• 한국환경복원기술학회지
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• 제12권2호
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• pp.95-105
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• 2009

Land Use Changes (LUCs) have effects on greenhouse gas emissions and carbon stocks in soil and vegetation. Therefore, predictions for LUC are very important for achieving quantitative targets of $CO_2$ reduction rates. Some research exists on carbon fluxes and carbon cycles to estimate carbon stocks in terrestrial ecosystems in Korea. However, these researches have limitations in terms of helping us understand future potential reductions of $CO_2$ that reflect the influence of LUC. The aim of this study is to analyze the reduction levels of $CO_2$ emissions while considering LUC scenarios that effect carbon fluxes for LCS basic study in the year 2030. In this study, a common approach to model the effects of LUC on carbon stocks is the use of CA-Markov technical process with LUC patterns in the past. Potential reduction of $CO_2$ is calculated by change of land use that contains different soil organic carbon, each land use type, and biomass in vegetation. An IPCC analytical method of natural carbon sink and coefficient results from previous study in Korea is used as a calculation method for potential reduction of $CO_2$. As a result, 12,419 KtC will be reduced annually, which is 8.3% percent of 2005 $CO_2$ emissions in Korea. This will result in 3,226 hundred million won of economic efficiency. In conclusion, conservation of natural carbon sinks is necessary even if the amount of potential reduction change is little.

• 환경영향평가
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• 제21권3호
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• pp.409-415
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• 2012

Post-kyoto regime has been discussing with the GHG reduction commitment. GHG energy target management system also has been applied for the domestic measures in the country. Universities are major emission sources for GHG. It is very important for campus to built the GHG inventory system and estimate the potential GHG emission reduction. In general, GHG inventory on the campus was taken by the IPCC guidance with the classification of scope 1, 2, and 3. Electricity was the highest portion of GHG emission on the campus as 5,053.90 $tonsCO_2eq/yr$ in 2009. Manufacturing sector was the second high emission and meant GHG in laboratory. Potential GHG reduction was planned by several assumptions such as installation of occupancy sensor, exchanging LED lamp and photovoltaic power generation. These reduction scenarios was simulated by LEAP model. In 2020, outlook of GHG emission was estimated by 17,435.98 tons of $CO_2$ without any plans of reduction. If the reduction scenarios was applied in 2020, GHG emission would be 16,507.60 tons of $CO_2$ as 5.3% potential reduction.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1763-1768
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• 2006

The application of poly(Co(II)-(1,8-diaminonaphthalene))(poly(Co-DAN)) and poly(1,8-diaminonaphthalene) (Poly(1,8-DAN)) to the electrocatalytic reduction of molecular oxygen was investigated, which were electrochemically grown by the potential cycling method on the glassy carbon electrodes. The reduction of oxygen at the polymer and its metal complex polymer coated electrodes were irreversible and diffusion controlled. The Poly(1,8-DAN) and Poly(Co-DAN) films revealed the potential shifts for the oxygen reduction to 30 mV and 110 mV, respectively, in an aqueous solution, compared with that of the bare electrode. Hydrodynamic voltammetry with a rotating ring-disk electrode showed that Poly(1,8-DAN) and Poly(Co-DAN) coated electrodes converted respectively 84% and 22% of $O_2$ to $H_2O$ via a four electron reduction pathway.

• Bulletin of the Korean Chemical Society
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• 제19권8호
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• pp.825-830
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• 1998

The electrocatalytic reduction of dioxygen by Co(TTFP)(Y)2 {Y=H2O or HO-} is investigated by cyclic voltammetry, spectroelectrochemistry, hydrodynamic voltammetry at a glassy carbon electrode in dioxygen-saturated aqueous solutions. Electrocatalytic reduction of dioxygen by CoⅡ(TTFP)(Y)2 establishes a pathway of 2e- reduction to form hydrogen peroxide, and then the generated hydrogen peroxide is reduced to water by CoⅠ(TTFP)(Y)2 at more negative potential. CoⅡ(TTFP)(Y)2 may bind dioxygen to produce the adduct complex [CoⅡ-O2 or CoⅢ-O2] which exhibits a Soret band at 411 nm and Q band at 531 nm.

