Studies on KIT-6 Supported Cobalt Catalyst for Fischer–Tropsch Synthesis Muthu Kumaran Gnanamani • Gary Jacobs • Uschi M. Graham • Wenping Ma • Venkat Ramana Rao Pendyala • Mauro Ribeiro • Burtron H. Davis Received: 28 August 2009 / Accepted: 2 November 2009 / Published online: 14 November 2009 Ó Springer Science+Business Media, LLC 2009 Abstract KIT-6 molecular sieve was used as a support to prepare cobalt catalyst for Fischer–Tropsch synthesis (FTS) using an incipient wetness impregnation method to produce cobalt loadings of 15 and 25 wt%. The catalysts were characterized by BET surface area, X-ray diffraction, scanning transmission election microscopy (STEM), extended X-ray absorption fine spectroscopy and X-ray absorption near edge spectroscopy. The catalytic properties for FTS were evaluated using a 1L CSTR reactor. XRD, pore size distribution, and STEM analysis indicate that the KIT-6 mesostructure remains stable during and after cobalt impregnation and tends to form smaller cobalt particles, probably located inside the mesopores. The mesoporous KIT-6 exhibited a slightly higher cobalt dispersion com- pared to amorphous SiO 2 supported catalyst. With the higher Co loading (25 wt%) on KIT-6, partial structural collapse was observed after the FTS reaction. Compared to an amorphous SiO 2 supported cobalt catalyst, KIT-6 sup- ported cobalt catalyst displayed higher methane selectivity at a similar Co loading, likely due to diffusion effects. Keywords Fischer–Tropsch synthesis  KIT-6  Cobalt  Mesoporous silica  Catalyst 1 Introduction Fischer–Tropsch (FT) synthesis is a well known reaction for producing very clean alternative fuels from coal, natural gas, and biomass-derived syngas (CO and H 2 ). Cobalt-based catalysts are widely used in FT synthesis, especially when high molecular weight paraffins are pre- ferred [1]. Cobalt is usually supported on a high surface area support, such as SiO 2 or Al 2 O 3 , and to a lesser extent TiO 2 with both microporous and mesoporous structures in order to obtain a high metal dispersion [2–5]. In the FT synthesis, the catalytic behavior of silica-supported cobalt catalysts was found to depend on the nature of the cobalt species, the cobalt particle size, and the texture of supports [6–8]. Recently, highly ordered mesoporous silica, such as MCM-41, FSM-16, SBA-15, and HMS, have attracted much attention because of their well-defined periodic mesoporous large pore volume and their high surface areas that may reach 1,000 m 2 /g. This structure offers wide opportunities for tuning the particle size of deposited metals [9–11]. CoRu/MCM-41 catalysts were reported to be more active than a CoRu/SiO 2 catalyst for the FT syn- thesis process at similar metal loadings, and exhibited similar product selectivities [12]. On the other hand, Wang et al. [13] observed lower FT synthesis activity and higher methane selectivity for highly dispersed cobalt catalysts on SBA-15 using either cobalt acetate or cobalt acetylaceto- nate precursors during catalyst preparation. Recently, Martinez et al. [14] showed higher FT synthesis activity per weight of Co metal on SBA-15 than the Co/SiO 2 system with only minor differences in product selectivity. Thus, it is obvious that the metal-support interaction plays an important role in cobalt-based FT synthesis, and catalysts should be designed to achieve higher site densities as well as better product selectivity. In this study, the effect of cubic mesoporous silica, KIT-6, on the structure and FT synthesis activity of cobalt catalysts was studied and compared with a conventional amorphous silica supported catalyst. KIT-6 supported cobalt catalysts have shown a M. K. Gnanamani  G. Jacobs  U. M. Graham  W. Ma  V. R. R. Pendyala  M. Ribeiro  B. H. Davis (&) Center for Applied Energy Research, University of Kentucky, 2540 Research Park Dr, Lexington, KY 40511, USA e-mail: davis@caer.uky.edu 123 Catal Lett (2010) 134:37–44 DOI 10.1007/s10562-009-0213-7