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.