Open AccessEXAFS determination of the size of Co clusters on silica
Author(s) -
Arčon Iztok,
Tuel Alain,
Kodre Alojz,
Martin Guy,
Barbier Arnaud
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500019294
Subject(s) - extended x ray absorption fine structure , catalysis , metal , microporous material , coordination number , magic number (chemistry) , cluster (spacecraft) , scattering , analytical chemistry (journal) , materials science , chemistry , crystallography , absorption spectroscopy , computational chemistry , physics , electronic structure , organic chemistry , metallurgy , ion , computer science , optics , programming language , quantum mechanics
The metallic Co catalyst for the Fischer‐Tropsch reaction is prepared by reduction of Co salts impregnating microporous silica. The average size of the metallic Co clusters is determined from the average number of neighbours deduced from Co K‐edge EXAFS of catalyst samples. A model EXAFS signal constructed from the scattering paths of Co metal fcc lattice with lengths up to 5 Å is calibrated on a reference spectrum of Co metal foil. Catalyst spectra are interpreted with the same model expanded with variable neighbour fractions of the four nearest shells. Cluster size is obtained from comparison with the neighbour fractions of consecutive fcc magic‐number clusters.