TY - JOUR
T1 - A Development of EXAFS and XANES Measurements in the Laboratory— An Application to Silica-Supported Cu-Rh Bimetallic Catalyst—
AU - Tohji, Kazuyuki
AU - Udagawa, Yasuo
AU - Harada, Mutsumi
AU - Ueno, Akifumi
PY - 1986
Y1 - 1986
N2 - An attempt was made to improve an extended X-ray absorption fine structure (EXAFS) facility by the use of higher-order reflections from dispersing crystals. A resolution good enough to observe X-ray absorption near edge structure (XANES) has been obtained in the lower energy region (5~10 keV), and EXAFS measurements have been extended to cover up to about 26 keV, including K absorption edges of Ru, Rh, Pd, and Ag, which are important in catalysis. Some examples of the performances of this spectrometer are presented. By making use of the spectrometer, local structures around Cu and Rh atoms in Cu-Rh/SiO2 catalysts have been studied by the EXAFS of Cu and Rh and also by the XANES of Cu. The catalysts prepared by two kinds of preparation procedures, the impregnation method and the alkoxide method, have been examined. In the catalysts prepared by both methods, Rh atoms are in the metallic environment and surrounded by other Rh atoms, but Cu atoms are not. It is concluded that Cu atoms have both Cu and Rh neighbors and are concentrated on the surface. The tendency is more pronounced in the catalyst prepared by the alkoxide method, indicating a difference in the metal particle size of the two catalysts prepared by the different methods.
AB - An attempt was made to improve an extended X-ray absorption fine structure (EXAFS) facility by the use of higher-order reflections from dispersing crystals. A resolution good enough to observe X-ray absorption near edge structure (XANES) has been obtained in the lower energy region (5~10 keV), and EXAFS measurements have been extended to cover up to about 26 keV, including K absorption edges of Ru, Rh, Pd, and Ag, which are important in catalysis. Some examples of the performances of this spectrometer are presented. By making use of the spectrometer, local structures around Cu and Rh atoms in Cu-Rh/SiO2 catalysts have been studied by the EXAFS of Cu and Rh and also by the XANES of Cu. The catalysts prepared by two kinds of preparation procedures, the impregnation method and the alkoxide method, have been examined. In the catalysts prepared by both methods, Rh atoms are in the metallic environment and surrounded by other Rh atoms, but Cu atoms are not. It is concluded that Cu atoms have both Cu and Rh neighbors and are concentrated on the surface. The tendency is more pronounced in the catalyst prepared by the alkoxide method, indicating a difference in the metal particle size of the two catalysts prepared by the different methods.
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U2 - 10.1246/nikkashi.1986.1553
DO - 10.1246/nikkashi.1986.1553
M3 - Article
AN - SCOPUS:85016525386
VL - 1986
SP - 1553
EP - 1559
JO - Nippon Kagaku Kaishi / Chemical Society of Japan - Chemistry and Industrial Chemistry Journal
JF - Nippon Kagaku Kaishi / Chemical Society of Japan - Chemistry and Industrial Chemistry Journal
SN - 0369-4577
IS - 11
ER -