Co/Pillared Clay Bifunctional Catalyst for Controlling the Product Distribution of Fischer−Tropsch Synthesis

Pillared interlayer clays (PILCs) were synthesized by pillaring montmorillonite with SiO 2, Al 2 O 3, and ZrO 2, and Co-supported PILCs were prepared by the impregnation method. For comparison, Co/SiO 2 and Co-supported montmorillonite treated with dilute HNO 3 (acid-clay) were also prepared. The materials were characterized by XRD, H 2 -TPR, NH 3 -TPD, O 2 titration, and N 2 adsorption−desorption. The Co-supported catalysts were comparatively investigated for Fischer−Tropsch (FT) synthesis in a fixed-bed reactor under the conditions of 1 MPa, 508 K, H 2 /CO = 2, and W / F = 5.02 g·h·mol −1 . The results indicate that the activities of the catalysts (i.e., CO conversions) increase in the order of Co/Na-Clay ≪ Co/Si-PILC ≈ Co/acid-clay ≈ Co/Al-PILC < Co/Zr-PILC ≈ Co/SiO 2 . Moreover, Co/PILCs can effectively narrow the product distribution of FT synthesis showing significantly increased C 5 −C 12 selectivity and much decreased C 21+ selectivity. The results are well explained based on the acidic properties of the PILCs together with the textural properties, pore size distributions, and reduction behaviors of the catalysts.