Promoter effect on the CO2-H2O formation during Fischer-Tropsch synthesis on iron-based catalysts

The effects of Mg, La and Ca promoters on primary and secondary CO2 and H2O formation pathways during Fischer-Tropsch synthesis on precipitated Fe/Cu/SiO2 catalysts are investigated. The chemisorbed oxygen atoms in the primary pathway formed in the CO dissociation steps reacted with co-adsorbed hydrogen or carbon monoxide to produce H2O and CO2, respectively. The secondary pathway was the water-gas shift reaction. The results indicated that the CO2 production led to an increase in both primary and secondary pathways, and H2O production decreased when surface basicity of the catalyst increased in the order Ca > Mg > La.