氧化铝基载体组成对钴基催化剂结构和费-托合成催化性能的影响

以γ-Al2O3为原料制备Ni-γ-Al2O3、Zn-γ-Al2O3和Al2O3载体,并采用等容浸渍法制备了钴基费-托合成用催化剂。结果表明:高温焙烧使氧化铝晶型和孔结构发生较大变化;镍添加后在载体表面形成高分散的氧化镍物种;而锌添加后与载体发生反应生成了铝酸锌;负载型催化剂中,四氧化三钴粒径大小主要取决于载体孔结构。CoPt/γ-Al2O3、CoPt/Zn-γ-Al2O3、CoPt/Ni-γ-Al2O3具有相近的费-托合成催化性能,而CoPt/Al2O3呈现出最高的催化活性和最低的甲烷选择性。表明,钴物种粒径和载体结构是影响催化剂费-托合成催化性能的主要因素。

Effect of Al2 O3-Based Support Composition on the Structure and Performance of Cobalt-Based Catalysts in Fischer-Tropsch Synthesis

Three materials （Ni-γ-Al2 O3 ,Zn-γ-Al2 O3 and Al2 O3 ）were prepared fromγ-Al2 O3 and used as supports for cobalt-based Fischer-Tropsch catalysts.Addition of Ni toγ-Al2 O3 resulted in highly dispersed NiO,while addition of ZnO led to the formation of ZnAl2 O4 .In the supported catalysts,cobalt particle size was mostly determined by support pore structure.It was found that CoPt/γ-Al2 O3 ,CoPt/Zn-γ-Al2 O3 and CoPt/Ni-γ-Al2 O3 possessed comparable catalytic performance,while CoPt/Al2 O3 exhibited the highest catalytic activity and the lowest CH4 selectivity,which confirmed that support texture and cobalt particle size seem to be major catalyst parameters affecting the catalytic performance of the final catalysts.