碱金属和稀土金属对CuFe_(8)-LDO催化剂的CO_(2)加氢反应性能的影响

Effects of Alkali and Rare Earth Metals on The Performance of CuFe_(8)-LDO Catalysts for CO_(2)Hydrogenation Reaction

研究了碱金属元素Na、K和稀土金属元素La、Ce、Y对铜铁层状双金属氧化物催化剂(CuFe_(8)-LDO)的CO_(2)加氢反应性能影响,采用XRD、SEM-EDS、低温N 2吸附-脱附、H 2-TPR、CO_(2)-TPD等方法表征了催化剂的结构和物化性质,在此基础上结合其CO_(2)加氢反应性能,研究了构效关系。实验结果表明,碱金属元素Na、K改性能够促进催化剂的还原,改变其对CO_(2)的吸附强度,从而提高了CO_(2)加氢反应活性。其中,Na/CuFe_(8)-LDO催化剂更有利于C 5+烃类的生成,K/CuFe_(8)-LDO催化剂更有利于C 2~C 4烃类的生成。稀土金属元素La、Ce、Y的加入不利于提高催化剂的C 2+烃类选择性,Y/CuFe_(8)-LDO催化剂的CO_(2)加氢反应活性略有增加。

The effect of modifications of copper-iron layered bimetallic oxide catalysts(CuFe_(8)-LDO)by alkali metal elements(Na and K)and rare earth metal elements(La,Ce,and Y)on their CO_(2)hydrogenation performance were investigated.The structures and physicochemical properties of the catalysts were characterized by XRD,SEM-EDS,low temperature N_(2)adsorption-desorption,H 2-TPR,and CO_(2)-TPD.On this basis,the structure-activity relationships were studied in conjunction with their CO_(2)hydrogenation reaction performance.The results showed that the modification with alkali metal elements(Na and K)promoted the reduction of the catalyst and changed its adsorption strength of CO_(2),thus improving its CO_(2)hydrogenation reaction activity.Among them,the Na/CuFe_(8)-LDO catalyst was more favorable to the formation of C 5+hydrocarbons,and the K/CuFe_(8)-LDO catalyst was more favorable to the formation of C_(2)~C_(4)hydrocarbons.The addition of rare earth metal elements(La,Ce,and Y)was not favorable to improve the C_(2)+hydrocarbon selectivity of the catalysts,while only the CO_(2)hydrogenation reaction activity of the Y/CuFe_(8)-LDO catalyst was slightly increased.