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李新刚, X. Li, F. Gaillard, P. Vernonx
Ionics 11 (2005),-0001,():
-1年11月30日
This study deals with the relationship between open-circuit potential and catalytic activity of the system Pt/YSZ. Temperature-programmed desorption (TPD) of oxygen was carried out in order to investigate the link between the oxygen coverage and the potential. Then, catalytic activity in parallel with the potential value was measured between 200℃ and 500℃ for NO oxidation, C3H8 combustion, C3H6 combustion and the selective catalytic reduction (SCR) of NO by C3H6 in the presence of oxygen. It was found that potential measurement can give precious information on the competitive adsorption between oxygen and other reactants. Finally, it seems to be also a good way to anticipate the NEMCA behavior for reactions, which involve oxygen.
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【期刊论文】THE STUDY OF THE RELATIONSHIP BETWEEN MICROSTRUCTURE AND PERFORMANCE FOR NOx STORAGE CATALYSTS
李新刚, X. LI, M. MENG, P. LIN, Y. FU, T. HU, Y. XIE, J. ZHANG
Trans IChemE, Vol 80, Part A, March 2002,-0001,():
-1年11月30日
Aseries of Pt/BaAl2O4-Al2O3 NOx storage catalysts were prepared using the coprecipitation-impregnation method. XRD, XANES and EXAFS were used to characterize the microstructure of barium and platinum species in the samples. Barium exists in the forms of BaAl2O4 and BaCO3 crystallites. With the decreasing of calcination-temperature and barium content, the dispersion of BaAl2O4 phases becomes higher in the samples. In comparison with platinum standard compounds, the magnitude of the Pt-Pt coordination is significantly decreased, and the coordination distance is also shortened by about 0.01 nm. Platinum mainly exists as small atomic clusters, which possess a high dispersion, while some Pt (+4) species still present in the samples. A high dispersion of platinum and barium can greatly enhance the catalyst to store NOx.
NOx, Pt/, BaAl2O4-Al2O3, Storage, EXAFS, XANES.,
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李新刚
,-0001,():
-1年11月30日
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【期刊论文】A study on the properties and mechanisms for NOx storage over Pt/BaAl2O4–Al2O3 catalyst
李新刚, Xingang Li, Ming Meng, Peiyan Lin, Yilu Fu, Tiandou Hu, Yaning Xie, Jing Zhang
Topics in Catalysis Vol. 22, Nos. 1/2, January 2003,-0001,():
-1年11月30日
The NOx storage catalyst Pt/BaAl2O4–Al2O3 was prepared by a coprecipitation–impregnation method. For fresh sample, the barium mainly exists as the BaAl2O4 phase except for some BaCO3 phase. The BaAl2O4 phase is the primary NOx storage phase of the sample. EXAFS and TPD were used for investigating the mechanism of NOx storage. It is found that two kinds of Pt sites are likely to operate. Site 1 is responsible for NO chemisorption and site 2 for oxidizing NO to nitrates and nitrites. When NO adsorbs on the sample below 200℃, it mainly chemisorbs in the form of molecular states. Such adsorption results in an increase of the coordination magnitude of Pt–O, and a decrease of that of Pt–Pt and Pt–Cl. The coordination distance of Pt–Pt, Pt–Cl and Pt–O also increases. When the adsorption occurs above 200℃, NO can be easily oxidized by O2, and stored as nitrites or nitrates at the basic BaAl2O4. Site 2 is regenerated quickly. A high adsorption temperature is favorable for nitrate formation.
Pt/, BaAl2O4–Al2O3, NOx, storage,, EXAFS, TPD, mechanism
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李新刚, Jin-Yong Luo, Ming Meng, XiangLi, Xin-Gang Li, Yu-Qing Zha, Tian-Dou Hu, Ya-Ning Xie, Jing Zhang
Journal of Catalysis 254 (2008) 310–324,-0001,():
-1年11月30日
Several nanosized catalysts Co3O4–CeO2 with varying compositions were synthesized by a surfactant-template method and further promoted by a small amount of Pd (0.5 wt%). These catalysts exhibit uniform mesoporous structure and high surface area (>100 m2 g−1). The Co3O4 crystallites in these catalysts are encapsulated by nanosized CeO2 with only a small fraction of Co ions exposing on the surface and strongly inter- acting with CeO2. Such structure maximizes the interaction between Co3O4 and CeO2 in three dimensions, resulting in unique redox properties. The introduction of Pd prominently enhances both the reduction and oxidation performance of the catalysts, due to hydrogen or oxygen spillover. These catalysts prepared by surfactant-template method exhibit excellent oxidation performance, especially the ones promoted with Pd, which show markedly enhanced CO oxidation activity even at room temperature. Based upon the results of structural properties, redox behaviors and in situ DRIFTS study, two different reaction pathways over Co3O4–CeO2 and Pd/Co3O4–CeO2 are proposed.
Cobalt oxide, Ceria, Palladium, Mesoporous catalyst, CO oxidation, Structural characterization, Synergy, Mechanism.,
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