Model soot이 Pt/CeO₂ 촉매와 tight contact한 상태에서의 O₂에 의한 산화특성 연구

송창훈(Changhoon Song),이동일(Dongil Lee),김태수(Taesoo Kim),송순호(Soonho Song),전광민(Kwang Min Chun) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

The catalytic behaviors of Pt/CeO₂ have been studied for soot oxidation by O₂. Oxidation of soot (carbon black) is studied using a flow reactor system simulating the condition of diesel exhaust. In this study, the temperature programmed oxidation (TPO) scheme is used. And soot oxidation rate is evaluated by monitoring both CO and CO₂ concentrations. Pt/CeO₂ catalyst shows promising performance to accelerate the soot-O₂ reaction. Under tight contact condition with catalyst, soot oxidation reaction occurred more actively. The maximum soot oxidation temperature is decreased by about 150℃. The main reason that causes the increase of soot oxidation activity is the active oxygen from cerium oxide.

Analytical Study on Soot Formation in a Diesel Engine

Sangsu Lee,Nakwon Sung,Jeongmin Lee,Hongsuk Kim 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.1

The soot formation inside a diesel engine was studied by the analytical model. The soot is formed from gaseous carbon atoms by the phase change under the saturation condition. This soot model is implemented into the KIVA-3V code. From the results of the model, it is found that the fuel rich core of spray inside a flame is the main source of soot. The effect of injection timing is investigated by the soot model. When the injection timing is advanced, the formation of soot is suppressed because of high saturation pressure. The soot formation is increased when the injection timing is retarded mainly due to the decreased soot oxidation at low cylinder temperature.

Three-dimensional arrangements of perovskite-type oxide nano-fiber webs for effective soot oxidation

Lee, C.,Jeon, Y.,Hata, S.,Park, J.I.,Akiyoshi, R.,Saito, H.,Teraoka, Y.,Shul, Y.G.,Einaga, H. Elsevier 2016 Applied catalysis. B, Environmental Vol.191 No.-

<P>Perovskite-type oxides have been widely applied in heterogeneous catalytic reactions, such as soot oxidation. However, a poor contact point between the catalyst and solid reactant (soot) often limits the catalytic performance. Here, we report La1-xSrxCo0.2Fe0.8O3-delta perovskite oxide catalysts with a unique three-dimensional (3D) fiber web structure that increases the high-contact area by trapping soot in the unique pore structure for effective catalytic activity. This feature was carefully analyzed using scanning transmission electron microscopy (STEM) tomography to investigate the location of the soot on the web. The structure of the web, with a thickness of approximately 55 mu m, indicated that the soot particles were caught by the 3D pores between the fibers. The relationship between the Sr amount and activate oxygen was also characterized by means of XPS. The results show that the Sr amount of 0.4 produced the highest amount of active oxygen species (O-) that are essential for soot oxidation reaction. The developed catalyst exhibited a good catalytic performance due to the optimized perovskite chemical structure and the greatly increased number of the contact points owing to the 3D inter-fiber spaces. Hence, our proposed approach is reasonable for application to real soot combustion processes and can also be easily extended to numerous other catalytic processes to enhance the catalytic activity. (C) 2016 Elsevier B.V. All rights reserved.</P>

Pt/CeO₂ 촉매와 Tight Contact 한 상태의 Model Soot 산화에 NO가 미치는 영향에 관한 실험적 연구

이동일(Dongil Lee),송창훈(Changhoon Song),송순호(Soonho Song),전광민(Kwang Min Chun) 한국자동차공학회 2011 한국 자동차공학회논문집 Vol.19 No.3

Active regeneration in CDPF requires O₂ which regenerates soot at high temperature. However, small amount of NO can interrupt O₂ regeneration in CDPF. To verify this phenomena, soot oxidation experiments using a flow reactor with a Pt/CeO₂ catalyst are carried out to simulate Catalyzed Diesel Particulate Filter (CDPF) phenomena. Catalytic soot oxidation with and without small amount of NO is conducted under tight contact condition. As the heating rate rises, the temperature gap of maximum reaction rate is increased between with and without 50ppm NO. To accelerate the NO₂ de-coupling effect, CTO process is performed to eliminate interfacial contact for that time. As CTO process is extended, temperature which indicates peak reaction rate increases. From this result, it is found that small amount of NO can affect tight contact soot oxidation by removal of interfacial contact between soot and catalyst.

