不同合成方法制备FeMnK/ZSM-5催化剂结构与催化性能研究

Study on the Catalytic Performance of FeMnK/ZSM-5 Catalysts Prepared by Different Synthesis Methods

以ZSM-5为载体,通过旋蒸法、冷冻干燥法和直接烘干法三种不同的干燥方法制备得到FeMnK/ZSM-5型催化剂.利用N_(2)物理吸附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、NH_(3)/CO程序升温脱附(NH_(3)/CO-TPD)等现代分析手段对所得催化剂进行结构表征.在n(H_(2))/n(CO)=2,反应温度T=320℃,反应压力P=2.5 MPa,反应空速G=1000 h^(-1)的反应条件下,对所得催化剂进行性能评价.结果表明:CO转化率最高可达90.42%,CH_(4)的选择性为13.45%,C_(2-4)^(=)的选择性为40.77%,C_(2-4)^(0)的选择性为6.24%,C_(5)^(+)的选择性为39.54%.综合考虑分析得到,冷冻干燥法所制备的FeMnK/ZSM-5型催化剂在催化合成烯烃方面性能较优.

This article utilized ZSM-5 as a carrier to prepare FeMnK/ZSM-5 catalysts using three different drying methods:rotary evaporation,freeze-drying,and direct drying.The structure of the obtained catalysts was characterized using modern analytical methods including N_(2) physical adsorption(BET),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),and NH₃/CO temperature-programmed desorption(NH_(3)/CO-TPD).The performance of the obtained catalysts was evaluated under the following reaction conditions:n(H_(2))/n(CO)=2,reaction temperature T=320°C,reaction pressure P=2.5 MPa,and reaction space velocity G=1000 h^(-1).The results show that the maximum CO conversion rate reached 90.42%,the selectivity for CH_(4)is 13.45%,the selectivity for C_(2-4)^(=)is 40.77%,the selectivity for C_(2-4)^(0) is 6.24%,and the selectivity for C_(5)^(+)is 39.54%.After comprehensive consideration and analysis,it can be concluded that the FeMnK/ZSM-5 catalyst prepared using the freeze-drying method exhibits superior performance in the catalytic synthesis of olefins.