催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (7): 781-787.

• 研究论文 • 上一篇    下一篇

Rh-Au/γ-Al2O3 三效纳米催化剂的制备与表征

刘立成1, 訾学红1, 戴洪兴1, 赵震2, 王新平3, 何洪1   

  1. 1北京工业大学环境与能源工程学院化学化工系, 北京 100124 2中国石油大学 (北京) 重质油国家重点实验室, 北京 1022493大连理工大学精细化工国家重点实验室, 辽宁大连 116024
  • 收稿日期:2010-07-25 出版日期:2010-07-25 发布日期:2010-07-25

Preparation and Characterization of Rh-Au/冏-Al2O3 Three-Way Nanocatalysts

LIU Licheng1, ZI Xuehong1, DAI Hongxing1, ZHAO Zhen2, WANG Xinping3, HE Hong1,*   

  1. 1College of Environmental and Energy Engineering, Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing 100124, China 2State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China 3State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2010-07-25 Online:2010-07-25 Published:2010-07-25

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摘要：

采用超声辅助膜扩散还原法 (UAMR) 和等体积浸渍法 (IMP) 制备了 Rh/γ-Al2O3 和 Rh-Au/γ-Al2O3 催化剂, 考察了它们的三效模型反应 (CO+O2, C3H8+O2, CO+NO 和 C3H6+NO+O2) 活性. H2-O2 滴定和透射电镜结果表明, UAMR 法制得的 Rh/γ-Al2O3 和 Rh-Au/γ-Al2O3 催化剂的金属分散度分别为 45.3% 和 40.1%, 金属粒子表面积分别为 199.6 和 133.0 m2/g, 金属粒子平均粒径小于 3 nm. 对于三效模型反应, 与 IMP 法制备的催化剂相比, UAMR 法制备的 Rh/γ-Al2O3 和 Rh-Au/γ-Al2O3 具有更高的初始活性, 其中后者的活性也高于或接近于 IMP 法制备的 Rh/γ-Al2O3 催化剂. 催化剂经高温老化处理后, 活性均有所下降. UAMR 是一种新颖的负载型纳米催化剂的制备方法, 具有潜在的应用前景.

关键词: 三效催化剂, 铑, 金, 氧化铝, 膜扩散还原, 浸渍法

Abstract:

Rh/-Al2O3 and Rh-Au/-Al2O3 catalysts were prepared by the ultrasound-assisted membrane reduction (UAMR) and the incipient wetness impregnation (IMP) methods. The properties of the catalysts for three-way catalytic model reactions (CO and C3H8 oxidation, CO + NO, and C3H6+NO+O2) were investigated. The catalysts were characterized by inductively coupled plasma-optical emission spectrometry, H2-O2 titration, N2 adsorption, and transmission electron microscopy. The metal dispersion of the Rh/-Al2O3-UAMR and Rh-Au/ -Al2O3-UAMR catalysts was 45.3% and 40.1% with the metallic surface area of 199.6 and 133.0 m2/g, respectively, and the average metal particle size was smaller than 3 nm. Compared with Rh/-Al2O3-IMP and Rh-Au/-Al2O3-IMP, the Rh/-Al2O3-UAMR and RhAu/-Al2O3- UAMR catalysts possessed much higher catalytic activity for the model reactions. However, the activity of the Rh-Au/-Al2O3- UAMR catalyst was higher than or similar to that of the Rh/-Al2O3-IMP for the model reactions, indicating that the UAMR is a promising method for fabrication of three-way catalysts. The catalysts were deactivated to some extent by hydrothermal pretreatment at 1 000 oC.

Key words: three-way catalyst, rhodium, gold, alumina, membrane reduction, impregnation