TY - JOUR
T1 - Speciation and distribution of copper and zinc in MCM-41
AU - Huang, Hsin Liang
AU - Wang, H. Paul
AU - Chang, Juu En
AU - Wei, Yu Ling
N1 - Funding Information:
The financial supports of the Taiwan National Science Council and National Synchrotron Radiation Research Center (NSRRC) are gratefully acknowledged. We also thank Prof. Y.W. Yang and Dr. J.-F. Lee of the NSRRC for their helps in the EXAFS experiments.
PY - 2007/5
Y1 - 2007/5
N2 - 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 Å with the coordination number (CN) of 3.3. A decrease of the Zn-O bond distance (1.94 Å) at 1173 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.
AB - 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 Å with the coordination number (CN) of 3.3. A decrease of the Zn-O bond distance (1.94 Å) at 1173 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.
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U2 - 10.1016/j.elspec.2006.12.006
DO - 10.1016/j.elspec.2006.12.006
M3 - Article
AN - SCOPUS:34247164569
SN - 0368-2048
VL - 156-158
SP - 357
EP - 360
JO - Journal of Electron Spectroscopy and Related Phenomena
JF - Journal of Electron Spectroscopy and Related Phenomena
ER -