Highly dispersed cobalt in CuCo/SiO2 cluster-derived catalyst

A silica-supported CuCo catalyst has been prepared by anchoring a Cu-Co bim etallic complex. Evolution of the species under vacuum and CO treatments ha s been followed by in situ FTIR. A breakdown of the initial complex with CO at 373 K gives [Co(CO)(4)](-). After total decarbonylation, a subsequent C O treatment followed by FTIR indicates the presence of metallic Cu and very small particles of cobalt. The catalyst obtained after an H-2-treatment at 473 K has been characterized by XRD, TEM and XPS techniques. The presence of large Cu particles and highly-dispersed subnanometric cobalt particles i s inferred. Coordination of CO on these very small particles of metallic co balt could give Co-4(CO)(12). Catalytic behaviour in the hydroformylation o f ethylene and in the hydrogenation of CO is related to the highly disperse d cobalt, which probably interacts with Cu. An easy CO insertion into a met al-alkyl bond is favoured over this CuCo catalyst. (C) 1999 Elsevier Scienc e B.V. All rights reserved.