Ni-Mn bi-metal oxide catalysts for the low temperature SCR removal of NO with NH3

• Published in: Applied catalysis. B, Environmental Vol. 148-149; pp. 114 - 122
• Main Authors: Wan, Yaping, Zhao, Wenru, Tang, Yu, Li, Liang, Wang, Huijun, Cui, Yunlong, Gu, Jinlou, Li, Yongsheng, Shi, Jianlin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 27.04.2014; Elsevier
• Subjects: Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Lewis acid sites; Low temperature NO-SCR; Nickel and manganese mixed oxides; Surface Mn4+ active species; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Nickel and manganese mixed oxides; Surface Mn4+ active species; Lewis acid sites; Low temperature NO-SCR; Lewis acid; Lewis site; Acidic site; Transition metal; Surface Mn; active species; Chemical reduction; Ammonia; Heterogeneous catalysis; Manganese oxides; Nickel; Catalyst; Low temperature; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.10.049

•The catalysts were prepared by co-precipitation with various molar ratios of Ni/Mn.•The Ni(0.4)-MnOx catalyst obtained 85% of NO conversion at 95°C.•The addition of nickel enhanced the concentration and acidity of Lewis acid sites.•A synergetic effect through electron transfer between Mn and Ni was proposed. A series of nickel–manganese bi-metal oxide catalysts of different Ni/Mn ratios were prepared by a co-precipitation method for the low temperature selective catalytic reduction (SCR) of NO with NH3 in the presence of excess O2. The NO conversion over different catalysts decreased in the following sequence of Ni(0.4)-MnOx>MnOx>> Ni(1)-MnOx>Ni(2.5)-MnOx>NiOx. The Ni(0.4)-MnOx catalyst showed the highest catalytic activity, 85% of NO conversion at 95°C and 100% from 120 to 240°C, among the catalysts investigated. The TPR, XPS, NH3-TPD and in situ FTIR results revealed that Mn4+ was the main active species for SCR reaction and the addition of nickel species enhanced the surface concentration and acidity of Lewis acid sites. A possible synergetic catalytic effect was proposed for the low temperature SCR reaction through the electron transfer between Mn and Ni ions.