Site-selective XAFS Spectroscopy Tuned to Surface Active Sites of Cu/ZnO and Cr/SiO2 Catalysts
Y. Izumi, H. Nagamori, F. Kiyotaki, and T. Minato
J. Synchrotron Rad., 605 - 607, 8 (2001).
XAFS (X-ray absorption fine structure) spectra were measured by using the fluorescence spectrometer for the emitted X-ray from sample. The chemical shifts between Cu(0) and Cu(I) and between Cr(III) and Cr(VI) were evaluated. Tuning the fluorescence spectrometer to each energy, the Cu(0) and Cu(I) site-selective XANES for Cu/ZnO catalyst were measured. The first one was similar to the XANES of Cu metal and the second one was the 5 : 5 average of XANES for Cu(I) sites + Cu metal. The population ratio of copper site of the Cu/ZnO catalyst was found to be Cu metal : Cu2O : Cu(I) atomically dispersed on surface = 70(+-23) : 22(+-14) : 8(+-5). Site-selective XANES for Cr(III) site of Cr/SiO2 catalyst was also studied.
Chiba University > Graduate School of Science > Department of Chemistry > Dr. Yasuo Izumi Group