redox reaction on the M2.0Mg1.0Ox (M=Fe, Co, Ni, and Cu) for the chemical looping combustion.</P> <P>[DISPLAY OMISSION]</P>

Reduction and oxidation performance evaluation of manganese-based iron, cobalt, nickel, and copper bimetallic oxide oxygen carriers for chemical-looping combustion

Sub Kwak, Byeong,Park, No-Kuk,Ryu, Ho-Jung,Baek, Jeom-In,Kang, Misook Elsevier 2018 Applied Thermal Engineering Vol.128 No.-

<P><B>Abstract</B></P> <P>Transition metal oxides like Fe<SUB>2</SUB>O<SUB>3</SUB>, Co<SUB>3</SUB>O<SUB>4</SUB>, NiO, and CuO have mainly been used in the chemical-looping combustion (CLC) reaction as oxygen carrier particles because of their outstanding performances due to high reduction potential. However, monometal oxides have a serious problem of rapid deactivation due to agglomeration between each particle after several redox cycles. In order to solve this problem, bimetal oxides based on Mn, which undergoes no deactivation, were synthesized. Mn-based bimetal oxygen carrier particles Fea-Mnb-Ox, Coa-Mnb-Ox, Nia-Mnb-Ox, and Cua-Mnb-Ox were synthesized by using a sol–gel method. The range of a and b in the particle label obtained in this study is 0.5–2.5, depending on the metal content added. The chemical and physical properties of the prepared particles were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), CH<SUB>4</SUB>-/CO-temperature programmed desorption, and thermogravimetric analysis (TGA). The XRD results showed that the prepared particles comprised two- or three-phase mixed metal oxides. The Fe2.0-Mn1.0-Ox particle was in the phases of Fe<SUB>2</SUB>Mn<SUB>1</SUB>O<SUB>4</SUB> and Fe<SUB>20.16</SUB>Mn<SUB>11.84</SUB>O<SUB>48</SUB>, respectively, and the Co2.0-Mn1.0-Ox particle had the phase of Co<SUB>2</SUB>Mn<SUB>1</SUB>O<SUB>4</SUB>. In addition, Ni2.0-Mn1.0-Ox particle has NiO and Ni<SUB>1</SUB>Mn<SUB>2</SUB>O<SUB>4</SUB> phases, and Cu2.0-Mn1.0-Ox particle exist in the phases of CuO, Cu<SUB>2</SUB>O and Cu<SUB>1</SUB>Mn<SUB>1</SUB>O<SUB>2</SUB>, respectively. The distributions of added elements on the particles were observed from the SEM mapping results. The oxygen carrier capacities of the particles were tested by isothermal H<SUB>2</SUB>/air and CH<SUB>4</SUB>/air redox cycle experiments using TGA at 850°C. The improved results obtained in this study revealed that the Cu2.0-Mn1.0-Ox particle was an enhanced bimetal oxide oxygen carrier for CLC under CH<SUB>4</SUB>/air conditions. In particular, among the synthesized particles, the Cu2.0-Mn1.0-Ox particle stably showed 16.7wt% oxygen transfer capacity over 10 redox cycle under CH<SUB>4</SUB>/air at 850°C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Redox performance for Ma-Mnb-Ox (M=Fe, Co, Ni, and Cu) investigated in detail. </LI> <LI> The highest redox performance (16.7wt%) was observed for Cu2.0-Mg1.0-Ox. </LI> <LI> The Cu2.0-Mn1.0-Ox sample was stable up to 10 reaction cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Redox reaction on the Cua-Mnb-Ox for the chemical looping combustion.</P> <P>[DISPLAY OMISSION]</P>

Synthesis of basalt fiber@Zn_1-xMg_xO core/shell nanostructures for selective photoreduction of CO₂ to CO

Kwak, Byeong Sub,Kim, Kang Min,Park, Sun-Min,Kang, Misook Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.407 No.-

