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用浸渍-沉淀法分别制备了负载型ZrO2/Al2O3和ZrO2-(MgO、K2O、CeO2、La2O3)/Al2O3催化剂.用XRD、BET、TPD对催化剂的晶相结构、比表面积、孔径分布、表面酸碱性等进行了表征;同时以CO2和CH3OH为探针用原位红外对催化剂的吸附行为进行研究.结果表明,掺杂氧化物有效的阻止ZrO2晶粒的团聚,并提高了催化剂的比表面积和平均孔径;CeO2的添加有利于碱性中心数的增多,La2O3有利于酸性中心数的提高.原位红外结果表明CH3OH能在ZrO2-(CeO2、La2O3)/Al2O3催化剂表面发生解离吸附,而CO2在催化剂表面均出现单齿态吸附.CO2和CH3OH在常压下直接合成碳酸二甲酯(DMC)反应中ZrO2-(CeO2、La2O3)/Al2O3催化剂表现出较好的催化活性和选择性.
The supported ZrO2 / Al2O3 and ZrO2- (MgO, K2O, CeO2, La2O3) / Al2O3 catalysts were prepared by impregnation-precipitation method respectively.The crystal structure, specific surface area, pore size distribution, surface acidity Basicity and so on.The adsorption behavior of the catalyst was investigated by in situ infrared with CO 2 and CH 3 OH as the probes.The results showed that the doped oxide effectively prevented the agglomeration of the ZrO 2 grains and increased the specific surface area of the catalyst And average pore size.The addition of CeO2 was beneficial to the increase of the number of basic centers and the increase of the number of acidic sites by La2O3.The in situ IR results showed that CH3OH could dissociate and adsorb on the surface of ZrO2- (CeO2, La2O3) / Al2O3 catalyst The monodisperse adsorption of CO2 on the surface of the catalyst showed that the catalytic activity and selectivity of ZrO2- (CeO2, La2O3) / Al2O3 catalysts for the direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH at atmospheric pressure were high.