State of iridium and its distribution in supported iridium catalysts

The presence of two oxidized forms of Ir, the ratio between which depends on its concentration, has been discovered in the surface layers of iridium catalysts obtained following the decomposition of adsorbed hexachloroiridic acid on Al/sub 2/O/sub 3/. The surface Ir/Al ratio is more than two times greater than the corresponding ratio calculated from the data from elemental analysis. The Cl/Al ratio is constant for all the sampling. The x-ray photoelectron spectra were recorded on a Varian IEE-15 spectrometer.