Changing active sites in Cu-CHA catalysts: deNOx selectivity as a function of the preparation method

被引:134
作者
Deka, Upakul [1 ,2 ]
Lezcano-Gonzalez, Ines [1 ,2 ]
Warrender, Stewart J. [3 ]
Picone, A. Lorena [3 ]
Wright, Paul A. [3 ]
Weckhuysen, Bert M. [1 ]
Beale, Andrew M. [1 ]
机构
[1] Univ Utrecht, Debye Inst Nanomat Sci, Inorgan Chem & Catalysis Grp, NL-3584 CA Utrecht, Netherlands
[2] Mat Innovat Inst M2i, NL-2628 CD Delft, Netherlands
[3] Univ St Andrews, EaStCHEM Sch Chem, St Andrews KY16 9ST, Fife, Scotland
关键词
NH3-SCR; Cu-SSZ-13; Cu-SAPO-34; CVD-IE; Active sites; COPPER-BASED CATALYSTS; NITRIC-OXIDE; RICH ATMOSPHERE; LOW-TEMPERATURE; N2O FORMATION; GASEOUS CUCL; ZEOLITE-Y; REDUCTION; NH3; NO;
D O I
10.1016/j.micromeso.2012.04.056
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
The selective catalytic reduction of NOx with ammonia (NH3-SCR) has been studied over Cu-CHA catalysts in which the loading of copper species was achieved using three different synthetic routes: two are based on post-synthetic treatment of the zeolite material (via aqueous or vapor phase) and a third involves the direct synthesis of a Cu-loaded SAPO-34. The catalysts were subsequently characterized by XRD, solid-state NMR, UV-vis and XAFS spectroscopies. Whilst the catalysts prepared via wet chemical routes show excellent deNO(x) activity and high selectivity to N-2, the one prepared via chemical vapor deposition gave the undesired product N2O in significant quantities. Isolated mononuclear Cu2+ ions in the vicinity of six-membered rings (6mrs, part of the d6r sub-units of CHA) were found to be active sites in both catalysts prepared via the wet chemical approaches. In contrast, XAFS data revealed that the catalyst prepared via chemical vapor deposition possesses Cu in two different environments: isolated Cu2+ cations and CuAlO2-type species. Catalytic experiments revealed a strong correlation between the number of isolated mononuclear Cu2+ in or near the plane of the 6m rings and N-2 production, whereas the presence of CuAlO2 species appears to promote the formation of undesired N2O. (C) 2012 Elsevier Inc. All rights reserved.
引用
收藏
页码:144 / 152
页数:9
相关论文
共 50 条
[1]   Selective catalytic reduction of nitric oxide with ammonia on copper(II) ion-exchanged offretite [J].
Arous, W ;
Tounsi, H ;
Djemel, S ;
Ghorbel, A ;
Delahay, G .
CATALYSIS COMMUNICATIONS, 2005, 6 (04) :281-285
[2]  
Arous W., 1883, SURF SCI, V2005, P158
[3]  
Binsted N., 1998, EXCURV CCLRC DARESBU
[4]   The State of the Art in Selective Catalytic Reduction of NOx by Ammonia Using Metal-Exchanged Zeolite Catalysts [J].
Brandenberger, Sandro ;
Kroecher, Oliver ;
Tissler, Arno ;
Althoff, Roderik .
CATALYSIS REVIEWS-SCIENCE AND ENGINEERING, 2008, 50 (04) :492-531
[5]  
Bull I., 2010, US Patent, Patent No. 0310440
[6]   Knowledge and know-how in emission control for mobile applications [J].
Burch, R .
CATALYSIS REVIEWS-SCIENCE AND ENGINEERING, 2004, 46 (3-4) :271-333
[7]   ROLE OF THE SUPPORT AND OF ADSORBED SPECIES ON THE BEHAVIOR OF CU-BASED CATALYSTS FOR NO CONVERSION [J].
CENTI, G ;
NIGRO, C ;
PERATHONER, S ;
STELLA, G .
CATALYSIS TODAY, 1993, 17 (1-2) :159-166
[8]   NATURE OF ACTIVE SPECIES IN COPPER-BASED CATALYSTS AND THEIR CHEMISTRY OF TRANSFORMATION OF NITROGEN-OXIDES [J].
CENTI, G ;
PERATHONER, S .
APPLIED CATALYSIS A-GENERAL, 1995, 132 (02) :179-259
[9]   Confirmation of Isolated Cu2+ Ions in SSZ-13 Zeolite as Active Sites in NH3-Selective Catalytic Reduction [J].
Deka, Upakul ;
Juhin, Amelie ;
Eilertsen, Einar A. ;
Emerich, Hermann ;
Green, Mark A. ;
Korhonen, Satu T. ;
Weckhuysen, Bert M. ;
Beale, Andrew M. .
JOURNAL OF PHYSICAL CHEMISTRY C, 2012, 116 (07) :4809-4818
[10]   The origin of N2O formation in the selective catalytic reduction of NOx by NH3 in O2 rich atmosphere on Cu-faujasite catalysts [J].
Delahay, G ;
Coq, B ;
Kieger, S ;
Neveu, B .
CATALYSIS TODAY, 1999, 54 (04) :431-438