ADSORPTION OF N2, O2, N2O AND NO ON IR(111) BY EELS AND TPD

Adsorption of N2, O2, N2O and NO on a clean Ir(111) surface at 84 K has been studied by high resolution EELS and TPD. N2, O2 and N2O desorb reversibly with the desorption peak for N2O shifting to lower temperature with increasing exposure, being 102 K for monolayer coverage. NO, on the other hand, decomposes on the Ir(111) surface and its desorption spectrum indicates the existence of three identifiable adsorption states two of which desorb mostly as NO with some dissociation whereas the third state dissociates entirely on heating. The first two states are proposed to correspond to NO which is bridge bonded to three and two atoms, respectively, while the third state corresponds to terminally bonded molecules. © 1990.