镧助剂对Fe/ZrO_2催化剂结构及F-T反应性能的影响

INFLUENCE OF LANTHANUM ON THE STRUCTURE AND CATALYTIC PERFORMANCE OF Fe/ZrO 2 CATALYSTS FOR CO HYDROGENATION

用ＸＲＤ，Ｍｏｓｓｂａｕｅｒ谱，ＴＰＲ，ＣＯ－ＴＰＤ和ＣＯ加氢反应性能测试等手段研究了镧助剂对Ｆｅ／ＺｒＯ２催化剂结构及Ｆ－Ｔ合成催化性能的影响．结果表明，不同的制备方法明显影响催化剂的结构及反应性能．镧助剂以Ｌａ２Ｏ３形式存在时，催化剂上甲烷选择性降低，烯烃选择性提高；镧助剂以ＬａＦｅＯ３形式存在时，催化剂的催化活性大大提高，但同时甲烷选择性上升，烯烃选择性下降．

La promoted Fe/ZrO 2 catalysts were prepared by different impregnation methods. The structure, reduction behavior, CO desorption behavior and catalytic performance of the catalysts were studied by XRD, Mssbauer spectroscopy, TPR, CO TPD and CO hydrogenation. It is shown that the impregnation sequence seriously affects the characteristic of the catalysts. For Fe La samples prepared by co impregnation method, perovskite type LaFeO 3 phase was formed in the preparation process. For Fe/La sample prepared by sequential impregnation method, La 3+ cations formed La 2O 3. CO hydrogenation results show that the catalytic activity is much higher when lanthanum promoter exists in perovskite type LaFeO 3 state than in La 2O 3 state.