Co-Based Catalysts Supported on Silica and Carbon Materials: Effect of Support Property on Cobalt Species and Fischer–Tropsch Synthesis Performance

The influence of different support surfaces and physical structures on cobalt species and catalytic Fischer–Tropsch synthesis (FTS) performance has been investigated by using silica or mesoporous carbon as support. All the three catalysts Co/SBA-15, Co/SiO2, and Co/CMK-3 behaved differently in the FTS test and showed characteristic cobalt species. After calcination in argon, Co3O4 was prominent on both Co/SBA-15 and Co/SiO2 because of the stronger metal–support interaction. However, the weaker metal–support interaction on Co/CMK-3 coupled with the autoreduction of cobalt oxide facilitated the formation of more CoO on the support surface. On account of the higher reducibility and specific surface area, Co/SBA-15 exhibited higher CO conversion in FTS than another two as-synthesized catalysts. SBA-15 and CMK-3 possess well-ordered channel structure which favors mass transport and diffusion while diffusion inhibits hydrocarbon chain growth. The highest C5+ and C11–17 selectivities were observed over Co/SiO2 without regular channels, enabling enough intermediate residence time for carbon chain growth.