Effects of dispersion and support on adsorption, catalytic and electronic properties of cobalt/alumina Co hydrogenation catalysts. Final progress report, August 1, 1987--July 31, 1990

摘要

An investigation of the effects of surface structure, dispersion, and support on the adsorption, catalytic, and electronic properties of cobalt/alumina is described, the objectives of which were to determine (1) the effects of surface structure and metal dispersion on the adsorption and catalytic properties of cobalt and (2) the effects of direct electronic interactions between metal clusters and support, on the adsorption, catalytic and electronic properties of cobalt supported on alumina. Effects of surface structure and dispersion on the adsorption, activity/selectivity, and electronic properties of Co/W single crystal surfaces and alumina-supported cobalt were investigated in a surface investigation, lab reactor studies, TPD/TPSR studies, and a Moessbauer spectroscopy study. The structure, stability, surface electronic properties, and chemisorptive properties of vapor-deposited cobalt overlayers (0-4 ML) on W(110) and W(100) were studied by Auger electron spectroscopy, low energy electron diffraction, work function changes, and temperature programmed desorption (TPD) of cobalt, hydrogen, and carbon monoxide. The CO chemisorptive properties of the two cobalt overlayers are quite different, CO adsorption being dissociative on the W(100) surface and nondissociative on the W(110) surface; comparison of the results with those for Ni/W(100) indicate that Co/W(100) dissociates CO as a result of electronic interaction with the tungsten substrate.