Ce–K-promoted Co–Mo/Al2O3 catalysts for the water gas shift reaction

The effect of doping traditional Co–Mo/Al2O3 catalysts with Ce and K on their catalytic activity for the water gas shift reaction in coke oven gas was investigated. Doped Co–Mo/Al2O3 catalysts were prepared by adding different amounts of Ce and K (CeO2, K2O, and CeO2–K2O ∼10 wt%) by a wetness impregnation method and characterized by BET specific surface area measurements and scanning electron microscopy (SEM). The characterization results reveal that CeO2 addition mainly produced an electronic effect and aided to disperse the active ingredient. At the same time, the synergistic effect between Ce and K contributed to the catalytic activity. Activity tests showed that Ce–K-promoted Co–Mo/Al2O3 catalysts exhibited greater activity and selectivity than Co–Mo–Ce/Al2O3 catalysts and Co–Mo–K/Al2O3 catalysts. The maximum promotion of the water gas shift reaction was observed when 3.0 wt% CeO2 and 6.0 wt% K2O were added. Ce–K-promoted Co–Mo/Al2O3 catalysts exhibited higher activity and selectivity than Co–Mo–Ce/Al2O3 catalysts and Co–Mo–K/Al2O3 catalysts. The Ce–K addition increased the maximum CO conversion from 46% at 200°C to 92% at 300°C for Co–Mo/Al2O3-supported catalyst. The addition of CeO2 mainly produces an electronic effect and aids the dispersion of active component. At the same time, the metal–metal interaction between Ce and K produce synergistic effects and resulted in changes in properties of the catalysts. Ce–K bimetallic and geometric effects may be involved, changing catalytic properties of the bimetallic samples. [Display omitted] ► The effect of Ce–K addition on Co–Mo/Al2O3 was studied for WGS reaction. ► Study evidenced that the interaction between Ce and K was dependent on the support. ► Ce3K6 catalyst shows higher CO conversion due to an interaction between Ce and K. ►Co–Mo–Ce3K6/Al2O3 catalyst has a good performance for WGS.