Effects of supports on the iron based monolithic catalysts for NO reduction with propene

doi:10.16085/j.issn.1000-6613.2018-0150

Abstract

Abstract: Monolithic iron based catalysts supported on alumina, silica, and titania were prepared using the sol-gel and impregnation method, with which the selective catalytic reduction of NO with propene has been investigated. The catalysts were characterized by N₂-physisorption, XRD, SEM, H₂-TPR, Py-FTIR and in situ DRIFTS technologies. The supports had significant influence on the acid sites, redox properties, specific surface area, and surface morphology which resulted in the differences in the catalytic activity of NO reduction. The C₃H₆-SCR performance decreased with the used catalysts in the order as Fe/Al₂O₃/CM > Fe/SiO₂/CM > Fe/TiO₂/CM. Fe/Al₂O₃/CM showed the highest activity with a nitrogen oxide conversion of 100% in the presence of oxygen at 450℃, which is mainly attributed to its good redox properties and abundant Lewis acid sites. Based on the in situ DRIFT studies, the increase of Lewis acid sites enhanced the formation of NO₂/NO₃^- species, so as to promote the catalytic activity.

Key words: catalyst support, selective catalytic reduction(SCR), nitric oxide, propene, Lewis acid sites

摘要： 以Al₂O₃、SiO₂和TiO₂为载体，采用凝胶-溶胶法和浸渍法制备铁基堇青石整体式催化剂，并对其丙烯选择性催化还原NO性能进行了研究。通过N₂物理吸附/脱附、XRD、SEM、H₂-TPR、Py-FTIR和原位DRIFTS技术对催化剂进行了表征。不同载体对催化剂的表面酸性、氧化还原性能、比表面积和表面形貌有显著影响，从而导致丙烯还原NO的催化活性明显差异。C₃H₆-SCR的催化活性按Fe/Al₂O₃/CM > Fe/SiO₂/CM > Fe/TiO₂/CM依次降低。在450℃的有氧条件下，在Fe/Al₂O₃/CM上催化C₃H₆还原NO效率可达到100%，这主要是因为较好的氧化还原性能和丰富的Lewis酸性位。基于原位的DRIFTS研究表明，Lewis酸性位的增加有助于促进形成NO₂/NO₃^-物种，从而提高了催化性能。

关键词: 催化剂载体, 选择性催化还原, 一氧化氮(NO), 丙烯(C₃H₆), Lewis酸性位

CLC Number:

X511

ZHOU Hao, GE Mengyao, WU Shiguo, YE Bichao, SU Yaxin. Effects of supports on the iron based monolithic catalysts for NO reduction with propene[J]. Chemical Industry and Engineering Progress, 2018, 37(12): 4693-4700.

周皞, 葛梦瑶, 伍士国, 叶必朝, 苏亚欣. 载体对铁基整体式催化剂上丙烯催化还原NO的影响[J]. 化工进展, 2018, 37(12): 4693-4700.

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