Influence of amines in the synthesis and properties of mesostructured aluminas and assessment as supports for Co-based Fischer-Tropsch synthesis catalysts

The influence of addition of amines (hexylamine, tripropylamine, dodecylamine, and hexadecylamine) and dopants (Zr, Ce) on the properties of mesostructured aluminas (MAs) synthesized using either Tergitol 15-S-9 or Triton X-114 surfactants was investigated. Selected MAs were evaluated as supports for Co and Ru-Co catalysts and their Fischer-Tropsch synthesis (FTS) performance assessed at 493 K, 2.0 MPa, and H-2/CO = 2. The materials were characterized by XRD, N-2 sorption, TG-DTG, EA, XPS, H-2-TPR, H-2 chemisorption, and STEM. Regardless of the surfactant, all amines enlarged the pore size of undoped MAs by ca. 2-3 nm. The impact of amines on BET area and pore volume depended, however, on the surfactant-amine combination and on the presence and concentration of dopants. The Ru-promoted catalyst supported on the MA synthesized with Tergitol-tripropylamine doped with Zr displayed the highest FTS activity and C5+ selectivity due to both high cobalt reducibility and optimum particle size (8 nm).