RUTHENIUM PROMOTION OF CO AL2O3 FISCHER-TROPSCH CATALYSTS/

The effect of Ru addition upon catalyst characteristics and performanc e in Fischer-Tropsch synthesis was investigated using a series of diff erently prepared, Ru-promoted Co/Al2O3 catalysts. Ru promotion facilit ated reduction of Co/Al2O3 leading to catalysts with higher reducibili ties. Parallel to this effect, the number of reduced metal atoms expos ed on the surface increased for the Ru-promoted catalysts. Ru-promoted catalysts showed an increase in CO hydrogenation activity; however, c onstant turnover frequencies for promoted and unpromoted catalysts sug gest that the increase in the number of metal surface atoms caused the activity enhancement. Isotopic transient kinetic analysis of CO hydro genation under methanation conditions gave identical results, Catalyst s prepared by a co impregnation technique, avoiding chloride salts, ap pear to be optimal for the production of high-molecular-weight hydroca rbons. (C) 1996 Academic Press, Inc.