• Journal of Forest and Environmental Science
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• 제34권6호
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• pp.461-471
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• 2018

In this study, the deforestation and forest degradation areas have been obtained in Myanmar using a land cover lamp (LCM) and a tree cover map (TCM) to get the $CO_2$ potential reduction and the strength of occurrence was evaluated by using the geostatistical technique. By applying a multiple criteria decision-making method to the regions having high strength of occurrence for the $CO_2$ potential reduction for the deforestation and forest degradation areas, the priority was selected for candidate lands for REDD+ project. The areas of deforestation and forest degradation were 609,690ha and 43,515ha each from 2010 to 2015. By township, Mong Kung had the highest among the area of deforestation with 3,069ha while Thlangtlang had the highest in the area of forest degradation with 9,213 ha. The number of $CO_2$ potential reduction hotspot areas among the deforestation areas was 15, taking up the $CO_2$ potential reduction of 192,000 ton in average, which is 6 times higher than that of all target areas. Especially, the township of Hsipaw inside the Shan region had a $CO_2$ potential reduction of about 772,000 tons, the largest reduction potential among the hotpot areas. There were many $CO_2$ potential reduction hot spot areas among the forest degradation area in the eastern part of the target region and has the $CO_2$ potential reduction of 1,164,000 tons, which was 27 times higher than that of the total area. AHP importance analysis showed that the topographic characteristic was 0.41 (0.40 for height from surface, 0.29 for the slope and 0.31 for the distance from water area) while the geographical characteristic was 0.59 (0.56 for the distance from road, 0.56 for the distance from settlement area and 0.19 for the distance from Capital). Yawunghwe, Kalaw, and Hsi Hseng were selected as the preferred locations for the REDD+ candidate region for the deforestation area while Einme, Tiddim, and Falam were selected as the preferred locations for the forest degradation area.

• KIEAE Journal
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• 제14권2호
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• pp.87-98
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• 2014

This study is to identify quantitatively the function of carbon dioxide emissions reduction due to temperature and energy reduction according to direct carbon dioxide storage, shade provision, and evaportanspiration of urban park. According to the result of study, landscape tree indicated high carbon dioxide storage effect compare to bush, in which broadleaf tree indicated higher storage function than coniferous tree. It is believed to be the storage of carbon dioxide can be increased by increasing the composition rate of forest plants in the urban park. According to the direct estimation result of carbon dioxide storage in terms of example area, storage of carbon dioxide is estimated to be "seoul a zone" $476,818.8kg{\cdot}CO_2/m^2yr$, "anyang b zone" $186,435.7{\cdot}CO_2/m^2yr$, "daejeon c zone" $262,826{\cdot}CO_2/m^2yr$, "kwangju d zone" $231,657.8{\cdot}CO_2/m^2yr$. The carbon dioxide storage per unit area estimated to be "seoul a zone" $3.4{\cdot}CO_2/m^2yr$, "anyang b zone" $5.0{\cdot}CO_2/m^2yr$, "daejeon c zone" $2.6{\cdot}CO_2/m^2yr$, "kwangju d zone" $5.6{\cdot}CO_2/m^2yr$. The result of indirect carbon dioxide reduction effect estimated to be "seoul a zone" $291,603.4{\cdot}CO_2/m^2yr$, "anyang b zone" $165,462.4{\cdot}CO_2/m^2yr$, "daejeon c zone" $141,719.2{\cdot}CO_2/m^2yr$, "kwangju d zone" $154,803.4{\cdot}CO_2/m^2yr$. Carbon dioxide reduction potential amount through the urban park was increased to 1.6 times to 1.8 times when calculated to the indirect effect.

• Journal of Electrochemical Science and Technology
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• 제6권3호
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• pp.106-110
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• 2015

This study investigates Cu(II) complexes of cyclam, propylene cross-bridged cyclam (PCB-cyclam), and propylene cross-bridged cyclam diacetate (PCB-TE2A) as homogeneous electrocatalysts for CO₂ reduction in comparison with Ni(II)-cyclam. It is found that Cu(II)-cyclam can catalyze CO₂ reduction at the potential close to its thermodynamic value (0.75 V vs. Ag/AgCl) in tris-HCl buffer (pH 8.45) on a glassy carbon electrode. Cu(II)-cyclam, however, suffers from severe demetalation due to the insufficient stability of Cu(I)-cyclam. Cu(II)-PCB-cyclam and Cu(II)-PCB-TE2A are revealed to exhibit much less demetalation behavior, but poor CO₂ reduction activities as well. The inferior electrocatalytic ability of Cu(II)-PCB-cyclam is ascribed to its redox potential that is too high for CO₂ reduction, and that of Cu(II)-PCB-TE2A to the steric hindrance preventing facile contact with CO₂ molecules. This study suggests that in addition to the redox potential and chemical stability, the stereochemical aspect has to be considered in designing efficient electrocatalysts for CO₂ reduction.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.11-17
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• 2020

