Au/Al2O3/Mn2O3催化剂的低温NOx储存还原性能

摘要

采用球磨法制取了Au/Al₂O₃/Mn₂O₃催化剂,并对其进行了NO_x储存还原(NSR)性能研究。实验结果表明,Au担载量对该催化剂的低温NSR催化活性有很大的影响,随着Au担载量的增加,其NSR催化活性呈上升趋势:当Au担载量不高于1.0%(质量分数,下同)时,分散度高,与载体Al₂O₃、Mn₂O₃之间存在强的相互作用力,导致在150℃条件下Au的氧化物难以被还原成活性组分Au⁰,所以没有活性;当Au担载量大于1.0%时,颗粒尺寸变大,与载体Al₂O₃、Mn₂O₃之间相互作用力变弱,使得Au的氧化物在150℃条件下较容易被还原成Au⁰,所以活性得到显著提升。当Au担载量为2.0%时,NO_x转化率和N₂选择性分别能够达到49.6%和71.9%。

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	董红文
	郭丽
	李新刚

关键词：金催化剂；三氧化二锰；低温； NO_x储存还原；稀燃技术；金属载体相互作用

Abstract：

A series of the Au/Al₂O₃/Mn₂O₃ catalysts with different Au loadings were prepared by the mechanical mixing method, and their catalytic activities on the NO_x storage-reduction (NSR) were studied. Results showed that the Au loading had the significant influence on the NSR activity. The catalyst showed very poor NSR activity when the Au loading was less than 1.0%. The reason might be that the low Au loading with a high gold dispersion would lead to a strong metal-support interaction over the Au/Al₂O₃/Mn₂O₃ catalyst. As a result, the gold oxides were difficultly reduced to Au⁰ at 150℃. Contrarily, the catalyst showed the much better NSR activity when the Au loading was above 1.0%. It is because the size of the Au particles increased with the increase of Au loading, which consequently induced the weaker metal-support interaction as compared with the low Au loading catalysts. Thus, the gold oxides could be readily reduced to Au⁰ at 150℃. Herein, the Au/Al₂O₃/Mn₂O₃ catalyst with the 2.0% Au loading presented the best NSR performance: the NO_x conversion and the N₂ selectivity could reach 49.6% and 71.9%, respectively.

Keywords： gold catalysts； Mn₂O₃； low temperature； NO_x storage and reduction； lean-burn technology； metal-support interaction

Received 2014-04-10;

Fund:

国家自然科学基金(U1232118),教育部新世纪优秀人才支持计划(NCET-10-0615)。

Corresponding Authors: 李新刚,E-mail:xingang_li@tju.edu.cn。 Email: xingang_li@tju.edu.cn

About author: 董红文(1987-),男,硕士,主要从事能源催化研究。

引用本文:

董红文, 郭丽, 李新刚.Au/Al₂O₃/Mn₂O₃催化剂的低温NO_x储存还原性能[J]. 化学工业与工程, 2016,33(3): 8-12,44

Dong Hongwen, Guo Li, Li Xingang.Performance of NO_x Storage and Reduction over Au/Al₂O₃/Mn₂O₃ Catalyst at Low Temperatures[J]. Chemcial Industry and Engineering, 2016,33(3): 8-12,44

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