<P><B>Abstract</B></P> <P>This study focused on the development of a catalyst for converting carbon dioxide, the main cause of global warming, into a beneficial energy source. Core@shell structured particles, BF@ZnO and BF@Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O, are synthesized in order to selectively obtain CO gas from the photoreduction of CO<SUB>2</SUB>. A modified sol-gel process is used to synthesize the core@shell structures with a three-dimensional microstructure, which are subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), ultraviolet (UV)–vis absorption, photoluminescence (PL), and photocurrent density analysis. The CO<SUB>2</SUB> adsorption abilities of the core@shell particles are estimated through CO<SUB>2</SUB>-temperature programmed desorption (TPD). The core@shell structured BF@Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O particles including the Mg ingredient significantly increased the adsorption of CO<SUB>2</SUB> gas at the microfiber/nanoparticle interface. Both the BF@ZnO and BF@Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O particles selectively reduce the carbon dioxide to carbon monoxide, with almost no other reduced products being observed. These results are attributed to the effective adsorption of CO<SUB>2</SUB> gas and inhibited recombination of the photogenerated electron–hole pairs. BF@Zn<SUB>0.75</SUB>Mg<SUB>0.25</SUB>O exhibited superior photocatalytic behavior and selectively produced 5.0μmolg<SUB>cat</SUB> <SUP>−1</SUP> L<SUP>−1</SUP> of CO gas after 8h of reaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO and Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O crystals were grown onto the BFs. </LI> <LI> The core@shell structured BF@Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O particles significantly increased the adsorption of CO<SUB>2</SUB> gas. </LI> <LI> The BF@ZnO or BF@Zn<SUB>1-x</SUB>Mg<SUB>x</SUB>O particles selectively reduce the carbon dioxide to carbon monoxide. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effective hydrogen production from ethanol steam reforming using CoMg co-doped SiO₂@Co_1−xMg_xO catalyst

Kim, Kang Min,Kwak, Byeong Sub,Im, Younghwan,Park, No-Kuk,Lee, Tae Jin,Lee, Sang Tae,Kang, Misook Elsevier 2017 Journal of industrial and engineering chemistry Vol.51 No.-

<P><B>Abstract</B></P> <P>In this study, the activities of core@shell-structured SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O catalysts in ethanol steam reforming (ESR) were investigated, and the promotion effect of Mg upon H<SUB>2</SUB> production was assessed. The loading of SiO<SUB>2</SUB>@CoO with Mg resulted in an increase in ethanol conversion and H<SUB>2</SUB> yield with the concomitant suppression of carbon coke deposition and CO emission. Oxygen transfer from the MgO supporter (or improver) to the main cobalt catalytic species during ESR might play a role in maintaining the partially oxidized Co state. In longevity tests, the SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O core@shell material, despite being reused three times, exhibited superior H<SUB>2</SUB> production for 100h without structural collapse or coke formation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The core@shell structured SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O was prepared. </LI> <LI> CO-WGS on the core@shell structured SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O was promoted. </LI> <LI> Carbon coke deposition was suppressed by Mg loading. </LI> <LI> Both Co<SUP>0</SUP> and Co<SUP>2+</SUP> played the active sites on SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O. </LI> <LI> SiO<SUB>2</SUB>@Co<SUB>1−x</SUB>Mg<SUB>x</SUB>O exhibited high hydrogen production. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of acidity on the performance of a Ni-based catalyst for hydrogen production through propane steam reforming: K-AlSi_<i>x</i>O_<i>y</i> support with different Si/Al ratios

Do, Jeong Yeon,Kwak, Byeong Sub,Park, No-Kuk,Lee, Tae Jin,Lee, Sang Tae,Jo, Seung Won,Cha, Moon Soon,Jeon, Min-Kyu,Kang, Misook Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.36

