(611h) Effect of Carbon Support on Supercritical Fluid Mediated Fischer-Tropsch Synthesis with an Iron-Based Nanoscale Catalys

Fischer-Tropsch synthesis (FTS) is a well-established catalytic process to produce hydrocarbon fuels and chemicals from syngas. Traditionally, FTS has been conducted in either the gas phase or slurry phase, but in each case, the heterogeneous nature of the process can lead to heat and mass transfer limitations. These limitations in turn can cause poor selectivity, shorten catalyst life, or necessitate a more complex reactor system. As an alternative, conducting the reaction in a supercritical fluid reaction medium allows for single phase, fixed-bed operation and has been shown to extend catalyst life, reduce CH₄ and CO₂ selectivity, and aid in the extraction of reaction intermediates as well as heavy products.

Because FTS is a surface-catalyzed reaction, it stands to benefit from the significant surface area per mass offered by nanoparticle catalysts. These nanoparticles, however, must be supported in order to reduce attrition, maintain dispersion, and provide mechanical strength. Traditional supports such as SiO₂ and Al₂O₃ can be used, but can have overly strong interactions with small particles, inhibiting reduction and reducing activity. Carbon-based supports such as nanotubes, nanofibers, and graphene offer a promising alternative, because they are stable and inert under FTS reaction conditions and do not adversely affect catalyst reduction. This paper presents the systematic characterization of multiple carbon-supported, iron-based catalysts coupled with a comparison of their FTS performance in both gas phase and supercritical phase operation.