Transient Kinetic Investigation of Chain Growth during CO Hydrogenation on Co/TiO2 under Fischer-Tropsch Conditions: Elemental Balance of Species Adsorbed at the Catalyst Surface

CO hydrogenation is a promising approach for the storage of renewable energy in the form of hydrocarbons via the Fischer-Tropsch synthesis (FTS). Since transient operation of FTS reactors might be necessary and even be beneficial, transient kinetics for a rational catalyst and reactor design are essential. In order to advance the development of such transient kinetics, the periodic transient kinetics (PTK) method was applied to the CO hydrogenation on a Co/TiO2 catalyst under FT-like conditions. It was revealed that there are two carbon species of different reactivity, Cα and Cβ, present on the catalyst surface during the reaction. Cα forms fast within a few seconds and is highly reactive, while Cβ forms slowly, is accumulating on the surface over a longer time and imposes an inhibiting effect. However, a contribution of Cβ to the chain growth reaction was shown. Finally, the transient experimental results are evaluated based on a material balance and the amounts of Cα and Cβ present on the catalyst surface during the reaction were determined.