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V2O5- SiO_2(VSiO) supported Cu- Ni- K_2O catalysts for the synthesis of dimethyl carbonate were prepared using isovolumic impregnation. Based on TPR,TPD, IR and micro- reactor techniques, the effect of K_2O on the adsorption and reaction of CO_2 and CH_3OH on the catalyst were characterized. The results show that addition of K_2O exerts obvious influence on the charge distribution of the active sites on Cu- Ni/VSiO catalyst,increases the intensities of CO_2 horizontal adsorption state, while that of the dissociation state of methanol descends. When the ratio of K is above 15％ , K2CO3 is formed on the catalyst. Moreover,the main reaction products of CO_2 and CH_3OH on Cu- Ni- K_2O/VSiO catalyst are still DMC, H_2O, CO and CH_2O,and with the addition of K_2O, the conversion of reactants rise, but the selectivity of by- products decreases.
V2O5- SiO 2 (VSiO) supported Cu-Ni-K 2 O catalysts for the synthesis of dimethyl carbonate were prepared using isovolumic impregnation. Based on TPR, TPD, IR and micro-reactor techniques, the effect of K 2 O on the adsorption and reaction of CO 2 and CH 3 OH on the catalyst were characterized. The results show that addition of K 2 O exerts obviously influence on the charge distribution of the active sites on Cu-Ni / VSiO catalyst, increases the intensities of CO 2 horizontal adsorption state, while that of the dissociation state of methanol Moreover, the main reaction products of CO_2 and CH_3OH on Cu-Ni-K_2O / VSiO catalysts are still DMC, H_2O, CO and CH_2O, and with the addition of K_2O, the conversion of reactants rise, but the selectivity of by- products decreases.