<P><B>Abstract</B></P> <P>Propane steam reforming (PSR) for the production of H<SUB>2</SUB> was catalyzed by a NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalyst synthesized with various Si/Al ratios (Si/Al = 0, 0.3, 0.5, 0.7, and 1.0). The effect of the Si/Al ratio on the acidity of the NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalyst for PSR was investigated. NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> gave a higher H<SUB>2</SUB> selectivity and stability during PSR than NiO/K-SiO<SUB>2</SUB> and NiO/K-Al<SUB>2</SUB>O<SUB>3</SUB>. The NH<SUB>3</SUB>-TPD results showed that the acid quantity and strength of NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> changed significantly depending on the Si/Al ratio. With an increased Si/Al ratio, the densities of both weak and strong acid sites increased. The C<SUB>3</SUB>H<SUB>8</SUB>- and CO-TPD results indicated that desorption amounts increased significantly in all NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalysts relative to those of NiO/K-SiO<SUB>2</SUB> and NiO/K-Al<SUB>2</SUB>O<SUB>3</SUB>, and the adsorption amount increased with the Si/Al ratio. PSR results showed that the NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalyst exhibited much better stability than the NiO/K-SiO<SUB>2</SUB> and NiO/K-Al<SUB>2</SUB>O<SUB>3</SUB> catalysts. This study confirms the following facts: when the acidity is appropriately adjusted for the catalyst, adsorption of the reaction gas increases, which eventually increases the reaction rate and also inhibits strong sintering between the nickel and the Al<SUB>2</SUB>O<SUB>3</SUB> support. As a result, deterioration of the catalyst can be reduced.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalyst was synthesized for the production of H<SUB>2</SUB> from PRS. </LI> <LI> The acid quantity and strength of NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> changed significantly depending on the Si/Al ratio. </LI> <LI> The adsorptions of C<SUB>3</SUB>H<SUB>8</SUB> and CO increased with the Si/Al ratio. </LI> <LI> The NiO/K-AlSi<SUB> <I>x</I> </SUB>O<SUB> <I>y</I> </SUB> catalyst exhibited much better stability during PSR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Reliable oxygen transfer in MgAl₂O₄ spinel through the reversible formation of oxygen vacancies by Cu²⁺/Fe³⁺ anchoring

Do, Jeong Yeon,Son, Namgyu,Park, No-Kuk,Kwak, Byeong Sub,Baek, Jeom-In,Ryu, Ho-Jung,Kang, Misook Elsevier 2018 APPLIED ENERGY Vol.219 No.-

