以共沉淀法制备了LaFe_xMn_yAl_(12-x-y)O_(19)六铝酸盐催化剂,并用X射线衍射、扫描电镜、N_2吸附-脱附、紫外-可见漫反射光谱和穆斯馒尔谱对催化剂进行了表征,考察了催化剂上高浓度N_2O分解反应的性能.结果表明,在所考察的条件下,Mn比Fe更有利于促进六铝酸盐晶相的形成.LaFe_xAl_(12-x)O_(19)(x=0.5,1)中Fe以Fe~(3+)位于六铝酸盐尖晶石结构中的四面体位和镜面层结构中的三角双锥位,其中后者为N_2O分解的主要活性中心.LaMn_yAl_(12-y)O_(19)(y=0.5,1)中Mn优先以Mn~(2+)进入四面体位,然后以Mn~(3+)进入尖晶石结构中的八面体位,并成为N_2O分解的主要活性中心.
LaFe_xMn_yAl_(12-x-y)O_(19) hexaaluminate catalyst samples were prepared by a coprecipitation method and tested for N_2O decomposition with high concentration (30%, V/V). The catalyst samples were characterized by X-ray diffraction, scanning electron microscopy, N_2 adsorp-tion-desorption, ultraviolet-visible spectroscopy, and Mossbauer spectroscopy. The results showed that the partial substitution by Mn led to easier formation of phase-pure hexaaluminate compared with that by Fe under the investigated conditions. Fe~(3+) occupied both tetrahedral sites in spinel block and trigonal bipyramid sites in mirror plane for LaFe_xAl_ (12-x)O_(19)(x = 0.5,1) hexaaluminate. Mn~(2+) preferentially entered tetrahedral sites at low Mn content (y = 0.5) for LaMn_yAl_(12-y)O_(19) hexaaluminate, whereas Mn3+ entered octahedral sites in spinel block aty = 1. The activity tests for N_2O decomposition with high concentration demonstrated that Fe3～ in trigonal bipyramid sites of LaFe_xAl_(12-x)O_(19) and Mn~(3+) in octahedral sites of LaMn_yAl_(12-y)O_(19) were the main active centers.
参考文献
| [1] | Zakirov V;Lawrence T J;Sellers J J;Sweeting M N.[A].Brazil:Rio de Janeiro,2000 |
| [2] | Zakirov V;Goeman V;Lawrence T J;Sweeting M N.[A].Utah:Logan,2000 |
| [3] | Bellotto M.;Cristiani C.;Forzatti P.;Groppi G.;Artioli G. .On the crystal structure and cation valence of Mn in Mn-substituted Ba-beta-Al2O3[J].Journal of Catalysis,1998(2):597-605. |
| [4] | Groppi G;Cristiani C;Forzatti E .[J].Applied Catalysis B:Environmental,2001,35:137. |
| [5] | 徐金光,田志坚,王军威,徐云鹏,徐竹生,林励吾.超临界干燥方法对甲烷燃烧催化剂LaMnAl11O19结构及活性的影响[J].催化学报,2002(05):477-480. |
| [6] | Baylet A;Royer S;Marecot P;Tatibouet J M Duprez D .[J].Applied Catalysis B:Environmental,2008,81:88. |
| [7] | Svensson E E;Boutonnet M;Jaras S G .[J].Applied Catalysis B:Environmental,2008,84:241. |
| [8] | Zhu S M;Wang X D;Wang A Q;Cong Y,Zhang T.[J].Chemical Communications,2007:1695. |
| [9] | Zhu S M;Wang X D;Wang A Q;Zhang T .[J].Catalysis Today,2008,131:339. |
| [10] | Perez-Ramirez J;Santiago M .Metal-substituted hexaaluminates for high-temperature N2O abatement[J].Chemical communications,2007(6):619-621. |
| [11] | Santiago M;Perez-Ramirez J .Decomposition of N2O over hexaaluminate catalysts[J].Environmental Science & Technology: ES&T,2007(5):1704-1709. |
| [12] | Machida M;Eguchi K;Arai H .[J].Journal of Catalysis,1990,123:477. |
| [13] | 李彤,张科,刘说,豆立新,李永丹.CaxLa1-xMnAl11O19 六铝酸盐催化剂上甲烷的催化燃烧[J].催化学报,2007(09):783-788. |
| [14] | Zhang Q H;Wang Y;ltsuki S;Shishido T Takehira K .[J].Journal of Molecular Catalysis A:Chemical,2002,188:189. |
| [15] | Mileila F;Gallardo-Amores J M;Baldi M;Busca G .[J].Journal of Materials Chemistry,1998,8:2525. |
| [16] | Laville F;Gourier D;Lejus A M;Vivien D .[J].Journal of Solid State Chemistry,1983,49:180. |
| [17] | Artizzu-Duart P;Brulle Y;Gaillard F;Guilhanme N Primet M .[J].Catalysis Today,1999,54:181. |
| [18] | Li S Q;Wang X L .[J].Journal of Alloys and Compounds,2007,432:333. |
| [19] | Artizzu-Duart P;Millet J M;Guilhaume N;Garbowski E Primet M .[J].Catalysis Today,2000,59:163. |
| [20] | Groppi G.;Forzatti P.;Cristiani C. .BAFEXAL(12-X)O-19 SYSTEM FOR HIGH-TEMPERATURE CATALYTIC COMBUSTION - PHYSICO-CHEMICAL CHARACTERIZATION AND CATALYTIC ACTIVITY[J].Journal of Catalysis,1997(1):95-103. |
| [21] | 蒋政,李进军,郝郑平,侯红霞,许秀艳,胡春.铁取代六铝酸盐的制备及其对甲烷燃烧的催化性能[J].催化学报,2004(06):485-489. |
| [22] | Wang X D;Zhao X Q;Shen J Y;Sun X Y Zhan8 T Lin L W .[J].Physical Chemistry Chemical Physics,2002,4:2846. |
| [23] | Petrovic S;Terlecki-Baricevic A;Karanovic L;KirilovStefanov P Zdujic M Dondur V Paneva D Mitov I Rakic V .[J].Applied Catalysis B:Environmental,2008,79:186. |
| [24] | Kuhn J N;Matter P H;Millet J M M;Watson R B Ozkan U S .[J].Journal of Physical Chemistry C,2008,112:12468. |
| [25] | Glasser F P;Woodhams F W;Meads R E .[J].Journal of Solid State Chemistry,1972,5:255. |
| [26] | Tronc E;Laville F;Gasperin M;Lejus A M Vivien D .[J].Journal of Solid State Chemistry,1989,81:192. |
| [27] | Machida M;Sato A;Kijima T;Inoue H Eguchi K .[J].Catalysis Today,1995,26:239. |
| [28] | Gardner T H;Shekhawat D;Berry D A;Smith M W Salazar M Kugler E L .[J].Applied Catalysis A:General,2007,323:1. |
| [29] | Kikuchi R;Iwasa Y;Takeguchi T;Eguchi K .[J].Applied Catalysis A:General,2005,281:61. |
| [30] | Machida M;Shiomitsu T;Eguchi K;Arai H Shimizu Y .[J].Journal of Solid State Chemistry,1991,95:220. |
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