PROPERTIES OF SILICA-SUPPORTED CU CO BIMETALLIC CATALYSTS IN THE SYNTHESIS OF HIGHER ALCOHOLS

Silica-supported copper/cobalt catalysts have been prepared in such a way as to generate bimetallic copper/cobalt particles. The existence of alloy particles has been demonstrated by measuring the variation in the activity for the hydrogenolysis of propane, by temperature-programmed reduction, and by high-resolution analytical electron microscopy. When the catalysts were tested in a CO/CO2/H2 mixture at high pressure it was found that the bimetallic particles had very little activity for the synthesis of oxygenates. The only catalyst which produced a significant amount of higher oxygenates was a pure cobalt on silica catalyst which contained some unreduced cobalt ions. Although in the IFP (Institut Français du Pétrole) catalysts, copper is believed to be a key component, it appears from our work that bimetallic particles of copper and cobalt are not necessary for the synthesis of higher alcohols. It seems that the key components of a higher alcohol synthesis catalyst are metallic cobalt and unreduced cobalt ions. Some possible roles for copper in such catalysts are discussed. © 1990.