التفاصيل البيبلوغرافية
| العنوان: |
Study on doubly promoted W/MCM-22-based catalysts for dehydro-aromatization of CH4 in the absence of O-2 ; 甲烷无氧脱氢芳构化双促进W/MCM-22基催化剂研究 |
| المؤلفون: |
Huang,LQ, 黄利强, Zeng,JL, 曾金龙, Lin,GD, 林国栋, Yuan,YZ, 袁友珠, Zhang,HB, 张鸿斌 |
| سنة النشر: |
2004 |
| المجموعة: |
Xiamen University Institutional Repository |
| مصطلحات موضوعية: |
W/HZSM-5-BASED CATALYSTS, METHANE, DEHYDROGENATION, PERFORMANCE |
| الوصف: |
With incorporation of Ga3+/Zn2+ (or Co3+/2+/Mon+) into a W/MCM-22 host catalyst, highly active and heat-resistant doubly promoted W/MCM-22-based catalysts for dehydro-aromatization of methane ( abbreviated as DHAM) were prepared. Over an 8% W-0.1% Co-0.4% Mo/MCM-22 or 8% W-0.1% Ga-0.6% Zn/MCM-22 catalyst, 70% similar to 72% selectivity to benzene formation at similar to 15% conversion of CH4 could be achieved in the initial similar to 3 h of reaction under reaction condition of 0.1 MPa, 1073 K, GHSV = 1500 mL(STP) (.) h(-1) (.) (g-cat.)(-1). Addition of a proper amount of CO2 (less than or equal to 1.2%) or H-2 (similar to 7.0%) to the feed-gas was found to significantly enhance conversion of CH4 and selectivity to benzene, and to improve the performance of coke-resistance of the catalysts. By correlating the results of the NH3-TPD measurements and the catalyst tests, it was confirmed that intensity and concentration of the surface B-acid sites have pronounced effects on the performance of the catalyst for DHAM reaction. It was found experimentally that addition of a proper amount of Ga3+/Zn2+( or Co3+/2+/Mon+) into W/MCM-22 host catalyst resulted not only in eliminating parts of the strong surface B-acid sites but also in generating a kind of new medium-strung acid sites, mostly B-acid sites, simultaneously. The latter could serve as the catalytically active sites for DRAM reaction, and on such medium-strong surface B-acid sites, the formation of coke would be also alleviated to a greater extent. On the other hand, the doping of the Ga3+/Zn2+ (or Co3+/2+/Mon+)-components to tungsten oxide matrix would facilitate inhibiting aggregation of the W-containing active species and improving dispersion of the W-component at the surface of catalyst, thus leading to a pronounced decrease in the reduction-temperature for the hard-to-be-reduced W6+-species and an increase in quantity of the reducible W6+-species, as evidenced by the results of the H-2-TPR study. The above two roles that Ga3+/Zn2+ (or Co3+/2+/Mon+) as ... |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
English |
| تدمد: |
0567-7351 |
| Relation: |
Acta Chimica Sinica, 2004,62(18):1706-1712; WOS:000224063500007; http://dspace.xmu.edu.cn/handle/2288/62040 |
| الاتاحة: |
http://dspace.xmu.edu.cn/handle/2288/62040 |
| رقم الانضمام: |
edsbas.8D6D3D75 |
| قاعدة البيانات: |
BASE |