Li助剂对Co/AC催化剂上CO加氢制直链混合伯醇反应性能的影响

Effects of Li Promoter on the Performance of Co/AC Catalysts for CO Hydrogenation to Mixed Linear α-Alcohols

采用CO加氢反应、X射线衍射、程序升温还原和CO程序升温脱附等技术研究了Li助剂对活性炭负载的Co催化剂(Co/AC)上CO加氢反应性能的影响.结果表明,Li的添加抑制了气态烃的生成,提高了C5+和直链混合伯醇的选择性,但催化剂活性下降.这可能源于Li的加入抑制了Co2+物种的还原,降低了反应速控步骤——强吸附CO的解离能力.另外,Li也促进了Co2C物种的生成,使得产物中混合醇的比例增加.

The effect of Li promoter on the catalytic performance of the activated carbon（AC） supported cobalt catalysts（Co/AC） for CO hydrogenation was investigated by means of CO hydrogenation,X-ray diffraction（XRD）,temperature-programmed reduction（H2-TPR）,and temperature-programmed desorption of adsorbed CO（CO-TPD）.The results showed that the addition of Li significantly suppressed the formation of gaseous hydrocarbons and remarkably improved the selectivities for higher hydrocarbons（C5＋） and mixed linear α-alcohols（C1-C18） of CO hydrogenation over the Co/AC catalyst.However,the activity of CO hydrogenation decreased gradually with the increase of Li loading in the Co-based catalyst.H2-TPR and CO-TPD results illuminated that the existence of Li decreased the reducibility of Co2＋ and the ability of CO dissociation,which was the rate-determining step.XRD results indicated that the existence of Li promoter enhanced the formation of Co2C species.