掺杂物对负载型ZrO_2/Al_2O_3的催化性能的影响  

The Effect of Oxides Doping on the Property of ZrO_2/Al_2O_3 Catalyst

作　　者：刘金聚[1] 李凝[1] 范细林 陈俭省[1] 

机构地区：[1]桂林工学院材料与化学工程系,广西桂林541004 [2]湖南新宁二中,湖南新宁422700

出　　处：《分子催化》2009年第5期454-458,共5页Journal of Molecular Catalysis(China)

基　　金：广西科学基金项目(桂科自0728217);广西研究生教育创新计划资助项目(2008105960817M09)

摘　　要：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.Impregnation-precipitation method was applied to prepare the supported ZrO/Al2O3 and ZrO2-（ MgO, K2O、 CeO2 、 La2O3 ）/Al2O3. Crystalline structures, surface area, pore diameter distribution and acid-base properties of the catalysts were characterized by XRD, BET, In-situ IR, and TPD. The Synthesis of dimethyl carbonate （DMC） from carbon dioxide and methanol was chosen to investigated the catalytic properties of the catalysts. The results indicated that the doping oxides blocked the integrating of the ZrO2 effectively. The grain size of the ZrO2 was decreased and the surface area of the catalysts was increased. The existence of the CeO2 increased the number of base sites, and the existence of the La2O3 increased the number of acid sites. In-situ IR indicated that dissociative adsorption of methanol occurred on the surface of ZrO2- （ CeO2 , La2O3 ）/Al2O3, while carbon dioxide adsorption showed the formation of monodentate carbonate species on the surface of all catalysts. The ZrO2-（ CeO2 , La/O3 ）/Al2O3 performed higher activity and selectivity in the synthesis of dimethyl carbonate from carbon dioxide and methanol.

关 键 词：掺杂氧化物 氧化锆 碳酸二甲酯 

分 类 号：O643.3[理学—物理化学]