The preparation and study of sol–gel synthesized Co/Zn/TiO2 Fischer–Tropsch catalysts

The sol–gel method was used to prepare Co(10 wt%)/Zn(x)/TiO2 (x = 0, 1, 5 and 10 wt%) catalysts. Two methods were used to gel the catalyst precursors (Co, Zn, TiO2): (i) co-gelling all the components and (ii) gelling the titania support alone followed by the impregnation of zinc and cobalt precursors. The catalysts prepared by co-gelling all the catalysts components together were tested for Fischer–Tropsch (FT) activity and <5% conversion was obtained using standard FT conditions. This finding correlates with the strong interaction between the support and the Co, even in the presence of zinc. Impregnation of the sol–gel prepared titania support with zinc and cobalt precursors resulted in different degrees of interaction between the support and cobalt catalysts (due to the presence of zinc) as determined from TPR and XPS measurements. However, the modified sol–gel prepared catalysts also showed low activity towards Fischer–Tropsch (FT) when compared to the catalysts prepared using Degussa titania as support.

Graphical abstractThe sol–gel method was used to prepare Co(10 wt%)/Zn(x)/TiO2 (x = 0, 1, 5 and 10 wt%) materials that were tested as Fischer–Tropsch catalysts. While the influence of zinc was found to enhance FT activity, the poor reducibility of Co in these catalysts led to the generation of poor FT catalysts. Figure optionsDownload full-size imageDownload as PowerPoint slide