کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10244568 | 47694 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Possible reasons for the superior performance of zeolite-based catalysts in the reduction of nitrogen oxides
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Possible reasons for the superior performance of zeolite-based catalysts in the reduction of nitrogen oxides Possible reasons for the superior performance of zeolite-based catalysts in the reduction of nitrogen oxides](/preview/png/10244568.png)
چکیده انگلیسی
Literature data and results obtained in this laboratory are used to compare catalysts supported on either zeolites or amorphous oxides and used in NOx reduction to N2. The data show that the catalytic activity of the zeolite-based materials is higher if alkanes, alkenes, or organic oxygenates are used as reductants, but with ammonia the performance of both groups of catalysts is comparable. These findings are rationalized in the context of the present knowledge of the mechanism of NOx reduction. Transition metals form oxo-ions on zeolites, but solid solutions on alumina. On zeolites, optimal Coulomb stabilization can be achieved if heterolytic dissociation of molecules transforms multipositive cations to monopositive cations. N2O4 dissociates to form NO++NO3â on BaNa/Y. In contrast, no NO+ ions are detected on BaO/γ-Al2O3. Another important parameter is the high heat of adsorption of small molecules in the narrow zeolite pores. Because oxygenates are superior to alkanes in competing against water for active sites, NOx reduction with alkanes is favored by zeolites with low Al/Si ratios, but NOx reduction with acetaldehyde is more efficient on a faujasite with a high Al/Si ratio. Over these catalysts, water vapor actually enhances NOx reduction by preventing formation of crotonaldehyde, which would poison catalyst sites.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 235, Issue 1, 1 October 2005, Pages 201-208
Journal: Journal of Catalysis - Volume 235, Issue 1, 1 October 2005, Pages 201-208
نویسندگان
Meijun Li, Younghoon Yeom, Eric Weitz, Wolfgang M.H. Sachtler,