کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5397106 | 1505775 | 2007 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Speciation and distribution of copper and zinc in MCM-41
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Speciation and distribution of copper and zinc in the channels of the surface modified MCM-41 (MCM-41-SH) (pore opening = 2.6 nm) has been studied by X-ray absorption near edge structural (XANES) and X-ray absorption fine structural (EXAFS) spectroscopies in the present work. By least-square fitted XANES spectroscopy, mainly CuO and ZnO are observed in the channels of MCM-41-SH after calcination at 298-1173 K. Interestingly, a small amount of Cu-Zn alloys is also found in the MCM-41-SH at the calcination temperature of 573 K. At T > 573 K, nanosize CuO and Zn2SiO4 are the copper and zinc compounds in the MCM-41-SH. Due to aggregation of nanosize CuO at 1173 K, the bond distance of Cu-O is increased to 1.97 Ã
with the coordination number (CN) of 3.3. A decrease of the Zn-O bond distance (1.94Â Ã
) at 1173Â K is also observed. This work is also an example of the usefulness of the XANES and EXAFS spectroscopies for revealing the chemical structure of copper and zinc and possible reaction paths in the channels of MCM-41-SH during calcination at elevated temperatures.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electron Spectroscopy and Related Phenomena - Volumes 156â158, May 2007, Pages 357-360
Journal: Journal of Electron Spectroscopy and Related Phenomena - Volumes 156â158, May 2007, Pages 357-360
نویسندگان
Hsin-Liang Huang, H. Paul Wang, Juu-En Chang, Yu-Ling Wei,