Hydrophobic promoter in physical proximity stabilizes cobalt catalysts for durable Fischer-Tropsch synthesis.

Cobalt catalysts have been widely studied for Fischer-Tropsch synthesis, yet they gradually deactivate under water-rich reaction conditions. Current stabilization strategies rely on complex catalyst compositions or even use noble-metal promoters. Here, we demonstrate that cobalt deactivation can be effectively hindered by physically regulating water diffusion. By physical mixing of a classical Co/SiO2 catalyst with hydrophobic polydivinylbenzene, a microenvironment is created that promotes directional water transport away from the cobalt. As a result, stable Fischer-Tropsch operation is achieved for 1200 hours, maintaining high activity with 88-90% selectivity toward C5+ hydrocarbons, minimal methane and CO2 production. Mechanistic investigations suggest that the combination of hydrophobic polymer could promote directional water removal from the catalyst surface. These findings demonstrate a practical strategy for stabilizing highly water-sensitive catalysts.