<P><B>Abstract</B></P> <P>This study focused on Cu<SUB>x</SUB>Mg<SUB>1-x</SUB>Fe<SUB>y</SUB>Al<SUB>2-y</SUB>O<SUB>4</SUB> oxygen carriers for application in the chemical looping combustion of methane. Cu<SUB>x</SUB>Mg<SUB>1-x</SUB>Fe<SUB>y</SUB>Al<SUB>2-y</SUB>O<SUB>4</SUB> was fabricated by simultaneously substituting Mg<SUP>2+</SUP> and Al<SUP>3+</SUP> with Cu<SUP>2+</SUP> and Fe<SUP>3+</SUP> in the spinel structure of MgAl<SUB>2</SUB>O<SUB>4</SUB>. As a result, a great synergistic effect was observed: Cu<SUB>0.75</SUB>Mg<SUB>0.25</SUB>Fe<SUB>1.5</SUB>Al<SUB>0.5</SUB>O<SUB>4</SUB> exhibited 7.85% oxygen transfer capacity in the CH<SUB>4</SUB>-CO<SUB>2</SUB>/air redox system. Methane and carbon monoxide were significantly adsorbed on the surface of the Cu<SUB>x</SUB>Mg<SUB>1-x</SUB>Fe<SUB>y</SUB>Al<SUB>2-y</SUB>O<SUB>4</SUB> particles. Cyclic voltammetry studies predicted the active lifetime of the oxygen carrier, which had not been reported until now. Cu<SUB>0.75</SUB>Mg<SUB>0.25</SUB>Fe<SUB>1.5</SUB>Al<SUB>0.5</SUB>O<SUB>4</SUB> was expected to exhibit the greatest oxygen transfer capacity after 300 redox cycles and maintain an oxygen transfer efficiency of 92% until the 1000th redox cycle in the H<SUB>2</SUB>-N<SUB>2</SUB>/air redox system. This study concluded that the active metal species, containing Cu<SUP>2+</SUP> and Fe<SUP>3+</SUP> ions, were stably anchored in the spinel structure; this led to the reversible formation of oxygen vacancies in the spinel structure, resulting in an excellent oxygen transfer capacity that could be maintained for a long time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu<SUB>x</SUB>Mg<SUB>1-x</SUB>Fe<SUB>y</SUB>Al<SUB>2-y</SUB>O<SUB>4</SUB> spinel structured oxygen carriers were successfully prepared. </LI> <LI> Reversible oxygen vacancies were observed in a Cu<SUB>x</SUB>Mg<SUB>1-x</SUB>Fe<SUB>y</SUB>Al<SUB>2-y</SUB>O<SUB>4</SUB> spinel structure. </LI> <LI> CH<SUB>4</SUB> and CO gases were much adsorbed on the surface of Cu<SUB>0.75</SUB>Mg<SUB>0.25</SUB>Fe<SUB>1.5</SUB>Al<SUB>0.5</SUB>O<SUB>4</SUB> spinel particle. </LI> <LI> The greatest oxygen transfer in Cu<SUB>0.75</SUB>Mg<SUB>0.25</SUB>Fe<SUB>1.5</SUB>Al<SUB>0.5</SUB>O<SUB>4</SUB> particle was obtained. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Reliable oxygen transfer in MgAl<SUB>2</SUB>O<SUB>4</SUB> spinel through the reversible formation of oxygen vacancies by Cu<SUP>2+</SUP>/Fe<SUP>3+</SUP> anchoring.</P> <P>[DISPLAY OMISSION]</P>

ZnO를 이용한 광 전기화학적 수소제조 반응 시 Ag 첨가 영향

곽병섭 ( Byeong Sub Kwak ),김성일 ( Sung-il Kim ),강미숙 ( Misook Kang ) 한국공업화학회 2017 공업화학 Vol.28 No.2

본 연구에서는 공침법을 이용해 ZnO를 합성하였고, 촉매의 성능을 개선하고자 Ag를 첨가하였다. 합성한 촉매의 물리 화학적 특성은 X-선 회절분석(XRD), 자외선-가시선 분광광도계(UV-visible spectroscopy), 전자주사현미경(SEM), 에너지 분산형 분광분석법(EDS), 광 발광(photoluminescence), 광 전류 측정(photocurrent)을 이용해 확인하였다. 촉매는 물과 메탄올 분해로부터 수소 제조를 통해 성능을 평가하였다. 그 결과 전자 캡쳐 역할을 하는 Ag 첨가로 인해 들뜬 전자와 정공 사이의 재결합이 줄어들어 촉매의 성능이 향상되었으며, 특히 0.50 mol% Ag/ZnO 촉매를 사용하였을 때 10 h 반응 후 8.60 μmol g^-1의 수소가 발생하였다. In this study, ZnO, which is widely known as a non TiO2 photocatalyst, was synthesized using coprecipitation method and Ag was added in order to improve the catalytic performance. The physicochemical characteristics of the synthesized ZnO and Ag/ZnO particles were checked using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), and photocurrent measurements. The performance of catalysts was tested by H₂ production using the photolysis of H₂O with MeOH. By adding Ag which plays a role as an electron capture on the ZnO catalyst, the performance increased due to the recombination of excited electrons and holes. In particular, 8.60 μmol g^-1 H₂ was produced after 10 h reaction over the 0.50 mol% Ag/ZnO.