Nature of the metal-support interface in supported metal catalysts: results from x-ray absorption spectroscopy

X-ray absorption spectra characterizing the metal-support interface in supported metal complexes and supported metal catalysts are summarized and evaluated with 29 refs. Mononuclear transition metal complexes on non-reducible metal oxide supports are bonded with metal-oxygen bonds of .apprx.2.15 .ANG.; the bonding distance is only weakly sensitive to the oxidn. state of the metal. Nearly this same metal-oxygen distance is characteristic of the metal-support interface in oxide-supported metal clusters following high temp. redn. in H2. When the supported metals are treated in H2 at low temps.