ISSN:
1572-879X
Keywords:
X-ray absorption of Ni-Cu
;
electronic structure of alloy catalysts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract X-ray absorption threshold resonances associated with LIII and LII absorption edges, which are attributed to excitation of electrons from 2p core levels to unoccupied d-states in the valence band, were investigated for a series of nickel-copper alloys of widely differing compositions. The catalysts were alloys in the form of metal powders with surface areas of the order of 1 m2/g. When the resonances for such samples are determined from measurements of the intensity of emission of electrons from the samples (i.e. by the so-called “electron yield” detection method), one can avoid experimental artifacts arising from the sample “thickness effect” encountered in X-ray transmission or fluorescence measurements. Edge resonances can then be determined reliably for metal powders. It was observed that copper had only a small attenuating effect on the resonances of nickel in the catalysts. The effect was smaller by an order of magnitude than that predicted by the rigid-band model of the electronic structure of nickel-copper alloys. The results provide strong support for earlier conclusions of others about the limitations of the rigid-band model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00765265
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