(172g) The Use of Nanoparticle Oxides as Supports for Cobalt-Based Fischer-Tropsch Catalysts

In our investigation a fixed bed reactor system was used to test our catalysts. Several catalysts were prepared using the incipient wetness impregnation method of cobalt precursors onto nanoparticle and porous silica, titania, and alumina supports. These catalysts were subjected to Fischer-Tropsch reaction conditions, in which CO and H2 are converted to hydrocarbons at a pressure of 20 bars and temperatures in the range of 210 to 250°C, to determine the differences in CO conversion and selectivity to liquid hydrocarbons between catalysts supported on nanoparticle and porous oxides. The use of promoters, both oxide and noble metal promoters, were also investigated to determine if the choice of optimal promoter is dependent on whether the nanoparticle oxides or porous supports are used. The catalysts were characterized using a number of analytical techniques, such as BET to determine the overall catalyst surface area, CO chemisorption to determine Co metal surface area, temperature programmed reduction (TPR) to determine the reduction properties of the catalyst, X-ray diffraction (XRD) to determine the crystal structure and size of the catalyst components. Initial results reveal that the porous silica (Alfa Aeasar) gives a higher conversion and a higher selectivity towards liquid hydrocarbons than the nanoparticle silica (NanoScale). In general, the titania-supported catalysts required higher temperatures in our experiments to show CO conversions comparable to the silica supported catalysts. Initial results indicate that nanoparticle titania (NanoActive) performs better than porous titania (Alfa Aesar). Work in progress involves using different promoters with the nanoparticle supports to increase the activity and selectivity to the diesel fraction.