TY - JOUR
T1 - Speciation of copper in ZSM-48 during NO reduction
AU - Huang, Y. J.
AU - Wang, H. Paul
AU - Lee, Jyh Fu
N1 - Funding Information:
The financial support of the National Science Council, Taiwan is gratefully acknowledged. We also thank Professor Y.W. Yang of the National Synchrotron Radiation Research Center and Professor C.-T. Yeh of the National Tsing Hua University for their EXAFS experimental assistance.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2003/1/28
Y1 - 2003/1/28
N2 - Speciation of copper in ZSM-48 and MCM-41 was studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies to reveal the abrupt changes in yields of N2O, NO2 and CO2 from the catalytic reduction of NO with CO at 673 K. Component fitted XANES spectra showed that oxygen was inserted into the metallic copper (Cu(0)) in ZSM-48 and MCM-41 during NO reduction. In the confined channels of ZSM-48, about 91% of total copper was Cu(I) that involved in the catalytic reduction of NO with CO at 673 K. By in situ EXAFS, we found that during the NO reduction process, the oxygen-inserted copper possessed Cu-O, Cu-Cu, and Cu-(O)-Cu bond distances of 1.88, 2.61 and 2.95 Å, respectively, suggesting the possible existence of a linear type cluster with an averaged structure of Cu2O in ZSM-48. Furthermore, in the channels of ZSM-48, due to the restricted diffusion, NO reduction as well as CO oxidation might primarily occur at the head or end of the clusters. Note that NO could penetrate into ZSM-48 containing the clusters. On the contrary, in the parallel experiment, mainly CuO was observed in the mesopores (∼32 Å) of MCM-41.
AB - Speciation of copper in ZSM-48 and MCM-41 was studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies to reveal the abrupt changes in yields of N2O, NO2 and CO2 from the catalytic reduction of NO with CO at 673 K. Component fitted XANES spectra showed that oxygen was inserted into the metallic copper (Cu(0)) in ZSM-48 and MCM-41 during NO reduction. In the confined channels of ZSM-48, about 91% of total copper was Cu(I) that involved in the catalytic reduction of NO with CO at 673 K. By in situ EXAFS, we found that during the NO reduction process, the oxygen-inserted copper possessed Cu-O, Cu-Cu, and Cu-(O)-Cu bond distances of 1.88, 2.61 and 2.95 Å, respectively, suggesting the possible existence of a linear type cluster with an averaged structure of Cu2O in ZSM-48. Furthermore, in the channels of ZSM-48, due to the restricted diffusion, NO reduction as well as CO oxidation might primarily occur at the head or end of the clusters. Note that NO could penetrate into ZSM-48 containing the clusters. On the contrary, in the parallel experiment, mainly CuO was observed in the mesopores (∼32 Å) of MCM-41.
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U2 - 10.1016/S0926-3373(02)00145-5
DO - 10.1016/S0926-3373(02)00145-5
M3 - Article
AN - SCOPUS:0037469281
SN - 0926-3373
VL - 40
SP - 111
EP - 118
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
IS - 2
ER -