Enhanced activity and selectivity of Fischer-Tropsch synthesis catalysts in water/oil emulsions

Amphiphilic nanohybrid catalysts (Ru particles supported on carbon nanotube-metal oxide hybrids) enable the formation of water-in-oil emulsions and have a positive influence on the Fischer-Tropsch synthesis (FTS) activity and selectivity to desirable products in comparison with those obtained in single-phase solvents under the same reaction conditions. The reaction experiments were conducted at 473 K in a batch reactor that uses H ₂/CO syngas as a feed at 2.0-3.5 molar ratio and 4136.85 kPa total pressure. One of the main effects observed when using the biphasic mixture instead of a single solvent is the spontaneous separation of products by solubility differences, which affect mass-transfer-dependent secondary reactions. Another positive effect of using the biphasic system arises from the enhanced FTS activity observed in the presence of condensed aqueous phase. Finally, the presence of an emulsion seems to improve the C₁/C ₅₊ product balance, which can be explained by a dual-site model recently proposed in the literature.