Effect of the CO coverage on the Fischer-Tropsch synthesis mechanism on cobalt catalysts

Abstract

Fischer-Tropsch (FT) synthesis, the conversion of CO and H2 to long-chain hydrocarbons, is performed at relatively low temperatures and high pressures. Density functional theory shows that the CO coverage on Co(0 0 0 1) increases gradually until a (√3 × √3)R30o-CO configuration (1/3 ML) is formed. This structure is stable over a relatively wide temperature and pressure range near FT conditions, until a phase transition to a (2√3 × 2√3)R30o-7CO structure occurs at high CO pressures. The 1/3 ML CO coverage reduces the H2 binding enthalpy from -121 to -74 kJ/mol and reduces the hydrogen coverage to