Use of supported rhodium and cobalt carbonyls as catalysts for the CO + H2 reaction

The use of cobalt and rhodium catalysts derived from carbonyl clusters and supported on Al2O3, Al2O3–ZnO, ZrO2 and SiO2 for the CO + H2 reaction has been investigated. Only Rh-containing catalysts were active in the formation of oxygenated compounds (essentially ethanol). In all the runs the selectivity to methane plus ethanol was > 90%. The ratios of the rates of ethanol and methane formation or the rate of ethanol formation and the CO reaction reach a maximum when equal amounts of Rh and Co are present on the catalyst surface. Cobalt alone does not form oxygenates, but when mixed with rhodium it increases the selectivity to ethanol.