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Rh-V/SiO_2 catalyst for the synthesis of C_2-oxygenates from syngashas been studied by means of reaction evaluation,TEM,TPR,TPD and FT-IRspectroscopy.It has been found when vanadium promoter was incorporated intothe Rh/SiO_2 catalyst,the rate of C_2-oxygenate formation was increased bymore than an order of magnitude,and the selectivity was improved from ca.30% to more than 70%,based on carbon efficiency.The vanadium ion inRh-V/SiO_2 catalysts can be readily reduced to lower valence states,and the ca-pacity of hydrogen adsorption remarkably enhanced for the catalyst.Further-more,for the Rh-V/SiO_2 catalyst cooled in H_2 to room temperature after reduc-tion,the vibration frequencies of CO adsorbed on it exhibit large red-shifts of40-70cm~(-1) for bridged CO and of ca.10cm~(-1) for linear CO,as comparedwith those of the unpromoted Rh/SiO_2 catalyst and of the promoted Rh-V/SiO_2 catalyst outgassed at 573 K after reduction by hydrogen.A model of COactivation by metal rhodjum,lower valence vanadium and activa
Rh-V / SiO 2 catalyst for the synthesis of C 2 -oxyates from syngashas been studied by means of reaction evaluation, TEM, TPR, TPD and FT-IR spectroscopy. It has been found when vanadium promoter was incorporated intothe Rh / SiO 2 catalyst, the rate of C 2 -oxygen formation was increased bymore than one order of magnitude, and the selectivity was improved from ca. 30% to more than 70%, based on carbon efficiency. The vanadium ion in Rh-V / SiO 2 catalysts could be significantly reduced to lower valence states, and the ca-pacity of hydrogen adsorption remarkably enhanced for the catalyst. Future-more, for the Rh-V / SiO_2 catalyst cooled in H_2 to room temperature after reduc tion, the vibration frequencies of CO adsorbed on it exhibit large red-shifts of 40-70 cm -1 for bridged CO and of ca.10 cm -1 for linear CO, as compared with those of the unpromoted Rh / SiO 2 catalyst and of the promoted Rh-V / SiO 2 catalyst outgassed at 573 K after reduction by hydrogen. A model of COactivation by metal rhodjum, lower valence vanadium and activa