以La2O3,Mn(NO3)2和Al(NO3)3·9H2O为主要原料,用"溶胶-凝胶"法结合"超临界干燥技术"分别制备260 ℃超细镧锰和镧锰铝气凝胶; 煅烧制备850 ℃超细镧锰和镧锰铝气凝胶.用XRD,TEM等手段对样品进行表征,重点考察pH值、 温度等因素对制备的影响,并用CO与NO的反应来比对镧锰气凝胶和镧锰铝气凝胶的催化活性.结果表明: (1) 制得镧锰气凝胶为疏松、 具有较好分散性的棕黑色粉末; 260 ℃时,镧锰气凝胶由絮状物包裹着若干球形大颗粒组成,球形颗粒直径小于80 nm; 而絮状物尺寸范围跨度较大,大的约为500 nm×150 nm,小的直径约为几个纳米; 850 ℃时,镧锰气凝胶结晶度提高,颗粒感增强,并且颗粒间发生一定程度的烧结,煅烧产物为LaMnO3+λ和Mn3O4,球形颗粒粒径小于20 nm; (2)镧锰铝气凝胶外观疏松、分散性好、 呈棕色; 260 ℃时,镧锰铝气凝胶结晶度较低; 850 ℃时,镧锰铝气凝胶结晶度提高,主要晶相物质包括: LaMnO3+λ,La2O3、 不同价态氧化锰和γ-Al2O3; (3)铝的引入,改变了气凝胶微结构单元,降低了起燃温度,但同时也降低了NO的最终转化率; (4) 超细镧锰气凝胶对CO与NO反应有较好的催化活性.
参考文献
| [1] | Guido Saracco;Giovanni Scibilia;Antonio Iannibello;Giancarlo Baldi .Methane combustion on Mg-doped LaCrO_3 perovskite catalysts[J].Applied Catalysis, B. Environmental: An International Journal Devoted to Catalytic Science and Its Applications,1996(2):229-244. |
| [2] | Davide F;Lucio F.Methane combustion on some perovskite-like mixed oxides[J].Applied Catalysis B:Environmental,1998:119. |
| [3] | Seiyama T .Toal oxidation of hydrocarbons on perovskite oxides[J].Catalysis Review-Science and Engineering,1992,34:281. |
| [4] | 陈爱平;马建新;方明 等.钙钛矿结构在CO还原SO2催化脱硫中的作用[J].催化学报,1998,19(04):320. |
| [5] | Yong Fang;Yu Yao .The oxidation of hydrocarbons and CO over metal oxides Ⅳ perovskites-type oxides[J].Journal of Catalysis,1975,36:266. |
| [6] | Gysling H J;Monnier J R;Apai G .Synthesis charaterization and catalytic activity of LaRhO3[J].Journal of Catalysis,1987,103(02):407. |
| [7] | Klimisch R H;Larson J G.The Catalytic Chemistry of Nitrogen Oxides[M].New York: Plenum Press,1975:215. |
| [8] | Rojas M L;Fierro J L G;Tejuca L G et al.Preparation and chracterization of LaMn1-xCuxO3+λ perovskite oxides[J].Journal of Catalysis,1990,124:41. |
| [9] | Arai H;Hamada J;Eguchi K et al.Catalytic combustion of methane over various perovskite-type oxides[J].Applied Catalysis,1986,26:265. |
| [10] | Yoldas B E .Aluminum sol preparation from alkoxides[J].American Ceramic Society Bulletin,1975,54:289. |
| [11] | Wu S J;de Jonghe L C .Sintering of γ-Al2O3[J].Journal of the American Ceramic Society,1996,79(08):2207. |
| [12] | Gallas M R;Hochey B;Pechenik A et al.Fabrication of transparent γ-Al2O3 from nanosize particles[J].Journal of the American Ceramic Society,1991,77(08):2107. |
| [13] | 淳远;朱建华;须沁华 等.醇盐水解法制备Al2O3-Nay新型复合多孔催化材料[J].催化学报,1997,18(04):368. |
| [14] | 魏迎旭,许磊,齐越,王公慰.微波条件下结晶γ-Al2O3的制备与表征[J].催化学报,1999(03):243-246. |
| [15] | 张敬畅,曹维良,于定新,石锦华,窦正仓.超临界流体干燥法制备纳米级TiO2的研究[J].无机材料学报,1999(01):29-35. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%