MOLECULAR-ORBITAL CALCULATIONS FOR IRON CATALYSTS

To elucidate the possible catalytic action of iron-based direct coal l iquefaction (DCL) catalysts, we model various surfaces of FeS and Fe-( 1-x)S-y, clusters with a molecular orbital approach. We have studied t he adsorption of toluene and l-methylnaphthalene at various Sites on F eS and related defect clusters and have calculated bond-breaking energ ies of the aromatic-aliphatic linkage. A preliminary explanation of th e catalytic activity of FeS is the donation of electrons to the iron s urface by the adsorbate, followed by a subsequent decrease in the bond -breaking energies as compared to the nonchemisorbed species.