CATALYST STRUCTURE STUDIED BY A LABORATORY EXAFS FACILITY : Ru/Al2O3

A laboratory EXAFS spectrometer is described which features the utilization of higher order reflections from curved dispersing crystal. With this spectrometer a sufficient performance for structural analyses are obtained in the high energy region up to about 25 keV. It was applied to structurally characterize two kinds of Ru/Al2O3 catalysts, prepared from RuCl3 and Ru3(CO)12, by the Ru K EXAFS, combined with H2 adsorption and EM observations. It was found that Ru metal particles of different sizes were formed depending on the starting material and the procedure. In the catalyst prepared from Ru3(CO)12, small metal particles, possibly consist of about 20 atoms, are formed. They are small enough to show a contraction of the nearest neighbor distance by 0.06 A