钍对浸渍型和蛋壳型钴基催化剂Co／SiO2费托合成性能的影响

Effect of Thorium on Fischer-Tropsch Synthesis Performance over Impregnated and Eggshell Co/SiO2

分别采用浸渍和喷涂方法制备了浸渍型钴基催化剂（i-Co／SiO2）和蛋壳型催化N（e-Co／SiO2），添加锕系元素钍（Th）作为催化剂助剂，利用X射线衍射（XRD）分析了催化剂晶相结构，H2程序升温还原（H2-TPR）表征了催化剂的还原性能，一氧化碳加氢反应评价了催化剂的费托合成反应性能．结果表明：添加钍对浸渍型和蛋壳型两种催化剂均可提高重烃（C5＋）的选择性，抑制甲烷和轻烃的生成．对于浸渍钴基催化剂，Th助剂可促进活性相的分散，从而提高催化剂活性．而对于蛋壳型钴基催化剂，Th助剂的添加可覆盖部分表面活性中心，从而降低催化剂活性．

Modification of impregnated Co/SiO2 （i-Co/SiO2） and eggshell Co/SiO2 （e-Co/SiO2） through addition of thorium （Th） was obtained by impregnation and spray coating processes, respectively. The effects of thorium on the structure, reduction behavior, and catalytic performance were characterized by X-ray diffraction （XRD）, H2 temperature-programmed reduction （H2-TPR）, and CO＋H2 reaction. We found that the addition of Th in both impregnation and eggshell catalysts could improve selectivity towards heavy hydrocarbons （C5＋） and suppress the formation of methane and light hydrocarbons. In impregnated Co/SiO2 catalysts, the presence of Th could promote dispersion of the active phase to enhance catalytic activity. However, when Th is added to eggshell Co/SiO2 catalysts, it may cover part of the active phase, leading to activity decline.