Study of CO Hydrogenation over Cobalt-based Catalysts: Synergistic Effect

A series of cobalt-based catalysts were prepared using γ-Al2O3 as a support and cerium/zirconium mixed oxides as promoters, with varying Ce/Zr molar ratios. The 15Co/γ-Al2O3, 15Co/3Zr/γAl2O3, 15Co/3Ce/γ-Al2O3 and 15Co/1.5Zr/1.5Ce/γ-Al2O3 were synthesized using the wet impregnation method. BET, TGA, FE-SEM, XRD, H2-TPR, and ICP techniques were used to determine the characteristics of the prepared catalysts. The findings showed that the catalyst (15Co/1.5Zr/1.5Ce/γ-Al2O3) with double promotion exceeded the performance of other catalysts, indicating notable synergistic effects. These effects are expected to play a crucial role in reducing side reactions that affect selectivity towards higher hydrocarbons. The 15Co/1.5Zr/1.5Ce/γ Al2O3 catalyst demonstrated enhanced stability and reduced degradation during prolonged operation, resulting in higher CO conversion and effective suppression of excessive carbon chain growth. All prepared catalysts were tested in a fixed-bed reactor under a pressure of 27 bar, a temperature of 220 °C, and an H2/CO ratio of 2. The results showed that the doubly-promoted catalyst achieved superior performance, with CO conversion, C5+ selectivity, and yield reaching 50.4 ± 1.5%, 82.3 ± 0.9%, and 41.5 ± 0.8%, respectively, compared to the other catalysts. In conclusion, these findings confirm the substantial influence of Zr and Ce promoters on the performance of Co-based catalysts during the Fischer-Tropsch synthesis reaction.