STRONG METAL-SUPPORT INTERACTION (SMSI) STATE IN TITANIA-SUPPORTED IRON CATALYSTS - EHMO MODEL CLUSTER CALCULATIONS

The phenomenon of strong metal support interaction (SMSI) has been explained on the basis of clusters of metal particles being formed on the surface of the support which could account for the reduction in chemisorption capacity after inducement of SMSI state on reduction at high temperatures. Models have been chosen to represent the encapsulation state which could also account for the reduction in chemisorption capacity. The increased hydrogenation activity of these systems is explained on the basis of the orbitals of the clusters which interact suitably with the orbitals of CO in such a manner as to facilitate its dissociation.