Modulating Fischer-Tropsch synthesis performance on the Co3O4@SixAly catalysts by tuning metal-support interaction and acidity

Abstract

ZIF-67 derived catalysts for Fischer-Tropsch synthesis have attracted much attention in recent years, while there is still a potential to improve their activity and selectivity. In this work, we prepared Si/Al co-immobilized Co 3 O 4 @Si x Al y catalysts by in-situ doping tetraethylorthosilicate and aluminum nitrate during the synthesis of ZIF-67. The effects of different Si/Al ratios on the metal-support interaction, acidity and FTS performance were explored. Results indicated that the Co 3 O 4 @Si 0 Al 4 catalyst exhibited the best FTS performance with the CO conversion as high as 79.9% and CTY (cobalt time yield) value of 19.5 × 10 −5 mol CO ·g Co −1 ·s −1 , which was ascribed to the moderate metal-support interaction and the most active Co sites. Meanwhile, the Co 3 O 4 @Si 3 Al 1 and Co 3 O 4 @Si 2 Al 2 catalysts exhibited higher iso-paraffin and olefin selectivity due to more acidic sites. The Co 3 O 4 @Si 0 Al 4 catalyst exhibited the highest FTS activity due to the moderate metal-support interaction (MSI), while the Co 3 O 4 @Si 3 Al 1 and Co 3 O 4 @Si 2 Al 2 catalysts showed certain hydrocracking and isomerization ability due to the formation of acidic sites. • Co 3 O 4 @Si x Al y catalysts were prepared by in-situ doping method based on ZIF-67. • The Co 3 O 4 @Si 0 Al 4 exhibited the highest Fischer-Tropsch synthesis (FTS) activity. • The high activity was due to moderate metal-support interaction and most active sites. • Acidic sites promoted the hydrocracking and isomerization of long chain hydrocarbons.