Fischer-Tropsch Synthesis on Cobalt Catalysts: Structural Requirements and Reaction Pathways

摘要

Fischer-Tropsch synthesis turnover rates on supproted Co catalysts are independent of Co dispersion and of support identity over the accessible dispersion range (0.01-0.12). Turnover rates increase when small amounts of Ru (Ru/Co<0.008 at.) are added to Co catalysts. Co dispersions above 0.15 lead to rapid deactivation during reaction. Optimum dispersions (0.10-0.15) can be achieved, even at high Co loadings, by slow reduction of supported Co nitrate precursors. C_5~+ selectivity increases with increasing Co site density because diffusion-enhanced readsorption of alpha-olefins reverses beta-hydrogen abstraction chain termination steps.