The performance of C-2 oxygenates synthesis from syngas over Rh-Mn-Li-Fe/SiO2 catalysts with various Rh loadings

The promotion effect of additives on Rh-Mn-Li-Fe/SiO2 catalyst was investigated by means of an in-situ FTIR technique. IR results suggested that the additives Fe, Mn, and Li might be in close contact with Rh, and form new active sites, which promoted CO activation over Rh surface and favored the formation of C-2-oxygenated intermediates. The catalysts with rhodium loading of 1.0-5.0 wt % were tested by CO hydrogenation to find the optimized rhodium loading. The results showed that the high-rhodium-loading catalysts exhibited high activity and selectivity toward C-2 oxygenates at low temperature, but the selectivity was very sensitive to reaction temperature, low-rhodium-loading catalysts showed low activity, while the selectivity was not so sensitive to reaction temperature, therefore high space time yield (STY) of C-2 oxygenates can be obtained by increasing the reaction temperature. Among the catalysts investigated, the 1.5 wt % rhodium catalyst exhibited the highest selectivity and relative higher rhodium efficiency for the synthesis of C-2 oxygenates.