THE ISOLATION OF DISPERSION PHASE EXAFS AND COORDINATION OF NI IONS ON THE SURFACE OF NIO GAMMA-AL2O3 SYSTEM/

The coordination structure of dispersed phase in the NiO/gamma-Al2O3 s ystem has been isolated by applying the EXAFS principle of mixed phase s. Both Ni-O and Ni-Ni coordination states vary with the Ni content in the sample, but once the dispersion amount of NiO reaches the maximum --threshold, in the coordination curve an inflection point appears and the coordination of dispersed phase gets stable. The results show tha t the NiO dispersed phase has its own characteristic coordination stru cture. On the basis of the results, a monolayer dispersion model has b een suggested.