Effects of Co3C formation on the catalytic performance for Fischer-Tropsch synthesis over Co/SiO2 catalysts

•Co/SiO2 FTS catalysts with Co, Co3C, and Co2C phase are synthesized by controlling carburization time.•The phase structure of Co3C is revealed with XPS and HRTEM.•The Co/SiO2 catalyst with Co3C phase exhibits the highest activity among three catalysts.•CO pulse techniques reveal that Co3C with less active sites performs the highest intrinsic activity for CO activation, supporting its high activity towards FTS reaction.