Reactivity of V2O5-WO3/TiO2 de-NOx catalysts by transient methods

被引:54
作者
Lietti, L
机构
[1] Dipto. di Chim. Industriale ed I., Politecnico di Milano, 20133 Milano
关键词
vanadium; titanium; SCR reaction; TPSR; TPR;
D O I
10.1016/S0926-3373(97)80001-X
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The reactivity of ternary V2O5-WO3/TiO2 de-NO(x)ing catalysts with compositions similar to those of commercial catalysts (WO3 ca. 9% w/w, V2O5 < 2% w/w) is investigated by transient techniques (temperature programmed desorption, TPD; temperature programmed surface reaction, TPSR; and temperature programmed reaction, TPR). The results indicate that the reactivity of the ternary catalysts in the SCR reaction increases on increasing the vanadia loading, and that the ternary catalysts are more active than the corresponding binary vanadia-titania samples with the same V2O5 loading. Indeed the SCR reaction is monitored at lower temperatures and high NO conversions are also preserved at high temperatures. TPSR and TPR data show that at low temperatures the SCR reaction occurs via a redox mechanism that involves at first the participation of the catalyst lattice oxygen and then the reoxidation of the reduced sites by gas-phase oxygen. Based on TPSR and TPR data, the higher reactivity of the ternary catalysts has been related to their superior redox properties, in line with previous chemico-physical characterisation studies. The catalyst redox properties thus appear as a key-factor in controlling the reactivity of V2O5-WO3/TiO2 de-NO(x)ing catalysts at low temperatures. The results also show that at high temperatures the surface acidity plays an important role in the adsorption and activation of ammonia.
引用
收藏
页码:281 / 297
页数:17
相关论文
共 33 条
[1]   REACTIVITY AND PHYSICOCHEMICAL CHARACTERIZATION OF V2O5-WO3/TIO2 DE-NOX CATALYSTS [J].
ALEMANY, LJ ;
LIETTI, L ;
FERLAZZO, N ;
FORZATTI, P ;
BUSCA, G ;
GIAMELLO, E ;
BREGANI, F .
JOURNAL OF CATALYSIS, 1995, 155 (01) :117-130
[2]  
BELL AT, 1985, CATAL REV SCI ENG, V27, P1
[3]  
Bond G. C., 1987, CATAL TODAY, V1, P229
[4]  
Bosch H., 1986, CATAL TODAY, V2, P369, DOI DOI 10.1016/0920-5861(88)80002-6
[5]   ROLE OF WO3 IN MIXED V2O5-WO3/TIO2 CATALYSTS FOR SELECTIVE CATALYTIC REDUCTION OF NITRIC-OXIDE WITH AMMONIA [J].
CHEN, JP ;
YANG, RT .
APPLIED CATALYSIS A-GENERAL, 1992, 80 (01) :135-148
[6]   ON THE MORPHOLOGICAL PROPERTIES OF TUNGSTA-TITANIA DE-NOXING CATALYSTS [J].
CRISTIANI, C ;
BELLOTTO, M ;
FORZATTI, P ;
BREGANI, F .
JOURNAL OF MATERIALS RESEARCH, 1993, 8 (08) :2019-2025
[7]   EFFECT OF ADDITIVES ON THE STRUCTURE AND REACTIVITY OF THE SURFACE VANADIUM-OXIDE PHASE IN V2O5 TIO2 CATALYSTS [J].
DEO, G ;
WACHS, IE .
JOURNAL OF CATALYSIS, 1994, 146 (02) :335-345
[8]   REACTIVITY OF SUPPORTED VANADIUM-OXIDE CATALYSTS - THE PARTIAL OXIDATION OF METHANOL [J].
DEO, G ;
WACHS, IE .
JOURNAL OF CATALYSIS, 1994, 146 (02) :323-334
[9]  
Forzatti P, 1996, HETEROGEN CHEM REV, V3, P33, DOI 10.1002/(SICI)1234-985X(199603)3:1<33::AID-HCR54>3.0.CO
[10]  
2-R