Fischer-Tropsch synthesis: Towards a highly-selective catalyst by lanthanide promotion under relevant CO2 syngas mixtures

The role of lanthanides as promoters on cobalt-based catalysts for Fischer-Tropsch synthesis was evaluated under relevant biomass-derived syngas mixtures. Cerium, lanthanum and a combination of them were impregnated on an industrial cobalt-based micro-catalyst. Lanthanide incorporation did not affect significantly the morphology of the catalyst, although it reduced the available surface cobalt. Catalytic tests revealed that both the presence of carbon dioxide in the feed and lanthanides in the catalyst led to similar outcomes; higher selectivity to long-chain hydrocarbons, at the expense of reactivity. Reaction experiments were well aligned with in-situ DRIFTS measurements, which evidenced the modification of the initial reaction mechanism, CO 2 conversion and the presence of lower CO-cobalt coverages. This work reports two relevant findings for FTS development. Firstly, the presence of carbon dioxide is beneficial for long-chain hydrocarbon production. Secondly, the incorporation of lanthanides increases the production of gasoline, kerosene and diesel fractions. The presence of carbon dioxide in the gas mixture and lanthanides in the catalyst formulation modifies the reaction mechanism by improving the selectivity to liquid fractions • The presence of CO 2 incorporates rWGS into the reaction mechanism. • CO 2 shifts the product distribution to longer chain hydrocarbons. • Cobalt catalysts promoted by lanthanides are more selective to liquid fractions. • Combination of lanthanides and CO 2 decreases the cobalt active site availability. • The proposed system leads to higher selectivity but lower reactivity.