The effect of potassium-decoration was studied on the activity of water-gas shift （WGS） reaction over the Co-Mo-based catalysts supported on active carbon （AC）, which was prepared by incipient wetness co-impregnat...The effect of potassium-decoration was studied on the activity of water-gas shift （WGS） reaction over the Co-Mo-based catalysts supported on active carbon （AC）, which was prepared by incipient wetness co-impregnation method. The decoration of potassium on active carbon in advance enhances the activities of the CoMo-K/AC catalysts for WGS reaction. Highest activity （about 92% conversion） was obtained at 250 ？ C for the catalyst with an optimum K 2 O/AC weight ratio in the range from 0.12 to 0.15. The catalysts were characterized by TPR and EPR, and the results show that activated carbon decorated with potassium makes Co-Mo species highly dispersed, and thus easily reduced and sulfurized. XRD results show that an appropriate content of potassium-decoration on active carbon supports may favors the formation of highly dispersed Co 9 S 8 -type structures which are situated on the edge or a site in contact with MoS 2 , K-Mo-O-S, Mo-S-K phase. Those active species are responsible for the high activity of CoMo-K/AC catalysts.展开更多
Co-Mo/MgO-Al_(2)O_(3)catalyst was presulfided with ammonium sulfide in aqueous solution and activated with synthesis gas for water gas shift reaction.The assay results indicate that the presulfided Co-Mo/MgO-Al_(2)O_(...Co-Mo/MgO-Al_(2)O_(3)catalyst was presulfided with ammonium sulfide in aqueous solution and activated with synthesis gas for water gas shift reaction.The assay results indicate that the presulfided Co-Mo/MgO-Al_(2)O_(3)catalyst exhibits an excellent catalytic activity and stability.XRD and EPR characterization results show that the O-S exchange might occur during the impregnation,leading to the formation of(NH4)2MoS4(or(NH4)zMoxSy)precursor,which was then thermally decomposed and reduced to MoS2.The higher catalytic performance is attributed to an optimization formation of active Co-Mo sulfides,consisting of well dispersed MoS2 and Co-Mo-S phase due to the redispersion of Co sulfide particles over the edges of newly formed MoS2 crystallites.展开更多
文摘The effect of potassium-decoration was studied on the activity of water-gas shift （WGS） reaction over the Co-Mo-based catalysts supported on active carbon （AC）, which was prepared by incipient wetness co-impregnation method. The decoration of potassium on active carbon in advance enhances the activities of the CoMo-K/AC catalysts for WGS reaction. Highest activity （about 92% conversion） was obtained at 250 ？ C for the catalyst with an optimum K 2 O/AC weight ratio in the range from 0.12 to 0.15. The catalysts were characterized by TPR and EPR, and the results show that activated carbon decorated with potassium makes Co-Mo species highly dispersed, and thus easily reduced and sulfurized. XRD results show that an appropriate content of potassium-decoration on active carbon supports may favors the formation of highly dispersed Co 9 S 8 -type structures which are situated on the edge or a site in contact with MoS 2 , K-Mo-O-S, Mo-S-K phase. Those active species are responsible for the high activity of CoMo-K/AC catalysts.
文摘Co-Mo/MgO-Al_(2)O_(3)catalyst was presulfided with ammonium sulfide in aqueous solution and activated with synthesis gas for water gas shift reaction.The assay results indicate that the presulfided Co-Mo/MgO-Al_(2)O_(3)catalyst exhibits an excellent catalytic activity and stability.XRD and EPR characterization results show that the O-S exchange might occur during the impregnation,leading to the formation of(NH4)2MoS4(or(NH4)zMoxSy)precursor,which was then thermally decomposed and reduced to MoS2.The higher catalytic performance is attributed to an optimization formation of active Co-Mo sulfides,consisting of well dispersed MoS2 and Co-Mo-S phase due to the redispersion of Co sulfide particles over the edges of newly formed MoS2 crystallites.
