(29f) Enhancement of the Activity and Selectivity of the Fischer-Tropsch Synthesis with Water/Oil Emulsions

Liquid phase reactions at the water/oil interface of Pickering emulsions have shown great advantages in heterogeneous catalysis. For example, solubility differences can drive the migration of desirable products to a different phase, thus facilitating the separation/removal of products and avoiding undesirable reactions. In recent work, we have used metal-doped nanohybrids (carbon nanotubes – metal oxide) to stabilize emulsions during Fischer-Tropsch synthesis catalysis. We observed that the emulsion system extends the life of the catalyst and improves the C₁/C₅₊ product balance. Also, Aliphatic hydrocarbons migrate preferentially to the oil phase while short alcohols remain in the water phase, which facilitates the separation of products. In this contribution, we systematically studied the effects of support hydrophobicity and emulsion properties on the activity and selectivity enhancements observed during Fischer-Tropsch synthesis. Carbon nanotubes with varying hydrophilicity are decorated with Ru metal and tested for liquid-phase Fischer-Tropsch synthesis using a batch reactor (H₂:CO = 4:1, 220 °C, 55 Bar). Different ratios of water/oil are also used and the emulsion properties characterized. Interestingly, emulsions stabilized with a more hydrophobic support (pristine carbon nanotubes) show CO consumption rates nearly twice those observed in single water phase. The results of catalytic activity and selectivity are discussed in terms of the relationship between emulsion properties and the interaction of the catalyst particles with the water and oil phases at the interface of the emulsion.