Iridium catalysts lines

Lj absorption edges for iridium catalysts under various conditions (heavier lines) aligned with the same edge in the bulk metal. The difference spectrum shown below each pair of edge spectra was obtained by subtracting the bulk metal edge from the Catalyst edge. 

In studies of the platinum-iridium system in the bulk, Raub and Platte (47) have reported a miscibility gap at temperatures lower than about 975°C. At 500°C the gap extends over the composition range from 7 to 99% iridium. Nevertheless, the results presented in Figure 4.23 indicate that it is possible to prepare platinum-iridium catalysts for which X-ray diffraction patterns do not reveal separate lines for platinum-rich and iridium-rich phases, despite the fact that the catalysts have been heated to only 500°C in their preparation. Instead, single diffraction lines are observed. 

Figure 4.31 Contributions of the platinum L, EXAFS, represented by the dotted lines in the fields labeled b, and the function I,IK), represented by the dotted lines in the fields labeled c, to the extended fine structure (solid lines) associated with the platinum fin edges of platinum-iridium catalysts (48). [In each field labeled a the dotted line was determined by fitting the expression for the sum of the platinum EXAFS and the function /,(X) to the solid line, which was obtained from Figure 4.26.] (Reprinted with permission from the American Institute of Physics.)...

Figure 15.7 Experimental points ( ) and calculated curves (line) using the autocatalytic mechanism (rate constants k, and (C2) for the formation of iridium nanoclusters during 1-decene hydrogenation by the catalyst precursor [lr(COD)Cl]2 under 4atm of molecular hydrogen in (a) BMI PFs ...

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