Effect of support and cobalt precursors on the activity of Co/AlPO4 catalysts in Fischer–Tropsch synthesis

Cobalt supported on amorphous aluminum phosphate (Co/AlPO4) catalysts were prepared by the impregnation method using three different cobalt precursors such as cobalt nitrate, acetate and chloride to elucidate the activity of Fischer–Tropsch synthesis. The use of AlPO4 as a support for cobalt-based catalysts exhibits better catalytic performance during FTS reaction than the corresponding Co/Al2O3 catalyst. TPR results also suggest that the reducibility of the catalysts varies with the nature of cobalt precursors employed during the impregnation on AlPO4 support. The Co/AlPO4 catalyst prepared from cobalt nitrate shows higher CO conversion and C8+ selectivity than the others due to the facile formation of homogeneous cobalt particles with proper electronic characters and high reducibility. Interestingly, all Co/AlPO4 showed a growth of filamentous carbon initiated from the large mobile cobalt particles during the reaction. The differences in catalytic properties of Co/AlPO4 are mainly attributed to the cobalt particle size, reducibility with different electronic states of metallic cobalt, pore diameter of AlPO4 and formation of filamentous carbon.

Graphical abstractCobalt catalysts supported on amorphous aluminum phosphate (AlPO4) were prepared by using three different cobalt precursors to elucidate the activity of Fischer–Tropsch synthesis (FTS). The differences in catalytic properties of Co/AlPO4 are attributed to the cobalt particle size, reducibility and formation of filamentous carbon.Figure optionsDownload full-size imageDownload as PowerPoint slide