催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (12): 1965-1973.DOI: 10.3724/SP.J.1088.2012.20746

• 研究论文 • 上一篇    下一篇

MnOx 负载量对 MnOx/Ce0.7Zr0.2La0.1O2-Al2O3 催化剂上碳烟燃烧性能的影响

朱艺1, 潘浩2, 陈山虎2, 王世丹2, 赵明2, 龚茂初2, 陈耀强2,*   

  1. 1四川大学建筑与环境学院, 四川成都 610065; 2四川大学化学学院, 绿色化学与技术教育部重点实验室, 四川成都 610064
  • 收稿日期:2012-07-30 修回日期:2012-09-06 出版日期:2013-01-18 发布日期:2012-12-18

Influence of MnOx Loading on Activity of MnOx/Ce0.7Zr0.2La0.1O2-Al2O3 Catalyst for Catalytic Combustion of Diesel Soot

ZHU Yi1, PAN Hao2, CHEN Shanhu2, WANG Shidan2, ZHAO Ming2, GONG Maochu2, CHEN Yaoqiang2,*   

  1. 1College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan, China; 2Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China
  • Received:2012-07-30 Revised:2012-09-06 Online:2013-01-18 Published:2012-12-18

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摘要： 采用等体积浸渍法制备了一系列不同 MnOx 含量的 MnOx/Ce0.7Zr0.2La0.1O2-Al2O3 (Ce0.7Zr0.2La0.1O2 /Al2O3 质量比 = 1) 催化剂, 并用 X 射线衍射、低温 N2 吸附-脱附、X 射线光电子能谱、O2 程序升温脱附和 H2 程序升温还原等手段对催化剂进行了表征, 考察了催化剂催化柴油车排放碳烟颗粒物燃烧的反应性能. 结果表明, 催化剂表面吸附的活性氧物种和 MnOx 的低温区还原性能是决定催化剂活性的两大关键因素. 当 MnOx 负载量为 5% 时, 催化反应所需的活性氧减少, 因而活性降低; 但 MnOx 负载量增至 10% 时, 催化剂中 Mn 物种的可还原量提高, 从而增加其活性; 增至 20% 时, MnOx 与表面吸附氧物种的可还原量间达平衡最佳值, 活性最佳, 碳烟起燃温度比无催化剂时降低了 179 oC; 负载量达 30% 后, 由于载体表面吸附氧物种数量的降低和还原峰温的上升使催化剂活性下降.

关键词: 锰氧化物, 负载量, 碳烟, 催化燃烧, 氧化铈, 氧化锆, 氧化镧, 氧化铝

Abstract: A series of MnOx/Ce0.7Zr0.2La0.1O2-Al2O3 supported catalysts with the Ce0.7Zr0.2La0.1O2:Al2O3 mass ratio of 1:1 and different MnOx loadings were prepared by the incipient wetness method. The catalysts were characterized by X-ray diffraction, low temperature N2 adsorption-desorption, X-ray photoelectron spectroscopy, O2 temperature-programmed desorption, and H2 temperature-programmed reduction. The catalytic performance of these catalysts for the combustion of diesel soot was investigated. It is found that surface-adsorbed active oxygen species and low-temperature reducibility of MnOx are the determinants of catalytic activity. When the MnOx loading is 5%, the catalyst activity decreases owing to the loss of active oxygen species, which are necessary for the catalytic combustion. When the MnOx loading is increased to 10%, the catalyst activity is dramatically increased because of the enhanced reducible manganese species. Interestingly, the optimal values for reducible manganese species and surface-adsorbed oxygen species can be achieved in the catalyst with 20% MnOx, and so the catalyst exhibits the best catalytic activity, giving a light-off temperature about 179 oC lower than that of the non-catalytic soot combustion. With a further addition of MnOx species up to 30%, its catalytic activity is deteriorated mainly due to the decrease in surface-trapped oxygen species and upper shift of the reduction temperature.

Key words: manganese oxide, loading amount, soot, catalytic combustion, ceria, zirconia, lanthana, alumina