采用共沉淀法制备了新型CeO2-WO3复合氧化物催化剂,并用于氨选择性催化还原(NH3-SCR)NOx反应中.活性测试表明,在200～450℃ NOx转化率接近100%.采用程序升温脱附和原位漫反射红外光谱研究了该催化剂上的NH3-SCR反应机理.结果表明,该催化剂的主要活性位是CeO2,而WO3的加入大大提高了其表面Br(o)nsted酸位的数量与强度及其氧化NO的能力.另外还发现,除了催化剂表面Lewis酸与Br(o)nsted酸参与反应外,表面的桥式与单齿硝酸盐也是活性很高的物种.整个SCR反应可通过以上两种途径进行.
The mechanism of NH3-selective catalytic reduction (SCR) over a CeO2-WO3 catalyst was investigated by temperature-programmed desorption (TPD) analysis and in situ diffuse reflectance infrared Fourier transform spectroscopy. The active sites were on CeO2, while WO3 greatly enhanced the amount and strength of the surface Brdnsted acid sites and the NO oxidation ability. Both NR4+ and coordinated NH3 contributed to the SCR reaction. Bridging nitrate and monodentate nitrate were confirmed as the reactive nitrate species. Under SCR reaction conditions, surface NH4NO3 was formed, which played the role of an important intermediate species. Two different pathways for the SCR reaction were suggested for the CeO2-WO3 catalyst.
参考文献
| [1] | Bosch H;Janssen F J .[J].Catalysis Today,1988,2:369. |
| [2] | Dunn J P;Koppula P R;Stenger H G;Wachs I E .[J].Applied Catalysis B:Environmental,1998,19:103. |
| [3] | Liu F D;He H;Zhang C B.[J].Chemical Communications,2008:2043. |
| [4] | Xu W Q;Yu Y B;Zhang C B;He H .[J].Catalyst Communication,2008,9:1453. |
| [5] | Gao X;Jiang Y;Zhong Y;Luo Z Y Cen K F .[J].Journal of Hazardous Materials B:Environmental Technologies,2010,174:734. |
| [6] | Shen Y S;Zhu S M;Qiu T;Shen S B .[J].Catalyst Communication,2009,11:20. |
| [7] | Si Z C;Weng D;Wu X D;Li J,LiG .[J].Journal of Catalysis,2010,271:43. |
| [8] | Gu T T;Liu Y;Weng X L;Wang H Q Wu Z B .[J].Catalyst Communication,2010,12:310. |
| [9] | Chen L;Li J H;Ge M F;Zhu R H .[J].Catalysis Today,2010,153:77. |
| [10] | Chen L;Li J H;Ge M F .[J].Journal of Physical Chemistry C,2009,113:21177. |
| [11] | Chen L;Li J H;Ge M F .[J].Environmental Science and Technology,2010,44:9590. |
| [12] | Chen L;Li J H;Ge M F.[J].ACS Catal |
| [13] | Tronconi E.;Forzatti P.;Malloggi S.;Lietti L. .EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE DYNAMICS OF THE SCR - DENOX REACTION[J].Chemical Engineering Science,1996(11):2965-2970. |
| [14] | Eigenmann F;Maciejewski M;Baiker A .[J].Applied Catalysis B:Environmental,2006,62:311. |
| [15] | Shimizu K;Satsuma A;Hattori T .[J].Applied Catalysis B:Environmental,1998,16:319. |
| [16] | Rarais G;Busca G;Bregani F;Forzatti P .[J].Applied Catalysis A:General,1990,64:259. |
| [17] | Ramis G;Yi L;Busca G .[J].Catalysis Today,1996,28:373. |
| [18] | Matralis H K;Ciardelli M;Ruwet M;Grange P .[J].Journal of Catalysis,1995,157:368. |
| [19] | Kijlstra WS.;Smit HI.;Poels EK.;Bliek A.;Brands DS. .MECHANISM OF THE SELECTIVE CATALYTIC REDUCTION OF NO BY NH3 OVER MNOX/AL2O3 .2. REACTIVITY OF ADSORBED NH3 AND NO COMPLEXES[J].Journal of Catalysis,1997(1):219-230. |
| [20] | Ramis G;Larrubia M A .[J].Journal of Molecular Catalysis A:Chemical,2004,215:161. |
| [21] | Larrubia M A;Ramis G;Busca G .[J].Applied Catalysis B:Environmental,2001,30:101. |
| [22] | Lamibia M A;Ramis G;Busca G .[J].Applied Catalysis B:Environmental,2000,27:L145. |
| [23] | Lin S D;Gluhoi A C;Nieuwenhuys B E .[J].Catalysis Today,2004,90:3. |
| [24] | Chen J P;Yang R T .[J].Applied Catalysis A:General,1992,80:135. |
| [25] | Choi EY.;Kim YG.;Nam IS. .TPD STUDY OF MORDENITE-TYPE ZEOLITES FOR SELECTIVE CATALYTIC REDUCTION OF NO BY NH3[J].Journal of Catalysis,1996(2):597-604. |
| [26] | Qi G S;Yang R T;Chang R .[J].Applied Catalysis B:Environmental,2004,51:93. |
| [27] | Mart'inez-Arias A;Soria J;Conesa J C;Seoane X L,Arcoya A,Catalu(n)a R .[J].Journal of the Chemical Society,Faraday Transactions,1995,91:1679. |
| [28] | Hadjiivanov KI. .Identification of neutral and charged NxOy surface species by IR spectroscopy [Review][J].Catalysis Reviews. Science and Engineering,2000(1/2):71-144. |
| [29] | Underwood G M;Miller T M;Grassian V H .[J].Journal of Physical Chemistry A,1999,103:6184. |
| [30] | Liu F D;He H .[J].Catalysis Today,2010,153:70. |
| [31] | Komatsu T;Ogawa T;Yashima T .[J].Journal of Physical Chemistry,1995,99:13053. |
| [32] | Salker A V;Weiweiler W .[J].Applied Catalysis A:General,2000,203:221. |
| [33] | Centi G.;Perathoner S. .ADSORPTION AND REACTIVITY OF NO ON COPPER-ON-ALUMINA CATALYSTS .2. ADSORBED SPECIES AND COMPETITIVE PATHWAYS IN THE REACTION OF NO WITH NH3 AND O-2[J].Journal of Catalysis,1995(1):93-102. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%