Copper has been proved to be the best catalyst for electrochemical CO2 reduction reaction, however, for optimal efficiency and selectivity, its performance requires improvements. Electrochemical CO2 reduction reaction (RR) using CuO nanowire electrode was performed with different concentrations of KHCO3 electrolyte (0.1 M, 0.5 M, and 1 M). Cu(OH)2 was formed on Cu foil, followed by thermal-treatment at 200℃ under the air atmosphere for 2 hrs to transform it to the crystalline phase of CuO. We evaluated the effects of different KHCO3 electrolyte concentrations on electrochemical CO2 reduction reaction (RR) using the CuO nanowire electrode. At a constant current (5mA), low concentrated bicarbonate exhibited a more negative potential -0.77 V vs. Reversible Hydrogen Electrode (RHE) (briefly abbreviated as VRHE), while the negative potential reduced to -0.33 VRHE in the high concentration of bicarbonate solution. Production of H2 and CH4 increased with an increased concentration of electrolyte (KHCO3). CH4 production efficiency was high at low negative potential whereas HCOOH was not influenced by bicarbonate concentration. Our study provides insights into efficient, economically viable, and sustainable methods of mitigating the harmful environmental effects of CO2 emission.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1303-1308
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• 1999

Conducting poly(3,4-ethylenedioxythiophene) (PEDT) films with metalloporphyrins incorporated as the counter ions were prepared by electropolymerization of the monomer in the presence of metal-tetra(sulfonatophenyl) porphyrin anions. Cathodic reduction of oxygen on the resulting conducting polymer films was studied. The overpotential for O2 reduction on electrodes with cobalt-porphyrin complex was significantly smaller in acidic solutions than on gold. In basic solutions, the overpotential at low current densities was close to those on platinum and gold. Polymer electrode with Co-complex yielded higher limiting currents than with Fe-complex, although the Co-complex polymer electrode was a poorer electrocatalyst for O2 reduction in the activation range of potential than the Fe counterpart. From the rotating ring-disk electrode experiments, oxygen reduction was shown to proceed through either a 4-electron pathway or a 2-electron pathway. In contrast to the polypyr-role-based electrodes, the PEDT-based metalloporphyrin electrodes were stable with wider potential windows, including the oxygen reduction potential. Their electrocatalytic properties were maintained at temperatures up to 80℃ in KOH solutions.

• 청정기술
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• 제28권1호
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• pp.9-17
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• 2022

전기화학적 이산화탄소 환원 기술은 전기에너지를 이용하여 대표적인 온실가스인 이산화탄소를 유용한 기초 화학제품으로 전환시킬 수 있는 유망한 기술 중 하나다. 특히, 다양한 후보 제품 중 일산화탄소는 높은 Faraday 효율과 우수한 경제성을 나타내기 때문에 학계와 산업계의 많은 관심을 받고 있다. 과거 여러 연구진이 본 기술의 온실가스 저감 잠재량을 정량적으로 분석했으나, 분석 과정에서 도입된 과정과 사용된 인벤토리 데이터의 일관성 및 투명성에 문제가 제기된다. 본 연구에서는 전기화학적 이산화탄소 환원을 통한 일산화탄소 생산 공정의 온실가스 저감 잠재량 분석을 위한 전과정평가를 수행했다. 세 종류의 시스템 경계를 정의 후 각각의 지구온난화지수를 화석연료 기반 일산화탄소 생산 공정과 비교했다. 분석 결과, 전기화학적 일산화탄소 생산 기술을 도입하여 온실가스를 저감하기 위해서는 전해조 구동에 필요한 전기에너지의 배출계수가 현재 국내 발전부문의 배출계수보다 충분히 낮아야 한다는 점을 확인했다. 또한, 신뢰성 있는 온실가스 저감 잠재량 분석을 위해서는 기존의 화석연료 기반 일산화탄소 생산 공정의 인벤토리 정보를 투명하게 공개하는 것이 중요함을 밝혔다.