CoAl2O4/Al2O3载体对钴基费托催化剂反应性能影响的研究

通过浸渍和高温焙烧,制得表面附着CoAl₂O₄微晶颗粒的改性Al₂O₃载体,并采用等体积浸渍法制备负载型Co基催化剂。结合 N₂物理吸附、XRD、H₂-TPR、XPS及H₂化学吸附等表征手段,研究改性载体及其负载钴基催化剂的织构特征;采用费托合成反应评价其催化性能。结果表明,Al₂O₃改性后,表面CoAl₂O₄的存在有效减少了载体与活性组分Co的相互作用,显著提高了催化剂的还原度和催化活性。载体的改性量在20%左右达到最佳值,继续增加,催化剂还原度和活性基本不再升高。载体改性促使催化剂CH₄选择性有所降低,C₅₊选择性略有提高。

Catalytic properties of CoAl2O4/Al2O3 supported cobalt catalysts for Fischer-Tropsch synthesis

The γ-Al₂O₃ modified with CoAl₂O₄ by the impregnation method was used as support to prepare cobalt catalysts. The physicochemical properties of the prepared catalysts were characterized with BET, XRD, H₂-TPR and XPS techniques and H₂-chemisorption experiment. The catalytic properties of the prepared catalysts were investigated for Fischer-Tropsch synthesis. It was shown that CoAl₂O₄ existed on the surface of γ-Al₂O₃, and thus, effectively weakening the interaction of Co and Al₂O₃ and resulting in a great increase in the reduction degree and the catalytic activity. The sample with a CoAl₂O₄ content of 20% shows the highest catalytic activity. It is worth noting that the CoAl₂O₄ modification decreased the CH₄ selectivity but enhanced the C₅₊ selectivity and catalytic stability.