采用并流共沉淀法制备了不同Cu/Zn摩尔比的CuO/ZnO/Al2O3催化剂,考察了其浆态床CO加氢合成甲醇的催化性能.通过N2吸附-脱附、X射线衍射、程序升温还原及X射线光电子能谱等方法对催化剂表面性质进行了表征.结果表明,催化剂具有体相和表面高分散两种不同还原性质的CuO,表面CuO的含量及其与ZnO的相互作用使催化剂活性增大.当催化剂中Cu/Zn≤1时,随着铜含量的增加,表面高分散的CuO量增加,CuO和ZnO之间相互作用增强,催化剂的活性也随之增大;当催化剂Cu/Zn〉1时,增加的铜量主要体现为体相CuO含量的增加,且ZnO结晶度提高,CuO和ZnO之间的相互作用减弱,催化剂的活性随铜含量增大而减小.
The CuO/ZnO/Al2O3 slurry catalyst was prepared by parallel flow co-precipitation at different Cu/Zn molar ratios and characterized by N2 adsorption-desorption, X-ray diffraction, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. When Cu/Zn≤1, the quantity of highly dispersed copper oxide on the catalyst surface was increased with increasing copper content, which favored the interaction of CuO and ZnO and increased catalyst activity for methanol synthesis. When Cu/Zn〉1, the quantity of bulk copper was increased with increasing copper content, the crystallinity of ZnO was increased, and the interaction of CuO and ZnO was weakened, leading to the decrease in the activity of the CuO/ZnO/Al2O3 catalyst.