Ce改性对CuZnAl催化剂催化合成气制低碳醇的影响

摘要

采用完全液相法制备了一系列Ce改性的CuZnAl催化剂,利用粉末X射线衍射(XRD)、H2程序升温还原(H2-TPR)、氨气吸附-脱附(NH3-TPD-MS)和N2物理吸附-脱附法等技术对其进行表征,并在浆态床反应器上考察了其在合成气制低碳醇反应中的性能.结果显示:Ce的加入有助于Cu物种的分散,减小催化剂中Cu0颗粒大小,同时也会改变Cu、Zn和Al物种之间的作用关系、减小催化剂表面的弱酸量及增加催化剂的比表面积;CuZnAl催化剂加入Ce有助于抑制水煤气变换反应,减少CO2的生成,但同时会降低高级醇(C2+OH)的选择性.%A series of Ce modified CuZnAl catalysts were prepared by the complete liquid-phase method, and characterized by XRD, H2-TPR, NH3-TPD-MS and N2 adsorption-desorpotion. The catalytic performances of the catalysts for the synthesis of higher alcohols from syngas were investigated in a slurry reactor. The results showed that doping with Ce was beneficial to improve the dispersion of Cu species and decreased the size of Cu0 particles. In addition, it would change the interaction among Cu, Zn and Al species, and also decrease the amount of weak acid on catalysts surface and increase the specific surface area of catalysts. Adding Ce into CuZnAl catalyst helped to inhibit the water gas shift reaction and reduce the formation of CO2, but also decrease the selectivity of higher alcohols (C2+OH).