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The activation of adsorbed CO is an important step in CO hydrogenation.The results from TPSR of pre-adsorbed CO with H_2 and syngas suggested that the presence of H_2 increased the amount of CO adsorption and accelerated CO dissocia- tion.The H_2 was adsorbed first,and activated to form H~* over metal sites,then reacted with carbonaceous species.The oxygen species for CO_2 formation in the presence of hydrogen was mostly OH~*,which reacted with adsorbed CO subsequently via CO~*+OH~*→CO_2~*+H~*;however,the direct CO dissociation was not excluded in CO hydrogenation.The dissociation of C-O bond in the presence of H_2 proceeded by a concerted mechanism,which assisted the Boudourd reaction of adsorbed CO on the surface via CO~*+2H~*→CH~*+OH~*.The formation of the surface species(CH)from adsorbed CO proceeded as indicated with the participation of surface hydrogen,was favored in the initial step of the Fischer-Tropsch synthesis.
The activation of adsorbed CO is an important step in CO hydrogenation. The results from TPSR of pre-adsorbed CO with H_2 and syngas suggested that the presence of H_2 increased the amount of CO adsorption and accelerated CO dissociation. The H_2 was adsorbed first , and activated to form H ~ * over metal sites, then reacted with carbonaceous species. The oxygen species for CO 2 formation in the presence of hydrogen was mostly OH ~ *, which reacted with adsorbed CO via via CO ~ * + OH ~ * → CO_2 ~ * + H ~ *; however, the direct CO dissociation was not excluded in CO hydrogenation. The dissociation of CO bond in the presence of H_2 proceeded by a concerted mechanism, which assisted the Boudourd reaction of adsorbed CO on the surface via CO ~ * + 2H ~ * → CH ~ * + OH ~ *. The formation of the surface species (CH) from adsorbed CO proceeded as indicated with the participation of surface hydrogen, was favored in the initial step of the Fischer-Tropsch synthesis.