The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Guan Naijia - One of the best experts on this subject based on the ideXlab platform.
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Metal-ZSM-5/Cordierite Monolithic Catalysts for Purifying Lean-Burn Engine Exhaust
Chinese Journal of Catalysis, 2006Co-Authors: Guan NaijiaAbstract:By in situ synthesis, the ZSM-5 zeolite grew on the cordierite substrate and formed ZSM-5/cordierite monolith. Metal (Cu, In or Ag)-modified ZSM-5/cordierites were studied as catalysts to treat the exhaust of lean-Burn Engine. Cu-ZSM-5/cordierite exhibited the best catalytic performance, and three main pollutants NO_x, CO and HC in the exhaust could be purified simultaneously. By further modification with a trace amount (0.02%) a noble metal (Pd, Rh or Ir), the purification ability of the catalysts for CO was greatly enhanced, and the temperature window of high NO_x conversion was greatly broadened. Bimetal modified ZSM-5/cordierites were then regarded as promising catalysts in purifying the lean-Burn exhaust. The modification effect of the trace noble metal on the catalytic performance of Cu-ZSM-5/cordierite was also discussed.
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Selective Catalytic Reduction of Nitrogen Oxides from Exhaust of Lean Burn Engine over In-Situ Synthesized Cu-ZSM-5/Cordierite
Environmental science & technology, 2005Co-Authors: Li Landong, Chen Jixin, Zhang Shu-juan, Zhang Fuxiang, Guan Naijia, Wang Tianyou, Liu ShuliangAbstract:ZSM-5 zeolite was in-situ synthesized successfully on the surface of honeycomb cordierite substrate, certified by XRD and SEM techniques. Good thermal and hydrothermal stability of ZSM-5/cordierite could be obtained because of the in-situ synthesis method. Copper ion-exchanged ZSM-5/cordierite was studied as catalyst for selective catalytic reduction of nitrogen oxides. For practical reasons, the catalytic testing experiments were preformed on a real lean Burn Engine. UnBurned hydrocarbons and carbon monoxide in the exhaust were directly used as reductants for NOx reduction. Cu-ZSM-5/cordierite exhibited high catalytic activity, and at 673 K the maximal NOx conversion to N2 could reach 50% at gas hourly space velocity (GHSV) of about 25 000 h(-1). Hydrocarbons and carbon monoxide in the exhaust could also be purified at the same time. As expected, Cu-ZSM-5/cordierite catalyst exhibited good duration and antipoison properties. When traces of lanthanum were introduced to Cu-ZSM-5/cordierite catalyst as a modifier, the activated temperature of the catalyst could be decreased and the temperature window with high NOx conversions broadened. Cu-ZSM-5/ cordierite and LaCu-ZSM-5/cordierite were thought as promising automobile exhaust catalysts under lean conditions. Copper is the main active component in the Cu-ZSM-5/ cordierite catalyst and Cu(II), which was found in the catalyst during the proceeding of reaction by XPS, is thought to be essential. On the basis of this, deNOx process over Cu-ZSM-5/cordierite is also discussed.
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Selective Catalytic Reduction of Nitrogen Oxides from Exhaust of Lean Burn Engine over In-Situ Synthesized Cu-ZSM-5/Cordierite
Environmental science & technology, 2005Co-Authors: Li Landong, Chen Jixin, Zhang Shu-juan, Zhang Fuxiang, Guan Naijia, Wang Tianyou, Liu ShuliangAbstract:ZSM-5 zeolite was in-situ synthesized successfully on the surface of honeycomb cordierite substrate, certified by XRD and SEM techniques. Good thermal and hydrothermal stability of ZSM-5/cordierite could be obtained because of the in-situ synthesis method. Copper ion-exchanged ZSM-5/cordierite was studied as catalyst for selective catalytic reduction of nitrogen oxides. For practical reasons, the catalytic testing experiments were preformed on a real lean Burn Engine. UnBurned hydrocarbons and carbon monoxide in the exhaust were directly used as reductants for NOx reduction. Cu−ZSM-5/cordierite exhibited high catalytic activity, and at 673 K the maximal NOx conversion to N2 could reach 50% at gas hourly space velocity (GHSV) of about 25 000 h-1. Hydrocarbons and carbon monoxide in the exhaust could also be purified at the same time. As expected, Cu−ZSM-5/cordierite catalyst exhibited good duration and antipoison properties. When traces of lanthanum were introduced to Cu−ZSM-5/cordierite catalyst as a modi...
Tianyou Wang - One of the best experts on this subject based on the ideXlab platform.