SIMULTANEOUSLY CATALYTIC REMOVAL OF NOx AND SOOT ON RARE EARTH ELEMENT OXIDE LOADED WITH POTASSIUM AND TRANSITION NANOSIZED METAL OXIDES

ZHI JIANG,HAIRONG ZHANG,ZHONGPENG WANG,MINGXIA CHEN,WENFENG SHANGGUAN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2008 NANO Vol.3 No.4

The simultaneous catalytic removal of NOx and soot over the rare earth element (REE) oxide-based mixture oxides loaded with potassium and transition nanosized metal oxide (designated as M/K/REE oxide) was investigated by using temperature-programmed reaction (TPR). The influence of the type of REE oxides together with the type and amount of transitional metal oxides on the catalytic removal activity was discussed. K/Nd2O3 was found to be the most active oxide among the REE oxides to simultaneous remove the NOx and soot under lean conditions. Chromium oxide was more active than the other transition metal oxides on enhancing the activity of soot oxidation of Nd2O3 loaded with potassium. The optimum loading level of chromium was about 10 wt%, with ignition temperature at about 237°C and the conversion ratio NO → N2 about 24.1%. The Mn-loading on K/Nd2O3 resulted in the biggest conversion efficiency of NO to N2 at about 30.2%. The increasing catalytic reaction of NOx–soot activities is attributed to the formation of complex crystalline phase in the catalyst together with the improving contacting between catalysts and soot.

Overview of the Effect of Catalyst Formulation and Exhaust Gas Compositions on Soot Oxidation In DPF

Choi Byung Chul,FOSTER D.E. The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.1

This work reviews the effects of catalyst formulation and exhaust gas composition on soot oxidation in CDPF (Catalytic Diesel Particulate Filter). DOC's (Diesel Oxidation Catalysts) have been loaded with Pt catalyst (Pt/$Al_{2}O_3$) for reduction of HC and CO. Recent CDPF's are coated with the Pt catalyst as well as additives like Mo, V, Ce, Co, Fe, La, Au, or Zr for the promotion of soot oxidation. Alkali (K, Na, Cs, Li) doping of metal catalyst tends to increase the activity of the catalysts in soot combustion. Effects of coexistence components are very important in the catalytic reaction of the soot. The soot oxidation rate of a few catalysts are improved by water vapor and NOx in the ambient. There are only a few reports available on the mechanism of the PM (particulate matter) oxidation on the catalysts. The mechanism of PM oxidation in the catalytic systems that meet new emission regulations of diesel engines has yet to be investigated. Future research will focus on catalysts that can not only oxidize PM at low temperature, but also reduce NOx, continuously self-cleaning diesel particulate filters, and selective catalysts for NOx reduction.

Ag-loaded cerium-zirconium solid solution oxide nano-fibrous webs and their catalytic activity for soot and CO oxidation

Lee, Chanmin,Jeon, Yukwon,Kim, Taehyen,Tou, Akihiro,Park, Joo-Il,Einaga, Hisahiro,Shul, Yong-Gun Elsevier 2018 Fuel Vol.212 No.-

<P><B>Abstract</B></P> <P>The catalytic combustion of soot and CO is one of the key technologies required to meet rigorous emission standards. Recently, solid solution materials have been employed in heterogeneous catalysts because of their remarkable intrinsic activities and good stabilities. However, the low number of contact points between soot particles and the catalyst remains a challenge to enhancing catalytic performance. Thus, we herein report the preparation of Ce-ZrO<SUB>2</SUB> solid solution nano-fibrous web catalysts with a hierarchical structure using an electrospinning method, where Ag particles were loaded onto the surface of the Ce-ZrO<SUB>2</SUB> webs. X-ray diffraction, scanning transmission electron microscopy, and energy dispersive spectroscopic studies allowed us to investigate the morphological and crystal structures of the prepared Ce-ZrO<SUB>2</SUB> and Ag/Ce-ZrO<SUB>2</SUB> web catalysts. Moreover, the relationship between the Ce/Zr ratio and activated oxygen is discussed based on X-ray photoelectron spectroscopy results. Following the catalytic oxidation of soot and CO using our novel materials, we found that the Ce<SUB>0.67</SUB>Zr<SUB>0.33</SUB>O<SUB>2</SUB> web exhibited higher catalytic activities than the Ce<SUB>0.5</SUB>Zr<SUB>0.5</SUB>O<SUB>2</SUB> and Ce<SUB>0.33</SUB>Zr<SUB>0.67</SUB>O<SUB>2</SUB> webs, respectively. In addition, Ag/Ce<SUB>0.67</SUB>Zr<SUB>0.33</SUB>O<SUB>2</SUB> exhibited enhanced catalytic activity compared with the pristine Ce<SUB>0.67</SUB>Zr<SUB>0.33</SUB>O<SUB>2</SUB> for the oxidation of both soot (e.g., 500°C vs. 544°C at 50% conversion) and CO (e.g., 282°C vs. 408°C at 50% conversion). It therefore appeared that our proposed Ce-ZrO<SUB>2</SUB> solid solution nano-fibrous web catalysts bearing Ag particles exhibited superior redox properties and enhanced surface areas, and as such, are promising candidates for use in the oxidation of both soot and CO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ce-ZrO<SUB>2</SUB> solid-solution oxide fibrous webs were synthesized by electrospinning. </LI> <LI> Ag particles were deposited to improve catalytic activity. </LI> <LI> Ag/Ce<SUB>0.67</SUB>Zr<SUB>0.33</SUB>O<SUB>2</SUB> exhibited superior catalytic activity to other sample. </LI> <LI> Redox property of Ag and enhanced surface areas improved the catalytic oxidation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ag 담지된 LaSrCoFeO₃ 섬유상 perovskite 촉매의 탄소 입자상 물질의 산화반응

