Abstract

CATAL REV.-SCI. ENG., 31(1&2), 1-41 (1989) Structure and Function of the Catalyst and the Promoter in Co-Mo Hydrodesulfurization Catalysts R. PRINS* AND V. H. J. DE BEER Laboratory for Inorganic Chemistry Eindhoven University of Technology P.O. Box 5 13, 5600 MB Eindhoven, The Netherlands G. A. SOMORJAI Materials and Molecular Research Division Lawrence Berkeley Laboratory, and Department of Chemistry University of California Berkeley, California, U.S.A. I. INTRODUCTION ....................... 2 11. STRUCTURE AND COMPOSITION OF THE CATALYST .......................... 3 A. The Mo-S/y-A1203 System ................ 3 B. The Co-Mo-S/y-AI2O3 System ............. 5 *To whom correspondence should be addressed at his present address: Technisch- Chemisches Laboratonurn, 8092 Zurich. Switzerland. Copyright @ 1989 hy Marcel Dekker, Inc. 2 PRINS, DE BEER, AND SOMORJAI 111. MODELS OF THE HDS REACTION MECHANISMS OVER THE M*S/y-A12Os SYSTEM AND EXPERIMENTAL VERIFICATIONS ........... 8 A. Solid-state Model ...................... 8 B. Organometallic Chemistry Models ............ 11 C. Surface Science Model ................... 19 IV. ROLE OF THE COBALT PROMOTER .......... A. Co as a Textural Promoter ................ 25 B. Co Role in Hydrogen Spillover .............. 27 C. Co Role as Bonding Modifier of the Mo Site ...... 28 D. Determination of the Number of Active Sites ...... 30 E. Co