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Combination catalyst for the purification of automobile exhaust from lean-Burn Engine
Fuel Processing Technology, 2013Co-Authors: Tianyou Wang, Naijia GuanAbstract:Abstract LaCu-ZSM-5/cordierite and Ir/ZSM-5/cordierite were prepared and studied as possible catalysts for the selective reduction of nitrogen oxides in excess oxygen. LaCu-ZSM-5/cordierite exhibited good activity in C 3 H 6 -SCR reaction and a maximal nitrogen oxide conversion of ca. 80% could be obtained at 623 K under reaction conditions employed. The existence of carbon monoxide in the reaction system showed positive effects on C 3 H 6 -SCR over LaCu-ZSM-5/cordierite. Ir/ZSM-5/cordierite exhibited good activity in CO-SCR reaction and a maximal NO x conversion of ca. 55% could be obtained at 523 K. The existence of C 3 H 6 showed negative effects on CO–SCR over Ir/ZSM-5/cordierite at relatively low temperatures. Based on the catalytic results, combination catalyst LaCu-ZSM-5/cordierite and Ir/ZSM-5/cordierite were developed for the reduction of nitrogen oxides from real lean-Burn automobile exhaust by utilizing hydrocarbons and carbon monoxide as reducing agents. With contributions from both C 3 H 6 -SCR and CO–SCR, the major pollutants in lean-Burn automobile exhaust, e.g. nitrogen oxides, unBurned hydrocarbons and carbon monoxide, could be purified simultaneously.
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Preparation of Pt/beta zeolite–Al2O3/cordierite monolith for automobile exhaust purification
Ceramics International, 2011Co-Authors: Tianyou Wang, Shenghua Yang, Kai Sun, Xuefei FangAbstract:Abstract A two-step route was developed to prepare zeolite beta coatings on structured monolith. Al 2 O 3 layer was deposited on cordierite substrate by slurry dip-coating in the first step and beta zeolite layer was then coated on Al 2 O 3 /cordierite by direct dynamic hydrothermal synthesis in the second step. The as-prepared beta zeolite–Al 2 O 3 /cordierite was characterized by means of XRD and SEM techniques and the stability of beta coatings was studied. Based on these results, the advantages of the two-step method were discussed. After the introduction of Pt to beta zeolite–Al 2 O 3 /cordierite, the obtained Pt/beta zeolite–Al 2 O 3 /cordierite monolith was tested as promising catalyst for the purification of automobile exhaust from real lean-Burn Engine.
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Selective catalytic reduction of nitrogen oxides from exhaust of lean Burn Engine over in situ synthesized monolithic Cu–TS-1/cordierite
Catalysis Today, 2004Co-Authors: Jixin Chen, Shujuan Zhang, Naijia Guan, Tianyou Wang, Shuliang LiuAbstract:Abstract Titanium silicalite (TS-1) zeolite was in situ synthesized successfully on the surface of honeycomb cordierite substrate, which was certified by XRD and SEM techniques. The in situ synthesized monolithic TS-1/cordierite showed superior thermal and hydrothermal stabilities. Cu–TS-1/cordierite prepared with ion-exchange and impregnation methods were studied as catalysts for selective catalytic reduction (SCR) of nitrogen oxides (NOx). For practicality, the evaluation experiments were carried out in exhaust of a real lean Burn Engine without any other additive. Cu–TS-1/cordierite prepared with two methods both exhibited similar high activities, and at about 715 K, the max NOx conversion could reach 58% in the space velocity (SV) of 12000 h−1. Ion-exchanged Cu–TS-1/cordierite had superior duration and anti-poison properties while impregnated Cu–TS-1/cordierite not. Cooper is the main active component in the catalyst and Cu(I), which was found in the catalyst during the proceeding of reaction by XPS, is thought to be essential.
Naijia Guan - One of the best experts on this subject based on the ideXlab platform.
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Combination catalyst for the purification of automobile exhaust from lean-Burn Engine
Fuel Processing Technology, 2013Co-Authors: Tianyou Wang, Naijia GuanAbstract:Abstract LaCu-ZSM-5/cordierite and Ir/ZSM-5/cordierite were prepared and studied as possible catalysts for the selective reduction of nitrogen oxides in excess oxygen. LaCu-ZSM-5/cordierite exhibited good activity in C 3 H 6 -SCR reaction and a maximal nitrogen oxide conversion of ca. 80% could be obtained at 623 K under reaction conditions employed. The existence of carbon monoxide in the reaction system showed positive effects on C 3 H 6 -SCR over LaCu-ZSM-5/cordierite. Ir/ZSM-5/cordierite exhibited good activity in CO-SCR reaction and a maximal NO x conversion of ca. 55% could be obtained at 523 K. The existence of C 3 H 6 showed negative effects on CO–SCR over Ir/ZSM-5/cordierite at relatively low temperatures. Based on the catalytic results, combination catalyst LaCu-ZSM-5/cordierite and Ir/ZSM-5/cordierite were developed for the reduction of nitrogen oxides from real lean-Burn automobile exhaust by utilizing hydrocarbons and carbon monoxide as reducing agents. With contributions from both C 3 H 6 -SCR and CO–SCR, the major pollutants in lean-Burn automobile exhaust, e.g. nitrogen oxides, unBurned hydrocarbons and carbon monoxide, could be purified simultaneously.
