Fischer–Tropsch Synthesis Over Rhodium-Promoted Co/SiO2 Catalysts

Supported cobalt catalysts have been extensively studied for Fischer-Tropsch synthesis (FTS) because of their high activity and selectivity for linear hydrocarbons. The promoting effects of the addition of a second metal to supported cobalt catalysts have been reported in numerous studies. Ru, Re, Pt, and Pd are among the most studied promoters; on the other hand, there have been very limited studies of Rh-Co bimetallic systems. In this work, we report the promoting effect of Rh on silica-supported cobalt catalysts, as well as the results on Ag-Co and Au-Co bimetallic catalysts. Both Au and Rh showed a promoting effect on the FT activity, whereas the addition of Ag decreased the activity. The addition of a small amount of Rh (0.1–0.5 wt%) increased the CO conversion by 50%, while the selectivity was not affected. The deactivated Rh-Co catalysts can be completely regenerated by reduction or by oxidation/reduction treatments. The promoting effect of Rh on Co/SiO2 was studied by XRD, TEM-EDS and TPR/TPO.