이찬민,전유권,황호정,지윤성,권오찬,전옥성,설용건,Lee, Chanmin,Jeon, Yukwon,Hwang, Ho Jung,Ji, Yunseong,Kwon, Ohchan,Jeon, Ok Sung,Shul, Yong-Gun 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.4

디젤엔진 시스템은 미세먼지 배출의 엄격해진 저감/제어 기준을 충족하기 위해서 산화촉매는 매우 중요한 기술 중에 하나이다. 본 연구에서는 효율적인 soot산화의 촉매로 Ag 나노입자가 loading된 $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ 섬유상 web 촉매를 제시하였다. 제조된 촉매는 FE-SEM, EDS mapping, XRD, XPS 분석을 통해 특성을 평가하였다. Soot 산화성능측정결과 Ag의 효율적인 촉매특성과 증가된 soot입자와 표면의 접촉면적으로 인하여 50% 산화온도 평가($T_{50}=490^{\circ}C$)에서 자연적인 산화보다 $151^{\circ}C$ 가속화된 것을 확인하였다. 따라서 Ag가 loading된 촉매와 3차원적인 web 구조는 soot 산화에 효율적인 촉매후보군으로 확인하였다. The catalytic combustion of particulate matter (PM) is one of the key technologies to meet emission standards of diesel engine system. Therefore, we herein suggest Ag loaded $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ perovskite web catalyst. They were produced by the electrospinning method. FE-SEM, EDS mapping, XRD, XPS were studied to investigate the crystal and morphological structures of loaded Ag particles and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ perovskite web catalyst. Following the catalytic soot oxidation, we found that the Ag loaded $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ perovskiteweb catalyst showed the higher catalytic activities (e.g., $T_{50}=490^{\circ}C$) than the only $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ perovskite web catalyst (e.g., $T_{50}=586^{\circ}C$). Thus, this finding suggests that Ag loaded $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ perovskite web catalyst can be a promising candidate for enhancing the soot oxidation.

Preparation and catalytic activity of K4Zr5O12 for the oxidation of soot from vehicle engine emissions

Qiang Wanga,Ji Hyang Sohn,So Ye Park,Jin Seong Choi,Joo Young Lee,정종식 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.1

Pure phase K4Zr5O12 is synthesized via solid state method in the present work. Various K/Zr ratios and temperatures are applied, and the synthesis process is investigated in detail by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Its catalytic activity for soot oxidation is studied by temperature programmed oxidation with different types of soot/catalyst contacts. It is revealed that K4Zr5O12 is very active in the presence of 2–10% O2 for both tight and loose contacts (Tp(tight) = 335 oC, Tp(ethanol) = 355 oC and Tp(shaking) = 370 oC). Thermal stability study shows that K4Zr5O12 is highly stable up to at least 900 oC.

Transition metal modified manganese-based catalysts for soot oxidation promoted by noncompetitive adsorption of oxygen: Experiments and DFT calculations

Congcong Li,Ruiqi Li,Yuhang Wang,Runhan Niu,Qilong Guo,Changsen Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

A series of manganese-based oxide catalysts were synthesized by the hydrothermal method. By adjustingthe doping amounts of W and Cu in the system to study the catalytic performance of transition metaldopedmanganese oxides on soot combustion. They were deeply studied through various characterizationsand theoretical calculations. The results show that Wand Cu doping modifications can significantlyimprove the activity of manganese-based oxides in soot oxidation. W-Cu0.1/MnOx prepared by comodificationofWand Cu at 395 C can convert 90% of soot into CO2. The multiple characterization resultsshow that by adjusting the doping amount of copper and tungsten, the nano-flower-like morphology canbe obtained and the crystal plane can be reconstructed, which is helpful to increase the specific surfacearea, Mn3+ content, and oxygen vacancy content. The theoretical calculation results show that the oxygenvacancy on the surface of the catalyst shows the ability to activate O2 and H2O, and they show noncompetitiveadsorption. In addition, W-Cu0.1/MnOx has a good application prospect in the catalytic oxidationof soot because of its excellent catalytic stability. This work provides a reference for the designand preparation of non-noble metal-based catalysts for the elimination of soot particles from dieselengine exhaust.