【摘要】 用添加表面活性剂的两步沉淀法制备了以蛋壳型纳米空心SiO2为载体的CuO/ZnO催化剂和掺杂Ce的CuO/ZnO催化剂,初步考察了两组催化剂用于一氧化碳加氢合成甲醇的催化性能,并采用TEM,BET,XRD,XPS等方法对催化剂的结构进行了表征.结果表明,以纳米空心SiO2为载体的CuO/ZnO催化剂具有较大的比表面积,活性成分在载体表面分散均匀,粒径在13nm左右.加入掺杂剂Ce能有效提高催化剂的活性和选择性:一方面,Ce可以降低Cu2p3/2和Zn2p3/2的表面结合能,使氧化铜更容易被氢气还原成铜;另一方面,Ce也能增强铜锌之间的相互作用,抑制铜粒子的烧结,改善活性成分的分散.更多还原

【Abstract】 Eggshell-shaped CuO/ZnO/SiO2 and CuO/ZnO/Ce/SiO2 particulate catalysts supported with porous hollow SiO2 nanoparticles were prepared by a two-step precipitation method combined with addition of surfactant. The catalytic performances of the prepared catalysts for methanol synthesis from CO hydrogenation were investigated, and the catalyst structure was characterized by TEM, BET, XRD and XPS techniques. The results showed that the catalysts supported with porous hollow SiO2 nanoparticles had large specific surface areas, and the CuO and ZnO particles with an average size of about 13 nm were well dispersed on the support. The Ce promoter could improve the catalytic activity and the selectivity of methanol significantly, probably by two reasons: (1) Ce could lower the binding energy of Cu 2p3/2 and Zn 2p3/2, thus facilitating the reduction of CuO to Cu by hydrogen, and (2) the presence of Ce might enhance the interaction between Cu and Zn, and hence improved the dispersion of active components by preventing Cu particles from aggregating.更多还原