| 荧光XAFS表征Pt/BaAl2O4-Al2O3催化剂中的微量铂物种 |
| Fluorescence-XAFS Characterization on the Small Amount of Platinum in Pt/BaAl2O4-Al2O3 Catalysts |
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| 摘要: |
| 关键词: Pt/BaAl2O4-Al2O3催化剂 氮氧化物储存 XAFS |
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| Abstract: The support BaAl2O4-Al2O3 and the catalysts Pt/BaAl2O4-Al2O3 were prepared by co-precipitation and impregnation method, respectively. The NOx storage capacities (NSC) of the samples were investigated. The fluorescence-XAFS technique was employed to characterize the fine structures of the small amount of platinum. The results show that after calcination in air, the platinum mainly exists as chloride, and the rest is in the form of oxychloride, however, after reduction by H2, the most platinum species transform into highly dispersed metallic crystallite (2~3 nm) with a very small residual amount of chloride. After aging treatment, a small part of platinum in the reduced sample is oxidized into oxide. Combined with the results of the NOx storage capacities, it is indicated that for NOx storage, highly dispersed metallic platinum crystallites are the most active phase, while the chloride species of platinum have much weaker effect on NOx storage. The growth of Pt crystallite size and the partial oxidation of metallic Pt are the main reasons for the decrease of NOx storage capacity of the aged sample. |
| Keywords: Pt/BaAl2O4-Al2O3 catalyst NOx storage XAFS |
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| 摘要点击次数: 1682 |
| 全文下载次数: 1970 |
| 孟明,张忠和,罗金勇,林培琰,伏义路.荧光XAFS表征Pt/BaAl2O4-Al2O3催化剂中的微量铂物种[J].无机化学学报,2006,22(2):298-302. |
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