以不同氧化物为载体,通过挤条成型法制备了Mo/ZSM-5催化剂,考察了其催化甲烷无氧芳构化反应性能.采用吸附吡啶红外光谱、氨程序升温脱附和氢程序升温还原等方法对催化剂进行了表征.结果表明,ZnO的添加使催化剂的强酸量减少,强B酸比例降低,Mo物种还原能力提高,因而催化剂表现出较高的甲烷芳构化活性和较低的积炭选择性.
The Mo/ZSM-5 catalysts extruded with various oxides as supports were prepared. Fourier transform infrared spectroscopy of pyridine adsorption, NH_3 temperature-programmed desorption, and H_2 temperature-programmed reduction were employed to characterize the catalysts. Methane dehydroaromatization in the absence of oxygen over the catalysts was investigated in a fixed-bed reactor. The results showed that the catalyst extruded with ZnO presented the highest activity among all the catalysts tested. Methane conversion and aromatics selectivity were 9.3% and 53.7%, respectively. The improved activity of the catalyst extruded with ZnO for methane dehydroaromatization was attributed to its appropriated Bronsted acidity. Moreover, addition of ZnO, an n-type semiconductor, benefited the reduction of Mo~(6+)species.
参考文献
| [1] | Wang L S;Tao L X;Xie M S;Xu G F Huang J S Xu Y D .[J].Catalysis Letters,1993,21:35. |
| [2] | Liu W;Xu Y D .[J].Journal of Catalysis,1999,185:386. |
| [3] | Szoke A;Solymosi F .[J].Applied Catalysis A:General,1996,142:361. |
| [4] | Weckhuysen BM.;Rosynek MP.;Lunsford JH.;Wang DJ. .Conversion of methane to benzene over transition metal ion ZSM-5 zeolites - I. Catalytic characterization[J].Journal of Catalysis,1998(2):338-346. |
| [5] | Wong S T;Xu Y D;Liu W;Wang L S Guo X X .[J].Applied Catalysis A:General,1996,136:7. |
| [6] | Xu Y D;Liu S T;Wang L S;Xie M S Guo X X .[J].Catalysis Letters,1995,30:135. |
| [7] | Sun C Y;Yao S D;Shen W J;Lin L W .[J].Catalysis Letters,2008,122:84. |
| [8] | 刘红梅,徐奕德.甲烷无氧芳构化反应催化剂Mo/HZSM-5的H2-TPR研究[J].催化学报,2006(04):319-323. |
| [9] | Honda K;Chen X;Zhang Z G .[J].Applied Catalysis A:General,2008,351:122. |
| [10] | 王建青,任冬梅,王祥生,李钢,刘海鸥.Mo/HZSM-5催化剂载体对甲烷无氧芳构化反应的影响[J].催化学报,2008(02):123-126. |
| [11] | 申文杰;徐奕德;包信和;李永刚,刘红梅 .[P].CN 03107379,2002. |
| [12] | Berndt H;Lietz G;Volter J .[J].Applied Catalysis A:General,1996,146:365. |
| [13] | Song Y;Sun C;Shen W;Lin L .Hydrothermal post-synthesis of HZSM-5 zeolite to enhance the coke-resistance of Mo/HZSM-5 catalyst for methane dehydroaromatization reaction: Reconstruction of pore structure and modification of acidity[J].Applied Catalysis, A. General: An International Journal Devoted to Catalytic Science and Its Applications,2007(1):266-274. |
| [14] | Wagner C .[J].Journal of Chemical Physics,1950,18:69. |
| [15] | Xu YD.;Bao XH.;Lin LW. .Direct conversion of methane under nonoxidative conditions[J].Journal of Catalysis,2003(1/2):386-395. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%