Abstract: V2O5SiO2(VSiO) supported CuNiK2O catalysts for the synthesis of dimethyl carbonate were prepared using isovolumic impregnation. Based on TPR,TPD, IR and microreactor techniques, the effect of K2O on the adsorption and reaction of CO2 and CH3OH on the catalyst were characterized. The results show that addition of K2O exerts obvious influence on the charge distribution of the active sites on CuNi/VSiO catalyst,increases the intensities of CO2 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 CO2 and CH3OH on CuNiK2O/VSiO catalyst are still DMC, H2O, CO and CH2O,and with the addition of K2O, the conversion of reactants rise, but the selectivity of by-products decreases.

Key words: K₂O, Supported Cu-Ni catalyst, Carbon dioxide, Methanol, 　Dimethyl carbonate