Ce添加对Cu-Fe/SiO_2催化合成气制低碳醇性能的影响  

Effect of Cerium Addition on the Catalytic Performance of Cu-Fe/SiO_2 for the Synthesis of Lower Alcohols from Syngas

作　　者：毛东森[1] 郭强胜[1] 俞俊[1] 韩璐蓬[1] 卢冠忠[1] 

机构地区：[1]上海应用技术学院化学与环境工程学院应用催化研究所,上海200235

出　　处：《物理化学学报》2011年第11期2639-2645,共7页Acta Physico-Chimica Sinica

基　　金：上海市科委(08520513600);上海市教委曙光跟踪计划(10GG23);上海市教委重点学科建设(J51503)资助项目~~

摘　　要：采用共浸渍法制备了添加不同Ce含量(相对于SiO_2的摩尔分数为0-20%)的Ce-Cu-Fe/SiO_2催化剂,在连续流动微型固定床反应器中考察了其催化CO加氢合成低碳醇反应的性能,并采用X射线衍射(XRD)、低温N_2吸附、程序升温还原(H_2-TPR)、CO吸附傅里叶变换红外光谱(CO-FTIR)和CO程序升温脱附(CO-TPD)技术对催化剂进行了表征.结果表吸:添加适量的Ce,一方面降低了Cu的晶粒大小,提高了Cu的分散度,进而提高了对CO的吸附能力;另一方面掺入的Ce和Cu之间存在相互作用,提高了CO解离和非解离吸附的能力,从而有利于CH_x的生成和CO的插入反应.上述两方面的共同作用同时提高了Cu-Fe/SiO_3催化剂的活性和醇的选择性.当Ce含量为10%时,在压力为3.0 MPa,温度为250℃,空速为6000 mL·g^(-1)·h^(-1)和H_2/CO摩尔比为2的反应条件下,Ce-Cu-Fe/SiO_2催化剂上醇的时空产率达到121.0 g·kg^(-1)·h^(-1),比未添加Ce的Cu-Fe/SiO_2催化剂的时空产率(58.0 g·kg^(-1)·h^(-1))提高了一倍以上.A series of Ce-Cu-Fe/SiO_2 catalysts with different Ce contents（mole fraction relative to SiO_2, 0-20%） were prepared by co-impregnation and their catalytic performances for CO hydrogenation to lower alcohols were investigated using a continuous flow fixed bed micro-reactor.These catalysts were characterized by X-ray diffraction（XRD）,N_2-adsorption,temperature-programmed reduction of H_2 （H_2-TPR）,Fourier transform infrared of CO adsorption（CO-FTIR）,and temperature-programmed desorption of CO（CO-TPD）.The results showed that the addition of an appropriate amount of Ce decreased the Cu crystal size and promoted the dispersion of Cu,which greatly increased the amount of adsorbed CO.Additionally,the interaction of doped Ce with Cu increased the associative and dissociate adsorption capacity of CO,which is favorable for the formation of CH_x and the insertion reaction of adsorbed CO to CH_x.Both the activity and alcohol selectivity of the Cu-Fe/SiO_2 catalyst increased under the combined effect of the above-mentioned two aspects.At a Ce content of 10%,the space time yield of lower alcohols improved from 58.0 g·kg^（-1）·h^（-1） over the Cu-Fe/SiO_2 catalyst to 121.0 g·kg^（-1）·h^（-1） over the Ce-Cu-Fe/SiO_2 catalyst at 250℃,a pressure of 3.0 MPa,a H_2/CO molar ratio of 2,and gas hourly space velocity of 6000 mL·g^（-1）·h^（-1）.

关 键 词：铈助剂 Cu-Fe/SiO_2催化剂 合成气 催化加氢 低碳醇 

分 类 号：O643.36[理学—物理化学]