ELECTRONIC INTERACTION OF NI PARTICLES WITH TIO2 AND SIO2

Ni2p3/2 BE shifts have been observed for Ni/SiO2 catalysts and Ni evaporated on SiO2 and TiO2 depending on the metal particle sizes. For Ni/TiO2 catalysts and Ni evaporated on TiO2 and then heated in H2 at 773 K a constant BE value was always obtained whatever the size of the metal particles. In this case it was found that the intensity of the satellite at BE higher than the main Ni2p3/2 peak is smaller than in Ni/SiO2 and in a Ni foil. These results have been interpreted as a consequence of electronic interactions between the Ni particles and the reduced TiO2 support. Parallel studies with Ni evaporated on a Ti foil and TiO(x) (x = 1.6) substrates confirm this interpretation.