Selective catalytic reduction of NO to N2 with copper and cobalt exchanged ZSM-5 zeolites: the effect of calcium addition

Journal of the Brazilian Chemical Society

Universidade Federal de São Carlos, São Carlos, Brazil¹  Martins, Leandro¹  Wallau, Martin¹  Peguin, Robson Pablo S.¹  Urquieta-González, Ernesto Antonio¹ 

关键词: NO reduction;    exchanged ZSM-5 zeolites;    copper;    cobalt;    calcium;   

DOI  :  10.1590/S0103-50532005000400016

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

ZSM-5 catalysts containing either Cu or Co cations individually or Cu/Ca or Co/Ca cation combinations were prepared by ion exchange. These materials were tested as catalysts for the reduction of NO to N2 in the presence of propane or methane. Cu2+ and [Cu-O-Cu]2+ species were identified in ion exchangeable sites in the copper-containing catalysts. The amount of the latter cation increased with increasing copper content and in the presence of Ca2+ and was the most active in the reduction of NO. However, at temperatures higher than 400 ºC its activity decreased markedly. For cobalt-exchanged zeolites, Co2+ in charge-compensation sites or Co3+ in extra-framework precipitates were present in the catalysts. It was verified that the amount of Co3+ diminished with the presence of Ca2+. For the catalysts prepared in this study no significant differences in specific activity for the reduction of NO or for methane oxidation were observed in the presence of calcium.

【 授权许可】

Unknown