浆态床合成二甲醚用CuZnAlSi催化剂的完全液相法制备及表征

摘要

采用完全液相法制备了不同SiO_2含量的二甲醚(DME)合成CuZnAlSi双功能催化剂,并在浆态床反应器中评价其催化反应活性,通过in-situ XPS、XRD、BET、NH_3-TPD等方法对其物理化学性能进行研究.结果表明,CuZnAl催化剂中加入SiO_2组分,能够促进活性组分Cu的分散,并通过与AlOOH的作用调变催化剂的孔结构和表面酸性,从而提高催化剂在DME合成反应中的活性.准原位 XPS表征结果显示,还原后的催化剂表面Cu0和ZnO共同构成DME合成反应中的甲醇合成活性中心.SiO_2的加入可能导致Cu、Zn和Al组分间的相互作用减弱,催化剂稳定性降低.%A series of CuZnAlSi bifunctional catalysts with different SiO_2 contents were prepared by a complete liquid phase method, and the catalysts were characterized by using in-situ XPS, XRD, BET and NH_3-TPD. The catalytic performance was evaluated in a slurry reactor. Based on these results, it was deduced that SiO_2 in the CuZnAlSi catalyst could interact with A1OOH resulting in the change of some physicochemical properties, such as the pore structure and surface acidity, thus the catalytic activity for DME synthesis has got improved. It was found from the in-situ XPS characterization that the surface active species for the methanol synthesis in the process of DME production is composed by the reduced Cu~0 species and ZnO. However, the stability of the catalyst decreased owing to the introduction of SiO_2, which may due to a lower interaction among the components of Cu, Zn and Al.