【摘要】 用X-光电子能谱(XPS)考察了助剂La、K、V对共沉淀Fe-Mn催化剂表相组成的影响。测试结果表明:La、K对催化剂有供电子效应,而V却有吸电子效应;经还原及FT合成反应后,助剂La、K向催化剂表面发生了迁移,同时由于La、K的存在使催化剂表相碳原子的浓度增加;助剂V则呈现出与La、K相反的倾向。更多还原

【Abstract】 The effect of promoters, such as lanthanum, potassium and vanadium, on the surface composition of coprecipitated iron-manganese FT catalyst has been investigated with X-ray photoelectron Spectroscopy （XPS）. It has been found that the surface of the calcined Fe-Mn catalyst is composed of (Fe_1-xMn_x)₂O₃ and FeOOH. After FT synthesis, metal carbides have been detected on the catalyst surface. The addition of either lanthanum or potassium can decrease the electron binding energy of Fe_2p, i. e. lanthanum and potassium have the electron-drawing effect. During FT synthesis, lanthanum can inhibit the deposition of graphite but promote the formation of carbide, while potassium can accelerate the deposition of graphite. In case of vanadium, formation of both graphite and carbide can be suppressed.更多还原