Studies on KIT-6 Supported Cobalt Catalyst for Fischer–Tropsch Synthesis
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 compared to amorphous SiO2 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 SiO2 supported cobalt catalyst, KIT-6 supported cobalt catalyst displayed higher methane selectivity at a similar Co loading, likely due to diffusion effects.
KeywordsFischer–Tropsch synthesis KIT-6 Cobalt Mesoporous silica Catalyst
This research was carried out, in part, at the National Synchrotron Light Source, Brookhaven National Laboratory, which is supported by the U.S. DOE, Divisions of Materials Science and Chemical Sciences, as well as at the Nanotechnology Center at the University of Louisville. Special thanks to Drs. Syed Khalid and Nebojsa Marinkovic (Beamline X18b, NSLS, Brookhaven) for help with XAFS studies and Joel Young (University of Oklahoma, Dept. of Physics) for XAFS cell construction.
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