379001 Controlling Metal Nanoparticles in Fischer Tropsch Synthesis
Controlling Metal Nanoparticles in Fischer Tropsch Synthesis
Jorge Gascon, Freek Kapteijn
The growing concerns about oil depletion have spurred worldwide interest in finding alternative feedstocks for important petrochemical commodities and fuels. Fischer-Tropsch synthesis (FTS) is a surface polymerization reaction where syngas (a mixture of CO and H2), derived from natural gas, coal, or biomass, is catalytically converted to hydrocarbons over Co, Ru, or Fe catalysts.1,2 This technology has long been considered as an alternative process to produce long chain paraffins via the so-called gas-to-liquids (GTL) process. Owing to their high activity and selectivity to long chain hydrocarbons, Co-based catalysts are the preferred choice. However, earth abundant and cheap Fe displays superior properties over Co-based catalysts, especially for syngas derived from coal (CTL) or biomass (BTL). As compared to Co, Fe is more resistant to poisoning by contaminants that may be present in the syngas feed such as sulfur and ammonia. In addition, Fe-based catalysts are active in the water-gas-shift reaction under typical FTS conditions, enabling the in-situ re-adjustment of the H2/CO molar ratio for the conversion of hydrogen lean syngas originating from coal or biomass.1 Furthermore, the product slate of Fe-based catalysts is more directed to short chain (unsaturated) hydrocarbons and short chain oxygenates, both among the most important chemical building blocks.
The main challenge in the design of stable FTS catalysts lies in overcoming the high deactivation rate due to sintering, carbon deposition and phase changes. During this lecture, we will highlight different synthesis strategies able to deliver very stable, active and selective FTS supported catalysts.
(1) Abelló, S.; Montané, D. ChemSusChem 2011, 4, 1538.
(2) Sun, B.; Xu, K.; Nguyen, L.; Qiao, M.; Tao, F. ChemCatChem 2012, 4, 1498.