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Characterizations of organic compounds in diesel exhaust particulates

Journal of Environmental Sciences 2015年第8期27卷 171-183页

作者： jaehyun lim Cheolsoo lim Sangkyun Kim Jihyung Hong Division of Global Environment Research National Institute of Environmental Research Department of Climate and Air Quality Research National Institute of Environmental Research

To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter（PM） below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine（34–94 nm） and accumulation（94–1000 nm） modes ranged from 2.9 to 5.7 μg/m3 and 9.5 to 16.4 μg/m3, respectively. As a function of driving conditions, the non-oxygencontaining organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes： alkanes,alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers,nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions,alkane class consistently showed the highest concentration（8.3 to 18.0 μg/m3） followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons（PAHs）were identified with a total concentration ranging from 37.9 to 174.8 ng/m3. In addition, nine nitrogen-containing polycyclic aromatic compounds（NPACs） were identified with a total concentration ranging from 7.0 to 10.3 ng/m3. The most abundant PAH（phenanthrene）and NPACs（7,8-benzoquinoline and 3-nitrophenanthrene） comprise a similar molecular（3 aromatic-ring） structure under the highest engine speed and engine load.

关键词： Diesel particle matter Organic compounds Polycyclic aromatic hydrocarbons Nitrogen-containing polycyclic aromatic compounds

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Characterization of particulate matter from diesel passenger cars tested on chassis dynamometers

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Journal of Environmental Sciences 2017年第4期29卷 21-32页

作者： Sungwoon Jung jaehyun lim Sangil Kwon Sangwoo Jeon Jeongsoo Kim Jongtae Lee Sunmoon Kim Transportation Pollution Research Center National Institute of Environmental Research Incheon Republic of Korea Division of Global Environment Research National Institute of Environmental Research Incheon Republic of Korea Compliance & Defects Investigation Office Korea Automobile Testing & Research Institute Hwasung Republic of Korea

Emission characterization of particle number as well as particle mass from three diesel passenger cars equipped with diesel particulate filter（DPF）, diesel oxidation catalyst（DOC）and exhaust gas recirculation（EGR） under the vehicle driving cycles and regulatory *** particle number emissions（PNEs） decreased gradually during speed-up of vehicle from 17.3 to 97.3 km/hr. As the average vehicle speed increases, the size-segregated peak of particle number concentration shifts to smaller size ranges of particles. The correlation analysis with various particulate components such as particle number concentration（PNC）,ultrafine particle number concentration（UFPNC） and particulate matter（PM） mass was conducted to compare gaseous compounds（CO, CO2, HC and NOx）. The UFPNC and PM were not only emitted highly in Seoul during severe traffic jam conditions, but also have good correlation with hydrocarbons and NOxinfluencing high potential on secondary aerosol generation. The effect of the dilution temperature on total PNC under the New European Driving Cycle（NEDC）, was slightly higher than the dilution ratio. In addition, the nuclei mode（DP： ≤ 13 nm） was confirmed to be more sensitive to the dilution temperature rather than other particle size ranges. Comparison with particle composition between vehicle speed cycles and regulatory cycle showed that sulfate was slightly increased at regulatory cycle, while other components were relatively similar. During cold start test, semivolatile nucleation particles were increased due to effect of cold environment. Research on particle formation dependent on dilution conditions of diesel passenger cars under the NEDC is important to verify impact on vehicular traffic and secondary aerosol formation in Seoul.

关键词： Diesel passenger cars Particle number emissions Correlation analysis Particle number concentration Ultrafine particle number concentration

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Crystallographically vacancy-induced MOF nanosheet as rational single-atom support for accelerating CO2 electroreduction to CO

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CARBON ENERGY 2024年第8期6卷 49-62页

作者： Cho, Jin Hyuk Ma, Joonhee Lee, Chaehyeon lim, Jin Wook Kim, Youngho Jang, Ho Yeon Kim, jaehyun Seo, Myung-gi Choi, Youngheon Jang, Youn Jeong Ahn, Sang Hyun Jang, Ho Won Back, Seoin Lee, Jong-Lam Kim, Soo Young Korea Univ Dept Mat Sci & Engn Seoul South Korea Korea Univ Dept Mat Sci & Engn Seoul 02841 South Korea Sogang Univ Dept Chem & Biomol Engn Seoul South Korea Sogang Univ Inst Emergent Mat Dept Chem & Biomol Engn Seoul 04107 South Korea Pohang Univ Sci & Technol POSTECH Dept Mat Sci & Engn Pohang South Korea Pohang Univ Sci & Technol POSTECH Dept Mat Sci & Engn Pohang 790784 South Korea Seoul Natl Univ Res Inst Adv Mat Dept Mat Sci & Engn Seoul South Korea Lotte Chem R&D Ctr Daejeon South Korea Hanyang Univ Dept Chem Engn Seoul South Korea Chung Ang Univ Sch Chem Engn & Mat Sci Seoul South Korea

To attain a circular carbon economy and resolve CO2 electroreduction technology obstacles, single-atom catalysts (SACs) have emerged as a logical option for electrocatalysis because of their extraordinary catalytic activity. Among SACs, metal-organic frameworks (MOFs) have been recognized as promising support materials because of their exceptional ability to prevent metal aggregation. This study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100% for CO formation in H-cell and three-compartment microfluidic flow-cell reactors and an excellent turnover frequency of 23,699 h(-1), validating their intrinsic catalytic potential. These results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets, which are linked to the evaporation of Zn-containing organic linkers during pyrolysis. Furthermore, using X-ray absorption spectroscopy and density functional theory calculations, a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO* preadsorbed sites as initial states was possible and provided valuable insights.

关键词： 2-dimensional material carbon dioxide reduction metal-organic frameworks single-atom catalysts vacancy sites ACTIVE-SITES CATALYSTS EVOLUTION REDUCTION ZIF-8

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