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Selective catalytic reduction of nitrogen oxides from exhaust of lean Burn Engine over in situ synthesized monolithic Cu–TS-1/cordierite
Catalysis Today, 2004Co-Authors: Jixin Chen, Shujuan Zhang, Naijia Guan, Tianyou Wang, Shuliang LiuAbstract:Abstract Titanium silicalite (TS-1) zeolite was in situ synthesized successfully on the surface of honeycomb cordierite substrate, which was certified by XRD and SEM techniques. The in situ synthesized monolithic TS-1/cordierite showed superior thermal and hydrothermal stabilities. Cu–TS-1/cordierite prepared with ion-exchange and impregnation methods were studied as catalysts for selective catalytic reduction (SCR) of nitrogen oxides (NOx). For practicality, the evaluation experiments were carried out in exhaust of a real lean Burn Engine without any other additive. Cu–TS-1/cordierite prepared with two methods both exhibited similar high activities, and at about 715 K, the max NOx conversion could reach 58% in the space velocity (SV) of 12000 h−1. Ion-exchanged Cu–TS-1/cordierite had superior duration and anti-poison properties while impregnated Cu–TS-1/cordierite not. Cooper is the main active component in the catalyst and Cu(I), which was found in the catalyst during the proceeding of reaction by XPS, is thought to be essential.
Shinichi Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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denox catalyst for automotive lean Burn Engine
Catalysis Today, 1996Co-Authors: Shinichi MatsumotoAbstract:Abstract The performance and durability of Cu-ZSM-5 were studied. Cu-ZSM-5 has fairly high NOx reduction activity but its durability is insufficient for practical use. We developed a new deNOx catalyst. In this catalyst, we call NOx storage reduction catalyst (NSR-catalyst), NOx emitted from an Engine at lean A F operation is stored and this stored NOx is reduced at stoichiometric or rich operation. This catalyst has been used on the Toyota CARINA with a lean-Burn Engine in Japan since 1994. This report outlines the results of our study on Cu-ZSM-5 and NSR-catalyst.
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The new concept 3-way catalyst for automotive lean-Burn Engine: NOx storage and reduction catalyst
Catalysis Today, 1996Co-Authors: Naoki Takahashi, Shinichi Matsumoto, Hirofumi Shinjoh, Tomoko Iijima, Tadashi Suzuki, Kiyoshi Yamazaki, Koji Yokota, Hiromasa Suzuki, Naoto Miyoshi, Tsuneyuki TanizawaAbstract:The new concept 3-way catalysts for a lean-Burn Engine have been developed, and their NOx purification mechanisms have been studied. The catalysts consist of precious metals, aluminum oxide and some other metal compounds such as NOx, storage compounds. NOx is oxidized over the precious metals and stored as nitrate ion combined with NOx storage compounds under oxidizing conditions. The stored NOx, is reduced to N2 under stoichiometric and reducing conditions. The NOx, storage capacity is deteriorated by sulfur. The improved catalysts showed sufficient NOx, conversion durability in the Japanese 10–15 mode test.
Elisabeth Siebert - One of the best experts on this subject based on the ideXlab platform.
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Coupling catalysis to electrochemistry: a solution to selective reduction of nitrogen oxides in lean-Burn Engine exhausts?
Journal of Catalysis, 2003Co-Authors: Philippe Vernoux, François Gaillard, C. Lopez, Elisabeth SiebertAbstract:The non-faradaic electrochemical modification of catalytic activity (NEMCA) was investigated in selective catalytic reduction (SCR) of NO by propene on Pt films deposited on NASICON, a Na+ conducting solid electrolyte. This study was carried out under lean-Burn conditions. In such a system, electrochemical promotion is shown to strongly enhance both the catalytic activity and the selectivity to N2. Such an improvement can be obtained using low overpotentials, applying −100 mV to the Pt catalyst-electrode enhances the selectivity to N2 from 41 to 61%. The use of NASICON allows work to be done at quite low temperatures (about 300 °C) compatible with the treatment of automotive exhausts.
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Coupling catalysis to electrochemistry: a solution to selective reduction of nitrogen oxides in lean-Burn Engine exhausts?
Journal of Catalysis, 2003Co-Authors: Philippe Vernoux, François Gaillard, C. Lopez, Elisabeth SiebertAbstract:International audienceThe non-faradaic electrochemical modification of catalytic activity (NEMCA) was investigated in selective catalytic reduction (SCR) of NO by propene on Pt films deposited on NASICON, a Na+ conducting solid electrolyte. This study was carried out under lean-Burn conditions. In such a system, electrochemical promotion is shown to strongly enhance both the catalytic activity and the selectivity to N2. Such an improvement can be obtained using low overpotentials, applying −100 mV to the Pt catalyst-electrode enhances the selectivity to N2 from 41 to 61%. The use of NASICON allows work to be done at quite low temperatures (about 300 °C) compatible with the treatment of automotive exhausts
