Effect of Vanadium Promotion on Activated Carbon-Supported Cobalt Catalysts in Fischer–Tropsch Synthesis

Abstract

The effect of vanadium promotion on activated carbon (AC)-supported cobalt catalysts in Fischer-Tropsch synthesis has been studied by means of XRD, TPR, CO-TPD, H 2 -TPSR of chemisorbed CO and F-T reaction. It was found that the CO conversion could be significantly increased from 38.9 to 87.4% when 4 wt.% V was added into Co/AC catalyst. Small amount of vanadium promoter could improve the selectivity toward C 10 -C 20 fraction and suppress the formation of light hydrocarbon. The results of CO-TPD and H 2 -TPSR of adsorbed CO showed that the addition of vanadium increased the concentration of surface-active carbon species by enhancing CO dissociation and further improved the selectivity of long chain hydrocarbons. However, excess of vanadium increased methane selectivity and decreased C þ 5 selectivity.

Fischer–Tropsch Synthesis over Ordered Mesoporous Carbon Supported Cobalt Catalysts: The Role of Amount of Carbon Precursor in Catalytic Performance

“…When the support is switched from mesoporous carbon to mesoporous silica, the corresponding active phase also transforms from CoO to Co 3 O 4 indicating the argon treatment with poor contribution to generate CoO phase. In a sense, the results of MC supported catalysts might involve the participation of certain groups on the surface of mesoporous carbon as a reducing agent to induce reduction of Co 3 O 4 to CoO in accordance with the previous result of activated carbon supported cobalt catalyst [25]. The higher the FA amount used in the preparation is, the stronger the XRD intensity of CoO in the resulting argon-treated catalyst is, and the narrower the FWHM of CoO diffraction peak is, the larger the formation of crystallites on the surface of supports is.…”

Effects of impregnation strategy on structure and performance of bimetallic CoFe/AC catalysts for higher alcohols synthesis from syngas

“…The desorption peak of CO at about 400 K is due to desorption of CO adsorbed on Co 2+ sites [51]. The peak appeared in high temperature at around 1100 K might be assigned to the decomposition of organic species on surface of activated carbon [52]. The peak at 700 K was ascribed to desorption of a weakly adsorbed CO, while the other two peaks situated between 800 K and 1000 K would arise from a strongly adsorbed CO [53,54].…”

Fischer‐Tropsch Catalysts for the Biomass‐to‐Liquid (BTL)‐Process

“…1). These oxides may cover the catalytically active cobalt metal surface [71,[75][76][77][80][81][82] resulting in a decrease in the total metal surface area. The coverage of metallic cobalt crystallites with these oxides may result in a chemical promotion of the active metal as visualized, e.g.…”

“…The coverage of metallic cobalt crystallites with these oxides may result in a chemical promotion of the active metal as visualized, e.g. using CO-TPD [75,78], XPS [75], and transient kinetic studies [71]. This may lead to higher turn-over frequencies, but will only result in a higher catalytic activity if the increase in the turn-over frequency is not off-set by the decrease in the active metal surface area with the covering metal oxide.…”