Chemical and structural effects of silica in iron-based Fischer-Tropsch synthesis catalysts

► Chemical and structural effects of silica on iron-based catalysts were investigated. ► Silica interacts with Fe to form FeOSi bond and disturbs the electron structures of Fe atoms. ► Silica largely decreases the iron particles and strengthens H, C, and O adsorptions on iron sites. ► High-silica-promotion largely suppresses the formation of methane.