Model studies of the interaction of CO and H 2 on transition metals : II. On the role of chemisorption complexes in primary reactions

Abstract

The binding energies and electronic structures of the chemisorption complexes of CO-H 2 mixtures on iron, cobalt and nickel were calculated by means of the extended Hückel theory (EHT) within a simple chemisorption model, followed by a Mulliken [ J. Chem. Phys. 23, 1833 (1965)] population analysis. Complexes of the Anderson type containing oxygen seem to be stable on iron and cobalt only, whereas a complex on nickel is probably of methylene type. Using the iron complex as an example, a special catalytic activity for chain propagation on (111)-surface clusters can be deduced from the geometrical and electronic structure of the complex. A comparison of the calculated structures of the iron, cobalt and nickel complexes and their probable chemical properties leads to some meaningful reflections on reaction paths during synthesis.