Promotional Influence of Hydroxyl Complexing Agent on Ethanol Synthesis from Syngas Over CuZnAl Catalysts Without Other Metal Promoters

摘要

Ternary CuZnAl catalysts promoted with three kinds of hydroxyl complexing agents were prepared by a complete liquid-phase method and tested for ethanol synthesis from syngas in a slurry bed reactor. The catalysts were characterized by XRD, H-2-TPR, NH3-TPD, N-2 adsorption, XPS and TEM techniques. Activity results showed that ethanol selectivity enhanced significantly after the addition of hydroxyl complexing agents. Overall, the catalyst promoted by ethanolamine exhibited the best catalytic performance, with the concentration of ethanol and higher alcohols in the total alcohols reached up to 56.5% and 75.1%, respectively. The addition of hydroxyl complexing agents caused the reduction temperature of Cu+ shifted to be higher and the amount of weak acid sites to be decreased. It also favored the formation of AlOOH and Cu particles with larger particle size. These factors together contributed to the remarkable selectivity of ethanol and higher alcohols.